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601 Cards in this Set
- Front
- Back
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what is biology?
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this is the scientific study of living things
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definition of living things?
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these are all the organisms descended from a single-celled ancestor
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characteristics of living organisms
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1. consist of one or more cells
2. contain genetic information 3. use genetic information to reproduce themselves 4. are genetically related and have evolved 5. can convert molecules from their environment into new biological molecules 6. can extract energy from teh environment and use it to do bilogical work 7. can regulate their internal environment |
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living systems evolve through...
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these things evolve through differential survival and reproduction
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what is the central theme of biology?
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evolution - what to biology?
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who said and when?
"nothing in biology makes sense except in the light of evolution" |
Theodosius Dobzhansky
1973 - what did he write |
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what did Charles Darwin propose?
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that all living organisms are descended from common ancestors - evolution by natural selection
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what was charles darwin interested in?
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geology and natural science
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when and what did Darwin do on his voyage around the world
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he accepted a position on the HMS Beagle for a 5-year survey voyage- most important in galapagos islands
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what did darwin study in the glapagos islands
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he observed that species were similar to, but not the same as, species on the mainland of south america
he also realized that species varied from island to island |
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what did Darwin postulate from his studies on the galapagos island
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he postulated that species had reached the islands from the mainland, but then had undergone different changes on different islands
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what did Darwin propose as an explanatory theory for evolutionary change
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1. species change over time
2. divergent species share a common ancestor 3. the process that produces the change is natural selection |
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what helped darwin realize natural selection was possible
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humans select for desired traits when breeding animals (artificial selection) (foxhound vs beagle) then it is possible that nature to do the same selection process
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Columba livia
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300 varieties of dove derived form teh wild rock dove
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Darwin raised these as a hobby
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pigeons
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darwin postulated that natural selection could occur through...
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what occurs though differential selection and reproductive success
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define differential survival?
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not every organism will have the same chance for survival
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when years of research from darwin
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1831- 1858
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who wrote letter to darwin proposing an explanation of natural selection almost identical to darwin's
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alfed russel wallace
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who wrote a paper with darwin - when and who submitted
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July 1 1858
alfred russel wallace linnean society of london - work not understood - not received well |
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what book did darwin publish and when
- what did this book do? |
origin of species in 1859
- exhaustive evidence from many different fields to support evolution and natural selection - even incluced geological evidence |
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who were darwin adn wallus influenced by?
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economist Thomas Malthus - who had published An Essay on the Principle of Population
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what did Thomas Malthus publish and when
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An Essay on the Principle of Population
1838 - populations of all species have the potential for rapid increase - but this does not occur in nature, so death rate must also be high |
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if populations increase exponetially, supplies increast arithmatically, who dies if this is not seen in nature?
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very young and very old
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natural selection - define
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differential contribution of offspring to the next generation by various genetic types of belonging to the same population
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in evolutionary biology adaptation refers to :
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1. the process by which characteristics appear to be useful evolve
2. a phenotypic characteristic that makes it more likely the organism will survive |
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traits that increase the probability of survival and successful repordiction will increase in populations - give examples
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fall - leaves prevent moisture loss by losing leaves
carnicouous plants - adapted to living in poor soild areas - need amino acids not available in soil, so plant consumes flys |
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The basic structural and physiological unit of all living organisms is the
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cell is the basic...
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All living organisms acquire _______ from their environment.
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energy
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Which of the following represents a correct ordering of the levels of complexity at which life is studied, from most simple to most complex?
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Cell, tissue, organ, organism, population, community
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A prerequisite for the survival of life on land was the accumulation of
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O2 how was this important to suvival on land?
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A species is...
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a group of organisms that look alike and are capable of interbreeding. - what is this?
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Although Darwin’s voyage aboard the HMS Beagle took him around the world, most of his observations on natural history were made on the continent of _______ and its nearby islands.
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South America
Galapagos Islands - who studied here? |
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Darwin was influenced by _______ in his recognition that populations of animal and plant species have the potential to expand rapidly, but that in nature, this population growth is usually checked by high death rates.
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Thomas Malthus
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Domain Eukarya includes
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plants, amimals and fungi
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Heterotrophs obtain their energy from
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other organisms
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Name one thing that is not a feature of scientific hypotheses?
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They are unable to be falsified.
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define living thing
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all the diverse organism descended from a single-celled ancestor that evolved almost 4 billion years ago
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modern cell theory
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- all cells come from preexisting cells
- all cells are similar in chemical composition - most of the chemical reactions of life occur in aqueous solution within cells - complete sets of genetic information are replicated and pased on during cell division -viruses lack cellular stucture but remain dependent on cellular organisms |
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evolution
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change in the genetic makeup of biological populations through time
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adaptations
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structural, physiological or behavioral traits that enhance an organisms chances of survival and reporduction in its environment
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sexual selection
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selection due to mate choice
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genetic drift
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the random fluctuation of gene frequenceies in a population due to chance events
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cells genome
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the sum total of all the DNA molecules it contains
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DNA
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doxyribonucleic acid
long sequences of four different subunits called nucleotides |
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necleotides
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DNA base pairs
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Genes
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specific segments of DNA encoding the information the cell uses to make proteins
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proteins
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molecules govern the chemical reactions within the cells and form much of the organisms structure
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nutrients
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supply the organism with energy and raw materials for carrying out biochemical reactions
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snythesis
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building new complex molecules and atructures form smaller chemical units
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metabolism or metabolic rate
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the sum total of all the chemical transformations and other work done in all the cells of an organism
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differentiated
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specialized
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assemblages of differentiated cells are organized into...
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tissues
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different tissue types are organized to form ... that accomplish specific functions
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organs
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organs whose functions are interrelated can ge brouped into
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organ systems
(ex digestive system) |
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fuctions of cells, tissues, organs, and organ systems are all integral to the multicellular...
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organism
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a group of individuals of the same species that interact with one another is a
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population
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populations of all species that live and interact in teh same area are called a
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community
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communities together with their abiotic environment contstitute an
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ecosystem
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ecosystems exchange energy and create earth's...
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biosphere
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prokaryotes
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first unicellular organism consisting of DNA and other biochemicals enclosed in a membrane (bacteria)
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photosyntesis
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changed the nature of life on earth - build up of O2 and allowed life to move on land
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eukaryotes
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have nuclei and other internal components
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binomial
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biologists give each species a distinctive scientific name formed from two latinized names
first - genus second - species |
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genus
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a group of species that share a cecent common ancestor
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systematists
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scientists who study the evolution and classification fo lifes diverse organisms
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phylogentic trees
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document and diagram evolutionary relationships as part of an overarching tree of life
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name three major domains
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archaea
bacteria eukarya |
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domains of single celled prokaryotes
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archaea adn bacteria
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donmain of cells whose mitrochondria and chloroplasts may have originated from the ingestion of prokaryotic cells
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eukarya
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name three major groups of multicellular eukaryotes
- what group did they evolve from? |
plants, fungi, and animals
- each devolved from a different group of the eukaryotes generally referred to as protists |
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scientific method
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1. make observations
2. speculate, ask a question 3. form a hypothesis to answer the question 4. make a prediction: what else wold be true if your hypothesis is correct? 5. design and conduct an experiment that uses quantifiable data to test your prediction |
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hypothesis
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tentative answers to questions
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name two types of experiments
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controlled and comparitive
controlled - one variable changes comparitive - can't controll all variables - simply gathering and comparing data from different sample groups |
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null hypothesis
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assuming there is no difference
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what was charlse darwin passionately interested in?
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geology and natural science
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what happened in 1831 with Darwin?
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he was recommended for a position on teh HMS Beagle for a 5 year voyage around the world
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what did darwin observe with respect to parents and their offspring?
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he observed that, though offspring tended to resemble their parents, they are not identical
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what animal did darwin breed?
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pigeons
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what animal did darwin study on the galapagos island?
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finches - specifically their beaks
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artificial selection
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people breeding with specific characteristics in mind
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do individuals evolve?
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no - populations evolve
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who evolves?
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populations, not people
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population
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a group of individuals of the same species that live and interbreed in a particular geographic area
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adaptation
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the processes by which useful characteristics evolve; and the characteristics themselves
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those in a population who do not adapt to the environment...
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do not survive and do not pass on their genes
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gene
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segment of DNA that codes for a trait
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allele
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different form of a gene
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phenotype
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the physical expression of an organisms genes
ex brown eyes, the ability to digest gluten, predisposition to cancer |
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genotype
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the allele combination of a trait
Bb |
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homozygous
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both alleles are the same
BB or bb |
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heterozygous
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alleles are different
Bb |
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brassica oleracea
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through artificial selection 6 different plants can come from this single species depending on what trait is bred for:
1. cabbage - terminal buds 2. cauliflower - flower clusters 3. brussels sprouts - lateral buds 4. broccoli - stems and flowers 5. kohlabi - stem 6. kale - leaves |
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drosophila
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fruit fly
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mendelian populations
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locally interbreeding groups
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allele frequencies
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p = their proportion in the gene pool
estimated by counting alleles in a sample of individuals |
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how are allele frequencies estimated?
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by counting alleles in a sample of individuals
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equation for allele frequency
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p = # copies of the allele in population / sum of alleles in the population
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poymorphic
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more than one morph at that locus - ex Aa
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equation
frequency of allele A = |
2NAA + NAa / 2N
N= total number of individuals in the population |
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frequency of allele a =
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2Naa + NAa / 2N
N= total number of individuals in the population |
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If p is frequency of allele A
and q is freq of allele a then p+q = |
1
with hardy weinberg equilibrium taken into consideration |
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if there is only one allele at a locus, its frequency is
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1 and the population is monomorphic at that locus
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monomorphic
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one morph at that locus - AA only or aa only
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if certain conditions are met - teh genetic structure of a population...
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does not change over time
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hardy-weinberg equilibrium
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describes a model situation in which allele frequencies do not change
not ideal - to many variable in real life - mutations, unequal offspring |
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conditions that must be met to maintain hardy-weinberg equilibrium
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1. mating is random
2. populationsize is infinate. large populations aren't affected by genetic drift 3. no gene flow- no migration into or out of the population 4. no mutation 5. natural selection does not affect survival of any genotypes |
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if conditions hold, after one generation, genotype frequencies occur in these proportions
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AA p squared
Aa 2pq aa q spared |
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hardy-weinberg equilibrium is what type of hypothesis?
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null hypothesis - assumes evlolutionary forces are absent
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known evloutionary mechanisms that make hardy-weinberg non-realistic
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mutation
gene flow genetic drift nonrandom mating natural selection |
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genetic drift
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results form random changes in allele frequencies
allele frequencies drift away from the original frequencies effects small populations that colonie a new region -colonizing population is unlikely to have all the alleles present in the whole population |
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in large populations, genetic drift can influence frequencies of alleles that dont affect....
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survival and reproduction
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population bottleneck
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genetic drift can reduce the genetic drift - occurs in populations that are reduced to a snall number of individuals
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founders effect
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equivalent to a bottleneck
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natual selection
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adaptation occurs when some individuals in a population contribute more offspring to the next generation.
allele frequencies change in a way that adapts individuals to the environment that influenced that reproductive success. |
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natural selection acts on...
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phenotype
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fitness
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reproductive contribution of a phenotype (lifespan and #offspring) to subsequent generations
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changes to (what) of different phenotypes in a population leads to change in allele frequencies
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relative success
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natural selection can act on charaters with quantitative variation in three ways
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1. stabilizing selection
2. directional selection 3. disruptive selection |
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stabalizing selection
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preserves average phenotype
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directional selection
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favors individuals that vary in one direction
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disruptive selection
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favors individuals that vary in opposite directions from the average
- birds with average bills died out due to lack of access to food |
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sexual selection
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special type of natural selection, which acts on characters that determine reproductive success
if an individual survives but does not reproduce, it makes no contribution to the next generation favors traits that increase the chances of reproduction |
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intrasexual selection
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traits that may improve ability to compete for mates - ex bright colors, long horns
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intersexual seletion
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be more attractive to the opposite sex
reiably demonstrate the fitness of the bearer to the choosing sex |
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humans have also influenced the evolution of other species
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insecticiseds, antibiotics, hunting, moving species (plants, animals), changing climate
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species
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a "kind" of organism - group of actually or potentially interbreeding natual populations, which are reproductively isolated from other such groups
historically - fixed and unchanging creations of God - based on morphological characteristics |
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problems with concept of species
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1. all dogs come from canis lupus
2. red wolf - hybrid or species, do we protect it? 3. asexually reproducing species 4. ring species (salamanders) |
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geographic speciation
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populations are separated by a physical barrier
- once barrier is removed populations mingle but do not interbreed |
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allopatric speciation
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Allopatric speciation (from the ancient Greek allos, "other" + Greek patra, "fatherland") or geographic speciation is speciation that occurs when biological populations of the same species become isolated due to geographical changes such as mountain building or social changes such as emigration. The isolated populations then undergo genotypic and/or phenotypic divergence as: (a) they become subjected to different selective pressures, (b) they independently undergo genetic drift, and (c) different mutations arise in the populations' gene pools.
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sympatric speciation
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does not require physical isolation
disruptive selection required - ex birds with average beaks die off due to lack of access to food most commonly occurs by polyploidy |
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polyploidy
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duplicaiton of the whole set of chromosomes
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autopolyploidy
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chromosome duplication in a single species
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allopolyploidy
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combining of chromosomes from two species
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reproductive isolation
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1. prezygotic
a. habitat b. temporal c. behavioral d. mechanical e. gametic 2. postzygotic a. low hybrid viability b. hybrid infertility |
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prezygotic
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before fertilization barriers prevent fertilization
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habitat isolation
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individuals live in different habitats
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temporal isolation
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individuals breed at different times (frogs)
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behavioral isolation
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individuals fail to recognize each other as potential mating partners
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mechanical isolation
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individuals cannot copulate with each other because of anatomical differences in their genitalia
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gametic isolation
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sprem cannot fertilize eggs
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postzgotic barriers
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prevent the production of viable fertile offspring
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low hybrid viability
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hybrid offspring are less likely to survive, either as zygotes (dying during development) or as adults (dying before they can mate)
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hybrid infertility
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hybrids may survive, but they cannot produce offsprng (a mule is the sterile offspring of a horse and a donkey)
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Which of the following modes of selection leads to a reduction in variation but no change in the mean?
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Stabilizing selection
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The binomial system of nomenclature, by which we still classify species, was originated by
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Carolus Linnaeus
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The biological species concept is most closely associated with which scientist
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Ernst Mayr
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Geographical speciation is also known as
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allopatric speciation
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Sympatric speciation requires
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disruptive selection.
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Despite inhabiting overlapping ranges, the western spotted skunk and the eastern spotted skunk do not interbreed. One reason for this lack of interbreeding is that the western species breeds in early fall and the eastern species breeds in late winter to early spring. This is an example of _______ isolation.
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temporal
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when and who recommended darwin for 5 year trip on the HMS Beagle
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John Henslow
1831 |
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after his ship voyage what did Darwin propose
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1. species change over time
2. diverent species share a common ancestor 3. mecahnism for change is natural selection |
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who did similar research to Darwin and published an presented work together with Darwin
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Alfred Russel Wallace
1858 |
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who was Wallace and Darwin influenced by (an essay on the principle of population)?
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Thomas Malthus (1838 wrote essay)
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what was called when Gregor Mendal's publications were rediscovered and people studied the mechnistic aspects of evolution as well as the broad evolutionary patters evident in nature?
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population genetics
modern synthesis |
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heritable trait
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characteristic at least partly determined by the organisms genes
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population genetics three goals?
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1. explain the pattrens and organization of genetic variation
2. explain the origin oand maintenance of genetic variation 3. understand the mechanisms that cause changes in teh allele frequencies in populatinos |
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gene pool
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sum of all copies of all alleles at all loci found in a population
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what can demonstrate the existence of considerable genetic variation in populations?
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lab experiments
ex. fruit fly - high and low bristle count bred from selection of regular bristle fly generations |
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mendelian populations
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locally interbreeding groups
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frequency
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an allele's proportion in the gene pool at a particular locus
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AA, Aa, aa - what is it called in a population when more than one genotype found
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polymorphic
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AA or aa - what is it called in a population when only one genotype found
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monomorphic and allele is said to be fixed
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genetic structure
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frequencies on different alleles at each locus and the frequencies of different genotypes in a mendelian poluation describe that poluations what?
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who deduced the conditionss that must prevail if the genetic structure of a population is to remain the same over time?
and when? |
Godfrey Hardy Wilhelm Weinberg
Hardy-Weinberg equilibrium 1908 only applies to sexually reproducing organisms |
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hardy-wienberg equilibrium
after one generation of random mating - what are the genotype frequencies? |
AA - p squared
Aa - 2pq aa - q squared |
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if generation has more homozygous individuals and fewer heterozygous individuals that would be expected this condition is called?
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heterozygote deficiency
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why is hardy-weinberg equilibrium important if populations in nature never meet the conditions?
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1. equation is useful for predicting the approximate genotype frequencies of a population from its allele frequencies
2. model describes the conditions required for there to be no evloution in a population |
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how does calculating allele frequencies allow us to measure evolutionary change?
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allele frequencies measure the amount of genetic variation in a population and comparing this over time allows for chnges (or lack there of) can be considered over time (evolution)
|
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principle of natural selection?
two meanings of adaptation? |
differential survival and reproductive success
1. processes by which characteristics that appear to be useful to their bearers evolve (evolutionary mechanisms that produce them) and the characteristics themeselves 2. phenotype characteristic that has made it more likely for an organism to survive and reproduce |
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evolutionary mechanisms that make hardy-weinberg equilibrium unrealistic
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1. mutation
2. gene flow 3. genetic drift 4. nonrandom mating 5. selection |
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mutation
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any change in the nucleotide sequences of an organisms DNA
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explain study of genetic composition of founding populations
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washington and chili vs europe with fruit flys
europe - 80 different chromosomal inversions washington, chili - 20 different inversions only a small part of the total genetic variation found in europe reached americas |
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give example of directional selection
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horns of cattle - longer horned parents could defend their young better and so they were able to pass on genes
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give example of stabalizing selection
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baby birth weight
babies with higher and lower birth weights die at a higher rate than babies born at average weights |
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when and what book did darwin write about sexual selection
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1871
The sescent of Man, and selection in relation to sex these features (that would inhibit survival) either improved the ability of their berers to compete for access to mates (intrasexual - ex brighter color makes it easier for mate to see them) or made their bearers more attractive to memebers of the opposite sex (intersexual) |
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name two experiments that test sexual selection
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1. widowbirds - tail length
2. zebra finches - carotenoid levels, immune sytems |
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give example of poulation bottleneck
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greater prairie chickens - reduced to about 50 in 1990s
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what are the constriants of evolution
|
lack of genetic variation can prevent evolution of potentiall favorable traits
- if not in population, it can't be passed on humans have also influenced -hunting, environment, pesticides, antibiotics |
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who developed the biological species concept and when
|
Ernst Mayr in 1940
species are groups of actually or potentially interbreeding natual populations, which are reproductively isolated from other such groups |
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who developed the binomial nomenclature and what called (two parts)
|
Carolus Linnaeus (Genus species)
|
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problem with species concept
|
hybrids or species (ex red wolf), asexual species, ring species (slamanders),
|
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what is required in sympatic speciation and what is not required
|
disruptive selection required
physical isolation |
|
sympatic speciation most commonly occurs by
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polyploidy
|
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who developed the binomial system of biological nomenclature by which species are named today?
|
carlolus linnaeus
|
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morphological species concept
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construct that assumes a species consists of individuals that "look alike" and that individuals that don't look alike belong to different species
|
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cryptic species
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instances in which two or more morphologically indistinguishable species do not interbreed (salamanders)
|
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lineage species concept
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species as branches on the tree of life
|
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reproductive isolation
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a state in which two populations can no longer exchange genes (ex salamanders)
|
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who proposed the biological species concept and what is it?
|
Ernst Mayr
"species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups" |
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allopolyploidy
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from teh combining of the chromosomes of two different species
|
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reinforcement
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strengthening of prezygotic barriers
|
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layers of rock
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strata
|
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who first discovered strata and when?
|
Nicolaus Steno
17th century |
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How do scientists date ancient events?
|
by ratio of isotope C14 : C12
current during lifetime, C14 no longer uptakes after death can go back up to 50,000 years carbon dating |
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when were eras established
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before ages of rocks were known
|
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how do scientists date events? how is the history of life divided?
|
divided into geologic eras, which are subdivided into periods
|
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bounderies are bosed on
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changes in fossils
|
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when did level of oxygen start to increase
|
after first photo-synthetic eukaryotes - (after first eukayotes)
about 1.5 billion years ago |
|
organisms are classified according to
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the period they were discovered
|
|
who established the binomial nomeclature system and when
|
1707-1778
carolus linnaeus Genus species ex Homo sapiens |
|
hierarchical system of nomenclature devloped by Linnaeus
|
Domain
Kingdom Phylum Class Order Family Genus Species King Phyllup Came Over For Good Spaghetti |
|
Phylogentic tree
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shows evolutionary relationships among lineages
|
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describ in 5 steps how phylogenetic tree is created
|
1. a species, population, or gene at one point in time
2. becomes a leneage as we follow its decendants through time 3. a split occurs when the ancestral lineage divides into two decendant lineages 4. and each leneage continues to evolve independently as different traits arise (red dots) 5. the lineages continue to split and a phylogenetic tree emerges |
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phylogenetic tree
define root |
the common ancestor for the group on the left
|
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phylogenetic tree
define node |
the splits in branches - indicate a division of one lineage into two
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what do teh positions of the nodes on the time scale indicate
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indicate the times of the corresponding speciation events
|
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how can branches be changed and does this affect the tree?
|
branches can be rotated around any node without changing the meaning of the tree
|
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synapormorphies
|
shared derived traits define a branch of a phylogenetic tree
note - trait at node is where species diverge |
|
phylogenetic tree
define ingroup |
group of organisms of primary interest
|
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phylogenetic tree
define outgroup |
closely related species known to be outside the group of interest
|
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taxonomists use taxa for what?
|
use taxa for biological classification
|
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classification
tree - wgat is a complete branch on the tree called |
clade
|
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paraphyletic group
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group includes the common ancestor and some, but not all, of the ancestor's decendants (pink)
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polyphyletic group
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does not include the common ancestor of the group (yellow)
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|
monophyletic group
|
includes the common ancestor and all decendants of that ancestor (blue)
monophyletic group can be removed from tree with a single cut |
|
Domains - list
|
Archaea
Bacteria Eukarya |
|
name 4 approaches to classifying organisms
|
1. two-kingdome system - Linnaeus
a. Plantae b. Animalia 2. five-kingdom system - Whittaker a. Monera b. Protista c. Fungi d. Plantae e. Animalia 3. six-kingdom system - Woese a. Eu-bacteria b. Archae-bacteria c. Protista d. Fungi e. Plantae f. Animalia 4. three-domain system - Woese a. Bacteria b. Archaea c. Eukarya |
|
Archaea - describe
|
once celled organisms
live in extreme environments (bad water - death vally, hot springs, etc) |
|
Protists - describe
|
one celled eukaryotic
example - amoeba |
|
Fungi - describe
|
excrete enzymes and absorb food
example - mushrooms |
|
what organisms believed to be first
|
prokaryotes
|
|
origin of mitrochondria and chloroplasts by
|
endosymbiotic - taking in without destroying - the two organisms then work together
|
|
endosymbiotic
|
taking in without destroying - the two organisms then work together
|
|
which is beleived to occur first - endosymbiotic origin of mitrochondria or endosymbiotic origin of chloroplasts?
when did this happen on domain tree? |
endosymbiotic origin of mitrochondria
happened after split from archaea |
|
members of all domains can?
|
1. conduct glycolosis
2. replicate DNA conservatively 3. have DNA that encodes peptides 4. produce peptides by transcription and translation using the same genetic code 5. have plasma membranes and ribosomes |
|
example of archaea
|
halophiles
methanogens |
|
halophile
|
example of archaea
"salt lover" - live in high salt and up to ph 11.5 |
|
methanogens
|
example of archaea
produce methane |
|
thermoplasma
|
example of archaea
no cell wall, themophilic and acidophilic - lives in coal deposits |
|
sulfobus
|
example of archaea
live in hot sulfur springs 70-75*C, pH 2-3 |
|
acidophilic hyperthermophiles
|
example of archaea
maintains interal temp of 7.0 |
|
name three bacteria shapes
|
helical
bacilli (rod) cocci (spherical) |
|
to group bacteria
|
shape
gram staining (yes.no) nutrition (parasites, photoautotrophs) metabolism High GC, low GC |
|
what kind of bacteria changed the earths atmosphere
|
cynobacteria
"pond scum" forms colonies that have three cell types - spores, vegetative cells and heterocysts |
|
what was the environement doing when eukaryotic cells were developed?
|
changing from anaerobic to aerobic
|
|
major events that occorred in evolution of eukaryotic cells are still...
|
conjectural (based on guesswork)
|
|
endosymbiosis - who developed theory
|
Lynn Margulis
|
|
eukaryotes that are neither plants, animals, or fungi are...
|
protists - what are these?
also called mirobial eukaryotes (though not all are microbial) |
|
how can protists or microbial eukaryotes be classified?
|
1. by locomotion
2. motil - cilia or flagella 3. amoeboid motion - pseudopods 4. immotile- stationary 5. reproduction - most are asexual, but some are sexual |
|
characteristics of heterotrophic fungi
|
1. absorptive heterotrophy (nutrition)
2. saprobes 3. parasites 4. mutualists 6 major groups |
|
absorptive heterotrophy (nutrition)
|
secrete digestive enzymes and absorb nutrients
|
|
saprobes
|
absorb sutrients from dead organic matter
|
|
parasites
|
abosrb nutrients from living hosts
|
|
mutualists
|
livein intimate association with another organism that benefits both. Mutually beneficial
|
|
name 6 groups of fungi
|
1. microsporidia
2. chytrids 3. zygomycota 4. glomeromycota 5. ascomycota 6. basidiomycota |
|
dashed line on phylogenetic tree means?
|
it indicates the probable paraphyly of the group
|
|
budding
ex. yeast |
mitosis followed by asymmetrical cell division
|
|
fungi reproduce rapidly when?
|
nutrient supplies dwindle
ex - after it rains |
|
predatory fungi do what?
|
they trap microscopic organisms
|
|
lichen
|
fungus and photosynthentic mircroorganism
mutalism 30,000 species |
|
what are the major groups of eukaryotes
|
kingdoms:
1. Plantae 2. Animalia 3. fungi 4. Protista |
|
all chloroplasts have what in common
|
all trace back to a single incidence of endosymobiosis
|
|
plantae phylogenetic tree has how many clades?
|
several
|
|
which is the closest living relative of the land plant?
|
charophytes
ex. coleochaeta alge stonewarts (genus Chara) sister group to plants |
|
classification of land plants
|
nonvascular land plants
ex. moss - not tall, very green, found in moist environments vascular plants (includes seed plants) |
|
*****************************
what are key characteristics that evolved and allowed plants to live on land ****************************** |
1. waxy cuticle
2. Gametangia 3. protected embryos 4. absence of herbivores (initially) 5. vascular tissue |
|
waxy cuticle
|
prevents dehydration
|
|
gametangia
|
cases to enclose gametes
|
|
vascular tissue
|
xylem - conducts water and minerals from soil upwards
phloem - conducts photosythetic products to roots for storage allows plants to grow taller and large root systems support their height |
|
nonvascular plants
|
do not have xylem and phloem - do not grow tall
need to live near water to reproduce lack typical leaves, roots, and stems |
|
what is considered oldest evolutionary plant
|
liverwort
|
|
root - common ancestor of seed plants - what are the nodes?
|
|
what is the outgroup and what is the ingroup?
|
gymnosperms (naked seeds) are the ingroup
angiosperms (flowering plants) is the outgroup |
|
what makes an animal and animal?
|
eukaryotic
multicellular heterotrophic metabolism movement (exception coral) |
|
if single cellular and eukaryotic
|
protist
|
|
to classify all animals we have to be...
|
general
1. body plan is the general structure 2. symmetry of body 3. body cavity structure (# layers) 4. segmentation of body 5. external appendages that move body |
|
animal feeding strategies
|
1. filter feeders
2. herbivores 3. predators 4. parasites 5. detritivore (eats dead organic material) |
|
sessile
|
stationary
|
|
motile
|
moving
|
|
what is a deuterosome?
|
characterized by three early developmental patterns:
1. radial cleavage 2. mouth forms opposite the blastopore 3. coelom develops from mesodermal pockets that bud off from the cavity of the gastrula |
|
evidence from DNA sequencing supports the monophyly of the deuterostomes:
|
1. echinoderms
2. hemichordates 3. chordates there are fewer species of deuterostomes than protostomes |
|
living fossil
|
coelacanth
|
|
coelacanth - why still here?
|
no natural predeters
able to reproduce isolated have multiple food source not commerical game fish |
|
difference between amphibians and reptiles
|
1. amphibians existed before reptiles
2. amphibian reproduction tied to water (vernal pools) 3. can live on land (amphibians must stay moist) 4. external fertilization (amphibians) and internal fertilization (reptiles) |
|
ex of amphibians and reptiles
|
Reptiles include alligators, crocodiles, turtles, and snakes. Amphibians include salamanders, toads, and frogs.
|
|
reptiles evolved before or after amphibians?
|
after
|
|
what adaptations did reptiles go through to survive on the land from water?
|
1. better lungs
2. hard shelled eggs 3. internal fertilization 4. scaly skin 5. kidneys excreted concentrated urine to prevent water loss |
|
human evolution
|
primates
opposable digits binocular vision bipedal (two legs) |
|
prehesile tail
|
tail can grasp
|
|
neutral allele
|
allele that does not affect the fitness of an organism
|
|
phylogeny
|
evolutionary history of relationships
|
|
node
|
a point at which lineages diverged in the past
|
|
taxon (taxa)
|
group of species that we designate or name
|
|
clade
|
any taxon that consists of all the evolutionary descendants of a common ancestor
|
|
systematics
|
the study and classification of biodiversity
|
|
homologous
|
any features shared by two or more species that have been inherited from a common ancestor
|
|
ancestral trait
|
a trait that was already present in teh ancestor of a group
|
|
derived trait
|
a trait found in a descendent that differs from its ancestral form
|
|
synapomorphies
|
derived traits that are shared among a group of organisms (viewed as evidence of the common ancestry of the group)
|
|
convergent evolution
|
independently evolved traits subjected to similar selection pressures may become superficially similar
(bones in bats and birds homologous, but wings are not - evolved independently) |
|
evolutionary reversal
|
a character may revert from a derived state back to an ancestral state
|
|
homoplasies
|
similar traits generated by convergent evolution and evolutionary reversals
|
|
morphological species concept
|
a construct that assumes a species consists of individuals that look alike
|
|
lineage species concept
|
species as branches on the tree of life - each species has a history that starts at a speciation event (one lineage on teh tre splits into two) and ends either at extinction or another speciation event, at which time the species produces two daughter species
|
|
reproductive isolation
|
a state in which two polulations can not longer exchange genes
|
|
polyploidy
|
the duplication of sets of chromosomes within individuals
|
|
allopolyploidy
|
the combining of the chromosomes of two different species
|
|
autopolyploidy
|
chromosome duplication in a single species
|
|
sedimentary rocks
|
rocks formed by the accummulation of grains on teh bottom of bodies of water
|
|
strata
|
the oldest layers fo rock
|
|
precambrian era
|
more than 3 billion years
life consisted of microscopic prodaryotes; eukaryotes eveolved about 2/3 of the way through the era |
|
all the plants living at a particular time or place
|
flora
|
|
all the animals living at a particular place or time
|
fauna
|
|
cambrian explosion
|
a geologically rapid diversification of life - took millions of years - oxygen concentration was approaching current level
|
|
name three eras
|
plaeozoic, mesozoic, cenozoic
|
|
synapormorhies
|
shared derived traits define a branch of a phylogenetic tree
|
|
taxonomists
|
use taxa for biological clasification
|
|
classifying organization - 4 version
|
1. LInneaus 2 kingdom
2. Whittaker - 5 kingdom 3. Woese - 6 kingdom 4. Woese - 3 domain |
|
all domains
|
going
round past every primate makes ripples conducts glycolosis replicate DNA produce proteins by translation and transpcription encodes proteins by using DNA plasmind membranes and ribosomes |
|
bacteria - how classified
|
shape
gramp pos/neg nutrition metabolism |
|
archaea - how classified
|
unique environments
sulfobus methangens |
|
eukaryotes - what kingdoms
|
protists
animilia fungi plantae |
|
protists - how classified
|
locomotion
- flagellum, cillia - amoeboid - immotile reproduction - asexual or sexual |
|
biofilms
|
microbials (prokaryotes) put down a gel like sticky polysaccaride matirx that makes it hard to remove organism
|
|
what makes an animal and animal
|
every
mouse has its momement eukaryote mulitcellular heterotroph internal digestion movement (ex coral -sperm) |
|
fungi - how classifed (heterothrpic)
|
1. absorptive heterotrophy
2. saprobes 3. parasites 4. mutualists |
|
abosroptive heterotrophy
|
secrete digestive enzymes and absorb nutrients
|
|
saprobes
|
abosorb nutrients from dead organic matter
|
|
parasites
|
absorb nutrients from living hosts
|
|
protosomes
|
mouth first
- blastophore becomes mouth |
|
deuterostomes
|
rear first
- blastophore becomes anus |
|
detritivore
|
eats dead or organic matter
|
|
sessile
|
stationary
|
|
prokaryotes have distintive cell walls
|
peptidoglycan - gram pos/neg
|
|
photoautotrophs
photoheterotrophs |
photoautotrophs - make own food (only need sunlight)
photoheterotroph - make own food, but require some compounds made from other organisms |
|
protists
|
eukaryotes that are not plant, animal, fungi
|
|
sporophyte
|
spore plant
|
|
gametophyte
|
gamete plant
|
|
heteromorphic
|
alternation of generations, where generations alternate morphology
|
|
isomorphic
|
generations do not alternate
|
|
diatom
|
symetrical protist
|
|
plantae - name 5 major clades
|
1. glaucophytes
2. red algae 3. chlorophytes 4. land plants 5. charophytes |
|
gametangia
|
gametes form wihtin specialized sex organs
|
|
what are unicellular fingi know as
|
yeasts
|
|
radial cleavage
|
fertilized egg dividing in an even pattern
|
|
what makes a mamal?
|
1. sweat glands
2. mamary glands 3. hair 4. four chambered heart |
|
angiosperms - what are they
|
flowering plants - vasular plants with seeds enclosed in modified leaves called carpels (seeds enclosed during pollination)
more recent evolution |
|
two clades of angiosperms
|
97% fall into these:
monocots eudicots |
|
monocots
|
narrow-leaved; grasses, lilies, orchids, palms
|
|
eudicots
|
broad-leaved; soybeans, roses, sunflowers, maples
|
|
what does remaining 3% of angiosperms look like?
|
structure similar to eudicots:
ex - water lilies, magnoliids |
|
cotyledons
|
A leaf of the embryo of a seed plant, which upon germination either remains in the seed or emerges, enlarges, and becomes green
|
|
how many cotyledons does eudocots/monocots have?
|
monocots - one
eudocots - two |
|
characteristics of monocots
|
1. one cotyledons
2. parallel veins in leaves 3. flowers usually in multiples of three 4. primary vascular bundles in stem are scattered |
|
characteristics of eudicots
|
1. two cotyledons
2. veins in leaves are usually netlike 3. flower parts usually arranged in fours or fives 4. arrangement of primary vasular bundles in stem are in a ring |
|
carpels
|
modified leaves of angiosperms
|
|
ame three types of vegetative organs of the angiosperms
|
1. roots
2. stems 3. leaves |
|
angiosperms organized into two systems
|
1. shoot systems
2. root systems |
|
shoot system
|
consists of stems and leaves in which photosythesis takes place
|
|
root systems
|
anchors and provides nutrients for the shoot system
|
|
morphology
|
structure of vegetative organs
and arrangement of component cells and tissues, or anatomy |
|
name three root systems
|
1. taproots
2. fibrous root system 3. prop roots |
|
taproots
|
single, large, deep-growing root, small side roots. The root may also function as food storage.
ex - sweet potato, carrot, beet |
|
fibrous system
|
many thin roots of equal diameter. Have large surface area; cling to soil well
ex - green onion |
|
prop roots
|
help support shoot
ex - corn |
|
potato tuber
|
underground stem
|
|
runners
|
horizontal stems
|
|
name an adaptation of a plant that lives in the desert
|
desert plants have enlarged stems that store water
|
|
vascular plants - name tissue systems
|
1. vascular
2. dermal 3. ground these systems extend throughout the plant body in a concentric arrangement |
|
dermal tissue system
|
outer covering of the plant
|
|
vascular tissue system
|
conducts water and solutes thoughout the plant
the transport system two parts, xylem and phloem |
|
ground tissue system
|
carries out photosynthesis, stores photosynthetic products and helps support the plant
|
|
xylem
|
part of the vascular system
distributes water and minerals taken up by the roots to all parts of the plant. xylem can also function in storage and support |
|
phloem
|
part of vascular system
transports carbohydrates from site of production (sources) to sites of utilization or storage (sinks) |
|
how are plant cells unique?
|
1. chloroplasts
2. vacuoles 3. have cell walls with cellulose (differ in composition depending on function of cell) |
|
describe cell walls in a plant
|
1. cell wall is outside the plasma membrane
2. cell walls can contain proteins and enzymes. chemical reactions can be important in cell expansion adn defense 3. except where waterproofed, cell walls are permeable to water and mineral ions |
|
cell wall formation in plants
|
1. final step in mitosis
2. end of cytokenesis, two daughter cells separate by cell plate 3. each cell secrestes three polysaccharides - cellulose, hemicellulose, and pectin 4. cells expand and primary cell walls thin 5. expansion stops and second wall may be deposited |
|
plasmodesmata
|
conect adjacent plant cells
cytoplasm-filled canals, traversed by a strand of ER sometimes expand to allow macromolecules, including transcription factors and RNA, and viruses, to pass. Doesn't require crossing a plasma membrane allow direct communication between plant cells |
|
what connects adjacent plant cells
|
plasomodesmata
|
|
plant cell types - name three
|
1. parenchyma cells
2. collenchyma cells 3. sclerenchyma cells 3a. fibers 3b. sclerids 4. xylem cells 4a. tracheids 4b. vessel elements 5. phloem cells 5a. sieve tube elements |
|
parenchyma cells
|
numerous in young plants
have thin walls, large central vacuoles photosynthetic cells in leaves are parenchyma cells with many chloroplasts many store starch and lipids starch is often stored in leucoplasts |
|
leucoplasts
|
starch is often stored in these
|
|
collenchyma cells
|
have thick primary cell walls, usually elongate shape
provides support to leaf petioles, non-woody stems, and growing organs tissue with collenchyma cells is flexible ex strings of celery |
|
sclerenchyma cells
|
thickened secondary walls
many die after secondary wall is laid down provide STRONG support |
|
sclerenchyma cells - name two types
|
1. fibers
2. sclerids |
|
sclerenchyma cells - fibers
|
provides rigid support
ex - bark of tree |
|
sclerenchyma cells - sclerids
|
packed together in a nuts shell or isolated clumps like the stones in cells of pears
|
|
xylem contains what types of elements, name element types and what do they do?
|
tracheary elements
1. tracheids 2. vessel elements usually die before assuming their function |
|
gymnosperm
|
meaning "naked seeds", after the unenclosed condition of their seeds (called ovules in their unfertilized state).
|
|
tracheids
|
gymnosperm have tracheid with pits in the secondary walls that allow materials to move freely
|
|
vessel elements
|
found in angiosperms
larger diameter than tracheid end walls break down after death forming hollow tubes |
|
seive tube elements
|
phloem transport cells
these are LIVING cells meet end to end adn transport carbohydrates |
|
meristem
|
undifferentiated plant tissue actively dividing (by mitosis)
|
|
early embriotic development - what two patterns contribute to basic body plan?
|
1. arrangement of cells and tissues along the main axis from root to shoot
2. concentric arrangement of tissue systems |
|
modules (plant)
|
growing stem consists of these laid down one after another
each module is a node with attached leaves, the internode below, plus axillary buds at the base of that internode think of a branch as a single module |
|
how do branches differ from animal limbs
|
they form one after another, they differ in number of leaves, and number of subsequent branches
|
|
branches vs leaves - which is long lived, which is short?
|
branches - long-lived
leaves - short-lived (weeks to years) |
|
root systems branching - describe
|
lateral roots may be semi-independent. as roots systems groww, roots may die and be replaced by new ones
|
|
all plants have a ____plat body
|
primary
|
|
which plants consist of primary plant body?
|
monocots
|
|
what has a secondary plant body and what does it consist of
|
trees and shrubs - consisting of wood and bark
|
|
secondary plant body
|
tissues are laid down as stems and roots thicken - grows throughout life
|
|
lateral meristems
|
cork cambium, vascular cambium
|
|
terminal bud
|
contains a shoot apical meristem
|
|
vascular cambium and cork cambium do what in what type of plants
|
thicken stem and root in woody plants
|
|
apical meristems
|
at tips of roots and stems, and in buds, give rise to the primary plant body
|
|
Shoot apical meristems
|
extend stems and branches
|
|
root apical ameristems
|
extends roots
|
|
name two types of apical meristems
|
1. Shoot apical meristems
2. root apical ameristems |
|
what do apical meristems give rise to?
|
to a set of cylindrical primary meristems that produce three tissue systems
|
|
name three tissue types of primary meristems
|
protoderm
ground meristem procambium |
|
what does protoderm tissue turn into
|
dermal tissue system
|
|
what does ground meristem tissue turn into
|
ground tissue system
|
|
what does procambium tissue turn into
|
vascular tissue system
|
|
root cap
|
daughter cells become part of root cap - constantly erodes away
|
label
|
|
|
lateral meristems
|
produce secondary growth
|
|
vascular cambium
|
supplies cells of secondary xylem (toward the inside) which becomes wood; and secondary phloem (towards the outside) which becomes bark
|
|
cork cambium
|
produces waxy-walled cork cells - some of the cells become the bark
|
|
how do meristems build the plant body?
|
lateral meristems, vascular cambium, cork cambium
|
|
wood
|
secondary xylem
|
|
bark
|
everything external to the vascular cambium (periderm plus secondary phloem)
|
|
what represents primary and secondary growth?
|
a twig - has both - apical meristems are enclosed in bud
- only the buds are entirely primary tissues |
|
buds of a plant are entirely what type of tissue?
|
primary tissue
|
label diagram
|
|
|
as tree grows - what happens to outermost layers?
|
outermost layers, including epidermis, dry and crack off
|
|
periderm
|
protective cells produced by cork cambium -
walls impregnated with suberin (waterproofing product) |
|
meristems remain active for how long? - example of oldest plant
|
years or centeries
bristlecone pine - Pinus longaeva 4900 years old |
|
root tissues:
protoderm ground meristem procambium ...give rise to |
1. epidermis
2. cortex and endodermis 3. stele (vascular cylinder) |
label
|
|
|
what does stele constist of
|
pericycle
xylem phloem |
|
pericycle
|
undifferentiated cells
1. give rise to lateral roots 2. gives riste to lateral meristems that thicken the root 3. cells have transport proteins that move nutrient ions into the xylem |
label root tissues
|
|
label - what is this
|
eudicot stele
|
label - what is this?
|
monocot stele
|
label - what is this
|
monocot vascular bundles in stem
|
label - what is this?
|
eudicot stem vascular bundles
|
|
stems may have storage tissue in center called..
|
pith
|
|
cortex may also function as what - and what my they contain
|
they may function as storage and contain collenchyma cells
|
|
what constitutes the ground system
|
pith and cortex
|
|
secondary groth results from what?
|
from the lateral meristems in eudicots
|
|
what is vasuclar cambium initially?
|
initially a single layer of cells between primary xylem and phloem
|
|
how do secondary phloem and secondary xylem form and where?
|
when vascular cambium divide they form secondary phloem (toward outside) and secondary xylem (toward inside)
|
|
describe what (plant example) and why monocots do have thickened stems
|
ex - palms
- don't have vascular or cork cambiums - wide apical meristem produces wide stem, and dead leaf bases also contribute to the stem |
|
how can you tell age of a tree in temerate region?
|
annual rings result from seasonal conditions
1. spring - water is plentiful - tracheids or vessel elements produced have large diameter 2. summer - less water - smaller diamter cells with thicker walls are produced |
label
|
|
|
name experiment that describes how leaves relate to annual rings
|
ponderosa pine - needles connect with the xylem formed in teh year in which the needles were formed
|
|
why does center of tree look darker - what called
|
as tree grows in diameter, the xylem in the center becomes clogged with water insoluble substances -
heartwood |
|
heartwood
|
center of tree - gets darker as tree gets older due to water insoluble substances
|
|
sapwood
|
xylem that actively conducts water
|
|
xylem that actively conducts water
|
sapwood
|
|
what are knots?
|
cross sections of branches
|
|
what are cross sections of branches
|
knots
|
|
how does leaf anatomy support photosynthesis
|
leaf anatomy is adapeted to carry out:
1. photosynthesis 2. exchange of O2 and CO2 with the environment 3. while limiting water losses |
|
name two zones of cells to make up mesophyll - what type of cells
|
parenchyma - cell type
1. palisade mesophyll 2. spongy mesophyll also include air for diffusion of gases |
label - what is this
|
eudicot leaf cross section
|
|
vascular tissues form ___ in leaves
- where are they in plants |
veins
- come within a few cell diamters of all the cells |
|
how are mesophyl cells well supplied with water and mineral
- and why needed? |
veins come within a few cell diamters of all the cells
products of photosyntheis can be conducted to the phloem |
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epidermal cells - describe function
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nonphotosynthetic
- have waxy cuticle that is impermeable to water - prevents water loss and diffusion of gas |
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what allows for gas exchange in a leaf
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stomata
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what are stomata controlled by
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guard cells
|
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if there is more solute on one side of the membrane - what does this mean in terms of water
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less water if more solute and water will move in.
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solute or osmotic potential
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teh greater the solute concentration, the more negatie the solute potential
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what is the driving force for osmosis to occur?
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differeing concentrations of water
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isotonic
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water concentration same
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hypertonic
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high concentration of water
in cell - water moves out |
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hypotonic
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conc of water is low in cell - water moves in
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tugor pressure
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water enters a cell due to its negative solute potential
entry of more water is resisted by an opposing tugor pressue |
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what happens if positive pressure potential is lost in a plant?
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plant wilts
|
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why would a plant wilt?
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because it lost its positive pressure potential
|
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pressure potential
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over long dinstances in xylem and phloem, the flow of water and dissolved solutes is driven by this
|
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wilted plant
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neg water potential
= neg solute potential no pressue potential |
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well watered healthy plant
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water potential =0
= neg solute potential equal pos pressure potential |
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bulk flow
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movement of a solution due to difference in pressure potential
|
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bulk flow in xylem is...
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between regions of different negative pressure potential (tension)
|
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bulk flow in phloem is...
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between regions of different positive pressure potential (turgidity)
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aquaporins
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membrane channel proteins that water can pass through rapidly
|
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abundance in plasma membrane and tonoplast depends on what
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a cell's need to obtain or retain water
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tonoplast
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vacuole membrane
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rate of water
direction of water - which can be controlled |
rate of water
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how do mineral ions pass membranes?
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transport proteins
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concentration gradient
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when molecules and ions move across membrane (from higher conc to lower) as permitted by membrane characteristics
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active transport
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conc of most ions in the soil solution is lower than that in the plant; uptate must be by this type of transport requiring energy
|
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symport protein
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together - protein in membrane that allows two molecules to pass through (ex H+ an Cl-)
|
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how do water and minerals move into stele? name two methods
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1. apoplast
2. symplast |
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apoplast
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cell walls and intercellular spaces form a continuous meshwork that water can move through without crossing any membranes
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symplast
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water passes through cells via the plasmodesmata
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label
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|
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what method must water use to enter stele
|
symplast
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describe how leaves pull xylem sap upward
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1. transpiration (water diffuses though stomata)
2.. water evaporates from mesophyll cells 3. tension pulls water from veins into mesophyll cells 4. tension ulls water upward into xylem of veins 5. tension pulls water up in xylem of the root and stem 6. water molecules form a cohesive water colum fromt eh roots to the leavs 7. water moves into the system by osmosis 8. water enters the root from soil by osmosis |
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guard cells - how do the open and close
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in the presence of light, K+ and CL- are transported in, water follows due to neg water potential in the guard cell and opening cell
at night, K+ isn't transported, water potenial increases and water stops moving in - makes guard cell go limp and close |
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how are substances translocated in the phloem?
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two steps in transloation require energy
1. transport of solutes from sources into sieve tubes (loading) 2. rmoval of solutes at sinks (unloading) combination is pressure flow model |
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pressue flow model
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combination of
1. transport of solutes from sources into sieve tubes (loading) 2. removal of solutes at sinks (unloading) |
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describe in 6 steps - the pressue flow model
|
1. transpiration pulls water to xylem vessels
2. source cells load sucrose into phloem sive tubes, reducing their water potential 3. so water is taken up from xylem vellels by osmosis - raising teh pressure potential in the sieve tubes 4. interal pressure differences dreive the sap down the sieve tube to sink cells 5. sucrose is unloaded into sink cells... 6. and water moves back to xylem vessels |
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where are sex organs in angiosperms
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in the flowers
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most angiosperms reproduce how?
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sexually
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sexual reproduction...define
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produces new gene combinations and diverse phenotypes
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asexual reproduction...define
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produces clones of genetically identical individuals
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examples of asexual propagation
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strawberries
potatoes bananas navel oranges |
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examples of sexual reproduction (from seeds)
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wheat
rice corn soybean |
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carpels
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female sex organs
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pistil
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>1 carpel
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stamens
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male sex organs
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petals
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make up the corolla
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corolla
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made up with petals
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sepals
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make up calyx
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calyx
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small green "leaves" below petals... made of up sepals
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name parts
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gametophyte
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haploid (n) phase that produces gametes
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what does female gametophyte develop in?
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megasporangium
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what does male gametophyte develop in?
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microsproangia
|
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alternation of generations
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multicellular diploid generations (2n) alternates with a multicellular haploid generation (n)
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diploid (2n) generation
what is this called and what does it do? |
sporophyte
it produces flowers |
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flowers produce what?
|
haploid spores (n)
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spores develop into what?
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into the haploid gametophyte (n) generation
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megagametophytes develop in....
|
female
develop in megasporangia - embryo sacs |
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megasporangia are where what happens?
|
megagametophytes develop in
female embryo sacs |
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microgametophytes develop in....
|
male
develop in microsporangia - pollen grains |
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microsporangia are where what happens?
|
microgametophytes develop in these
male pollen grains |
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what is not required for transfer of pollen from anther to stigma
|
water is not required
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name 2 types of transfer of pollen from anther to stigma
|
1. self pollination
2. cross pollination |
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self pollination
|
when plants fertilize themselves
ex - peas - occurs before flower opens |
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cross pollination
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pollen is transfered to a different individual
|
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mechanisms of pollination
|
1. wind (spring - allergies)
2. water (pollinate aquatic plants) 3. animals (insects, birds, bats) |
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self incompatibility
what are advantages? what gene? |
when plants reject their own pollen
- promotes outcrossing between different genotypes - S gene - many alleles - if S allele in pollen matches either S allele in pistil, the pollen grain fails to grow |
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what happens after compatible sperm lands?
- where is sperm delivered? |
germination occurs
- growth of a pollen tube - sperm delivered to the ovule? |
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germination
|
when compatible sperm lands and pollen tube grows
|
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pollen tube - where does it grow and go?
|
grows through the megasporangium and reaches the embryo sac
|
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waht travels down pollen tube?
and what happens to it? |
generative cell
- divides into two haploid sperm cells through miotic divsion |
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were do sperm enter after pollen tube?
|
both sperm cells enter a synergid, which degenerates and releases the sperm cells
|
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what fertilization characteristic is that of angiosperms?
|
double fertilization
- two nuclear fusion events |
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what happens to two sperms?
|
- one fuses with the egg cell, forming a diploid zygote - divides mitotically to produce the sporophyte embryo
- other sperm fuses with the two polar nuclei forming a tripoid nucleus - divides by mitosis to form the nutritive endosperms (popcorn) |
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sporophyte embryo
|
one sperm fuses to form this
|
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endosperm (popcorn)
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one sperm fuses with polar nuclei forming a triploid nucleus (surrounds embryo - popcorn)
- accumulates starch, lipids, proteins |
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what physical characteristic is seen in the development of eudicots?
|
heart shaped embryo
|
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what happens to cotyledons in seeds?
|
- some absorb nutrients from the endosperm and become much larger than the embryo (kidney bean)
- some remain thin, and use nutrients from the endosperm during germination (castor bean) |
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what do seeds do during development to ensure survival
|
in later stages of development, the seed loses water and becomes dormant
|
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integuments - define and what does it develop into?
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tissues surrounding the megasporangium - develop into the seed coat
|
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carpel - what does it develop into?
|
becomes the wall of the fruit that surrounds the seed
|
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fruit - describe what consists of
|
may contain only mature ovary and seeds or include other structures
|
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name 4 ways fruits facilitate seed dispersal in 4 ways
|
1. water dispersal (coconuts)
2. animals (hide adn eat) 3. wind (parachute) 4. hitchhiking (on animals) |
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vegetative growth - what happens
|
apical meristems continuously produce leaves, stems, and axillary buds
- indeterminate growth |
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indeterminate growth
|
vegetative growth
|
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determinate growth
|
if an apical meristem becomes an inflorescence meristem it produces bracts and new meristems in the angle between bract and stem
|
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inflorescence meristems
|
give rise to floral meristems, bracts, and more inforescence meristems
|
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floral meristems
|
gives rise to a flower
|
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bract
|
modified usually reduced, leaflike structure
|
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what gives rise to a flower
|
floral meristems
|
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what gives rise to floral meristems, bracts, and more inflorescence meristems
|
inflorescence meristems
|
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what triggers transition to the flowering state
|
environmental cues
|
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name three types of flowering plants
|
1. annuals
2. biennials 3. perennials |
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annuals
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complete life cycle in one year
- ex daisy, tomatoes |
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biennials
|
complete life cycle in two years
- parsnips, carrots |
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perennials
|
live for several to many years
- oak tree |
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control of flowering and other responses by length of day or night
|
photoperiodism
|
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photoperiodism
|
control of flowering and othe responses by length of day or night
|
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name example - experiment for photoperiodism
|
1920's mutant tobacco plants
- plants would not flower until day length was shorter than 14 hours - critical day length |
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critical day length
|
length of day that is required for plant to flower
|
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short day plants (SDPs)
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flower when the day is shorter than a critical maximum.
- flower in late summer or fall ex - mums, maryland tobacco |
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long day plants (LDPs)
|
flower when the day is longer than a critical maximum.
- flower in midsummer ex. - spinach, clover |
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short-long-day plants
|
must experience short days flollowed by long days to flower
- spring (or just before mid-summer) ex - white clover |
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long-short-day plants
|
plants must experience long days followed by short days
- bloom in fall |
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critical day length
|
length of day that is required for plant to flower
|
|
short day plants (SDPs)
|
flower when the day is shorter than a critical maximum.
- flower in late summer or fall ex - mums, maryland tobacco |
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long day plants (LDPs)
|
flower when the day is longer than a critical maximum.
- flower in midsummer ex. - spinach, clover |
|
short-long-day plants
|
must experience short days flollowed by long days to flower
- spring (or just before mid-summer) ex - white clover |
|
long-short-day plants
|
plants must experience long days followed by short days
- bloom in fall |
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why is photoperiodism important
|
synchronizes flowering in the same species so that cross-pollination and successful reproduction is promoted
|
|
day-neutral plant
|
more common than photoperiodic plants - rely on other cues
|
|
what season do these flower?
1. short-long-day plants 2. long-day plants 3. short-day plants 4. long-short-day plants |
1. spring
2. summer 3. fall 4. fall |
|
do photoperiodic plants measure day or night? how do we know?
|
measure night
- experiment in 1920s with cockleburr (SDP) plants day/night time varied while other held constant - didn't matter day, but night had to be longer than 9 hours (critcal night length) |
|
critical night length
|
hours of night that had to be experienced by plant to flower
- cockleburr - 9 hours of night - hypothesis was wrong - "short day plants measure day length" |
|
what happens if niterruption occured during dark period
|
nullified the effect of a long night
|
|
phytochrome
|
plant pigment
|
|
how could red light interrruptions be reversed
|
- far-red light - indicating a plant pigmen (phytochrome) was the receptor
|
|
circadian rhythms
|
all eukaryote cells, and some prokaryotes, have a "biological clock" that oscillates between two states every 12 hours
|
|
period
|
length of one cycle
|
|
amplitude
|
magnitude of change
|
|
all circadian rhythms
|
1. period is insensitive to temp, but lowering temp may reduce the amplitude
2. highly persistent - may persist for days even in darkness 3. can be entrained - chagned to match cycles other than 24 hour cycle 4. brif exposure to light can shift the peak of the cycle (phase shift) |
|
phase shift
|
shift the peak of the cycle
|
|
give example of plant showing circadian rhythm
|
clover leaflets - folded at night, unfold during the day
|
|
night flowering
|
- flowers open when expected to get pollinated - night flowering plants pollinated by nocternal animals like bats and moths
|
|
circadian rythms must confer...
|
selective advantage
- research suggests that the advantage is the coordination of gene expression with the daily light-dark cycle - ex. chlorophyll is not produced in teh dark |
|
does the circadian clock help a plant interact with its environment?
- use experiment in answer |
hypothesis " plants fix more carbon photo-sythetically when their circadian clock matches the environments light-dark cycle
- 2 mutant plants - one with long-cycle rythm, one with short-cycle conclusion - "each mutant performed best under the cycle that corresponded to its geneticlaly determined circadian rhythm |
|
phytochromes - what does this word mean (phyto? chrome?)
|
plant color
|
|
what interact with the plants biological clock
|
phytochromes and blue-light receptors interact with the plants biological clock
|
|
explain leaves measureing light/dark experiement
|
hypothesis "the leaves measure the dark period"
- masked one leaf - flowered -masked one leaf and all plants flowered (when grafted together) |
|
give examples of plants controlled by temp
|
wheat
rye have two types of flowering behavior: annual and biannual - spring wheat is annual - winter wehat is biennial - planted in fall and flowers in sping |
|
winter wheat
|
biennial - must be exposed to cold in its first year ot it will not flower the second
|
|
induction of flowering by low temperatures
|
vernalization
- it inhibits expression of a gene whose protein product represses other genes for flower development |
|
asexual reproduction
|
produces a clone of progeny, genetically identical to the parent
- if well adapted to its environment, asexual reproduction can preserve and spread that successful genotype |
|
advantages to asexual reproduction
|
1. not reliant on weather to bring pollen
2. not reliant on other plants nearby 3. happen quickly in good conditions 4. produces offspring more likely to mature |
|
vegetative organs
|
stems, leaves, roots
|
|
what makes asexual vegetative reprodution possible
|
modification of vegetative organs
ex - strawberries - runer or stolons - develop into new plants |
|
give example of vegetative reproduction
|
runners - strawberries
tip layers - blackberry tubers - potatoes rhizomes - bamboo suckers - aspen tree plantlets bulb - onion |
|
tip layers
|
branches that sag to the ground and a new plant grows from the branch tip
|
|
vernalization
|
induction of flowering by low temperatures
- it inhibits expression of a gene whose protein product represses other genes for flower development |
|
rhizomes
|
horizontal underground stems that give rise to new shoots
ex. bamboo |
|
bulbs
|
also known as corms
- short , vertical underground stems - have fleshy, modified leaves for food storage - a large, underground bud. these can give rise to new plants (lilies, onions) |
|
suckers
|
shoots produced by roots. many grasses and trees, such as aspens form interconnected stands of genetically identical individuals
|
|
where do asexual plants traditionally live
give example |
unstable environments
- ex plants with stolons and rhizomes pioneers of sand dunes (beach grasses) rapid reproduction allows them to survive shifting in sangs, and their roots help stabalize the dune |
|
vegetative reproduction - disadvantages
example |
all the same - so one virus or disease could wipe out all
- dutch elm disease (no genetic diversity to fight disease) |
|
where is vegetative reproduction used
- how? |
in agriculture
- stem cuttings inserted into soil will often grow into a new plant, especially if treated with auxin |
|
grafting
|
root bearing plant is the stock
part grafted on is scion vascular cambia of each must grow together so that water and minerals can be transported to the scion - usually closely related species |
|
scion
|
part grafted
|
|
stock
|
root bearing plant
|
|
totipotent
|
undifferentiated cells
|
|
name ways totipotent cells are important
|
1. researchers are investigating ways to reproduce plants by tissue culture
2. culturing tiny bits of apical meristem can eliminate plant viruses |
|
how have we used asexual plants to modify our produce
|
treatment with hormones can cause apical meristmes to produce millions of plants a year
produce virus-free, frost-resistant, increased nutritive value ex. strawberries frost resistant- now plant wont die with early frost |
|
plants ways to adapt to harsh environment
|
1. desert - self amputation
2. strangling fig in jungle 3. carnivorous plants - need nitrogen and can't get from soil |
