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116 Cards in this Set
- Front
- Back
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cladogram
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tree showing evolutionary relationships
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cladistics
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classification system based on historical sequence of divergence (phylogeny)
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homology
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characteristics shared within a group that are unique to that group since it derived from a common ancestor (homology = synapomorphy)
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synapomorphy
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shared, derived character
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monophyletic group
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natural evolutionary group descended from a common ancestor
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parallel evolution
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two groups developed same structure, but have no common ancestor.
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analogy
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has functional, but not necessarily evolutionary, background (bat & bird wings)
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outgroup comparison
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comparison with a group that lies outside of the group being studied
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structural homology
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same structure and arrangement, but different function (human arm & dolphin flipper)
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transitional homology
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a certain structure develops a new function over time (hyomandibular in fish eventually becomes free to develop into stapes in human ear)
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serial homology
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structures in an individual develop in a series (vertebrate in an organism are homologous)
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natural selection
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individuals with favorable traits survive and reproduce to pass on those favorable traits to future generations. Process by which evolution occurs.
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artificial selection
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intentional breeding for certain traits\
1) Variation: cause by mutation 2) Heritable 3) More offspring born than survive 4) Reproduction & survival are NOT RANDOM |
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evolution summary
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genotypes & phenotypes shift in certain direction in accordance with changing environment. ultimate goal = to pass genes on to future generations
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heterochromy
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change in developmental timing between reproductive & somatic structures (paedomorphosis)
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paedomorphosis
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looks like a juvenile, but has reproductive capabilities.
1) progenesis: accelerated development of reproductive organs 2) neoteny: delayed somatic development |
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ambystoma (salamander)
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example of heterochromy
1) low lands (good conditions) - showed normal metamorphosis 2) high lands (low oxygen, etc.) - reproduced while still in pond = more variation than low lands |
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chordata
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1) notochord - vertebral column
2) dorsal hollow nerve chord 3) gill slits must have all of these characteristics, but don't need them all at once |
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Evidence for Evolution
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1) Diversity - variation of life forms
2) Adaptable - able to acclimate to changing conditions |
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Theory of Special Creation
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1) species do not change
2) each species created separately 3) earth & life are young |
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Decent with Modification
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1) species change over time
2) species derive from common ancestor 3) earth & life are old |
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Evidence for Evolution (specific examples)
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1) HIV mutations
2) co-evolution: birds & flowers change in response to one another 3) Soapberry bug: orig long beak to pierce fruit of balloon vine, but developed shorter beak when thin fruit of flat-podded golden rain tree introduced |
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vestigial organ
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organ that once had a use remains in an organism without any current use (ex. appendix, coccyx, etc) Shows common ancestry
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Pseudogenes
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false (non-coding) genes
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coding gene
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under influence of stabilizing selection
1) mutation that is detrimental (death) will be selected out 2) neutral mutations can hang around for a while |
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Fossil Record
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proves extinction; biota change (change in diversity)
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transitional form
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-step by step evolution/development of certain structures.
-some structures, such as eye, too complex to form in steps -Archiopteryx: transitional form between birds & reptiles |
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Keller et. al Study of Chimps
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-Studied chimps, banobos, gorillas, orangutans, & humans
-PmP-22 gene (produces melanin) -CmTiA segment at distal end of PmP-22 causes unequal crossing over -Chimps, banobos, & humans have proximal segment of CmTiA -Duplication occurred during unequal crossing over |
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Gradual Evolution
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occurred in small incremental steps leading to diversity
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punctual equilibrium
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evolution occurs in periods of rapid change/speciation with long periods of stasis in between
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Galapagos Finches
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-variation in bill shape within species
-drought during study caused short billed finches to die off because small seeds dying -large billed finches survived |
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fitness
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-ability to reproduce & survive through generations
-measured by number of individuals produced during one's lifetime) |
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reproductive potential
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-amount off individuals produced if all survive & reproduce
-no species reaches reproductive potential |
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parsimony
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-simplest explanation for an observation (Occam's Razor)
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chaos
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-complete randomness
-opposite of parsimony |
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adaptation
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-trait or combination of traits that increase fitness
-giraffes had to compete for vegetation, so giraffes with longer necks survived & reproduced 1)determines what the trait is for 2)show that individuals with trait contribute more genes than individuals w/o trait |
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Simmons et al & Young et al (giraffe hypothesis)
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thought giraffes neck is used as a weapon and to attract females
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Pratt & Anderson (giraffe data)
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-giraffes with stronger necks & heavier heads are more dominant
-females preferred these males |
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Clayton (Rock Pigeon beaks)
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-ran experiment to test hypothesis that hook on beak is used to pick off lice & parasites
-observed 26 pigeons -trimmed off hook & after 18 weeks, significant increase in live -13 allowed to grow back, significant decrease in lice |
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Greene (Tephritid Fly)
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-have stripe pattern on wings & flap wings in certain way
-performed multiple experiments to test 3 hypotheses -Conc: banding pattern & flight pattern used to avoid predation by jumping spider |
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behavioral thermoregulation of garter snakes
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-observed garter snakes to determine evening borrow choice
-Conc: preferred medium-large rocks (28-32 degrees C) |
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Evolution of Mammalian Ear
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1) establish ancestral condition
2) understand transformation series |
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morphological novelty
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develops & allows organism to exploit new resources & move into different lines of evolution
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Adaptionist Point of View (Selectionist)
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-break organism into parts & figure out adaption for each part
-combination of all adaptions = organism |
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Bauplane
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organism is an integration of parts and we must be analyzed as a whole
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Trade-off
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-one characteristic might be less optimal in order to maintain a trait that is more optimal
-more optimal for lizards to be small in terms of energy, but males are usually large because it is more optimal for defense/competition |
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Adaptationist Program
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if one adaptive argument fails, try another. if that fails, assume another must exist; a weaker version of the first argument
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Primary Adaptation
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original reason for the adaptation to occur (ex. feather primarily for insulation)
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Secondary Adaptation
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shows up through necessity (ex. feathers secondarily used for flight)
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Feathers
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Primary Adaptation - Insulation
Secondary Adaptation - Flight |
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Formation of Adaptations
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not all attributes develop to improve an organism, some develop through mutations, genetic drift, etc.
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Dr. Pangloss
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everything is optimal; everything is around for the best
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Constraint
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something that restricts possible paths & modes of change (ex mouse could never be the size of an elephant)
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Phyletic Constraints
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constrained by evolution/heritage
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Developmental Constraints
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development is limited by the phenotypes that are able to be produced
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Architectural Constraints
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in order to have a certain feature, one must have other specific traits (ex. to have dome rest on rounded arches, spandrels will also be a feature)
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Adaptation without selection
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climb a mountain = increase in RBC's, etc.
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Phenotypic Plasticity
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-phenotypes influenced by environment
-The ability of an organism with a given genotype to change its phenotype in response to changes in the environment |
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Phototactic Behavior
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-example of adaptation
(+) = move towards the light (-) = move away from the light |
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Species
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Groups of interbreeding populations that are evolutionary independent of other populations
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population
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-subset of species
-group of interbreeding individuals |
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Greek Species Concept
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unstable; spontaneous generation of species; hybridization - can breed any two animals to get something different
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Typological Species Concept
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Fixed; set stage for Linneaus (genus/species); characteristics attributed to animals (WORKING THEORY/CONCEPT)
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Biological Species Concept
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-criterion for determining evolutionary independence is reproductive isolation
-species is a reproductive community that is isolated from other groups. |
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Evolutionary Species Concept
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A species is a single lineage of ancestor-descendant populations which maintain its identity from other such lineages and which has it own evolutionary tendencies and historical fate
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Semispecies
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form after geological isolation, but not yet considered a distinct species
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divergent lineage
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1)Common Ancestor
2)Colonies A/B 3)Geographic Race A/B 4)Semispecies A/B 5)Species A/B 6)Genus A/B |
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Phylogenetic Species Concept
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-A species is the smallest diagnosable cluster of individual organisms within which there is a parental pattern of ancestry and descent
-lineage with all individuals being distinct & recognizable from other lineages |
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Allopatric Speciation
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-Geographic Isolation (most prevalent)
-slow speciation & slow reproductive isolation mechanisms (occurs after separation) |
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Vicariance
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-species gets divided by mountain, river, etc.
-can't identify ancestor |
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Founder Effect
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-Small group forms a colony somewhere else; dispersal
-can identify ancestral population |
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Reproductive Isolating Mechanisms
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-Premating: breeding time, seperate niches, physically incapable
-Postmating: zygote death, sterile hybrid |
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Sympatric Speciation
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-No geographic isolation
-speciation and RIM occur fast & before species separate |
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Parasympatric Speciation
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-occurs in organisms that are cecile
-change occurs at periphery of population as a chromosomal rearrangement |
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Species - Process
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-Moving from ancestral population
-evolution species concept, subspecies, etc. -longer they are apart = move chance of natural selection, genetic drift, etc will lead to separate species |
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Species - Working
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-tyoplogical & phylogenetic species concepts
-separated by characteristics |
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Allopatric Speciation
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-Geographic Isolation
a)vicariance b)dispersal -RIM = slow -can't determine ancestor |
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Sympatric Speciation
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-No Geographic isolation
-Mutation (change in middle of population) -RIM = fast -can identify ancestor (ex. insect/host relationship) |
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Parapatric Speciation
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-Cecile species
-Speciation occurs at periphery -Chromosomal change -most fit population settles in center -farther from center = less optimal -hybrid zone is poorly (mal) adapted and eventually diminishes |
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Reproductive Isolating Mechanisms
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-Premating: habitat, behavioral, mechanical
-Postmating: gamete mortality, zygote mortality, hybrid inviability, hybrid sterility |
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RIM = Complete
Ecological Divergence = complete |
-evolution into new species
-even after geographical barrier disappears, 2 species can't reproduce |
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RIM = complete
Ecological Divergence = Incomplete |
-compete for resources
-character displacement allows to partition environment and stop competition |
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RIM = incomplete
Ecological Divergence = Incomplete |
-able to breed
-hybrids, intergression, original population |
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Adaptive Radiation
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-evolutionary divergence of members of a single phyletic line into a series of different niches or adaptive zones (requires empty niches for movement)
-essential for evolution (leads to diversity) -adapting to environment (driven by natural selection) -usually associated with speciation |
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Extinction
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-opposite of adaptive radiation
-creates empty niches for adaptive radiation |
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Generalizations About Adaptive Radiation
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1)A shift into new ecological niche is most likely at EDGE of species range
2)Lack of competition/predators (due to open areas with good resources) 3)Islands provide empty niches 4)Occupation of a new niche or adaptive zone leads to increase in speciation and evolutionary pathways exploited |
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Taxonomic Class
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1)Increase in speciation, decrease in adaptive radiation = many species within a single genus
2)increase in adaptive radiation, decrease in speciation = many genera with few species |
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Are radiations predictable
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No, evolutionary sequences are unpredictable, but in retrospect rational
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K/T boundary
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-Cretaceus Extinction
-North: birds dominated at first (very large birds) |
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Types of Adaptive Radiation
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1)General Adaptation
2)Environmental Change 3)Archipelagos |
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General Adaptation
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-evolutionary novelty
-wing = flight -jaw = predator -structure = take advantage of new niche |
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Archipelagos
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-area of isolation; island, mountain top, etc.
-no competitors, many resources |
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Adaptive Model
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natural selection + adaptation
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Genetic Drift
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-random chance
-argued to be mechanism for adaptation & natural selection |
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Sexual Selection
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-drives speciation & adaptation
-mates selecting for certain characteristics -females choice |
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Extinction
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Every species is destined for extinction
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Background Extinction
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-extinctions that are not part of mass extinctions
-usually caused by local environmental change or species interactions, opposed to global environmental changes |
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Mass Extinction
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Large scale, wide-spread extinctions; very sudden
1)Late Ordivician 2)Late Devonian 3)Late Permian 4)Late Triassic 5)Late Cretaceous |
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Pleistocene Overkill
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-Human industrialization and expansion in causing a mass extinction
-Greater extinction rates in more populated areas (Asia & USA) -Rates are lower in less populated areas (Africa) |
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Extinction
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1)Competition: one species in out-competing another for resources
2)Environmental changes |
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Raup & Sepkowski (Mass Extinction Hypothesis)
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cyclical pattern of mass extinction caused by large body impact about every 28 million years
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Large Body Impact
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-asteroids, comets, meteorite, etc.
-Alvarez & Mueller found crater in Yucatan Peninsula -crater = 10 km in diameter -boundaries = calcareous microplankton & high iridium levels -Determined cycle to be about every 28.4 million years |
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Catastrophic Mass Extinction
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-abrupt global change
-impact caused darkness, change in temp, heat shock of atmosphere -caused N2 & O2; leads to oxides -oxides dissolve into H2O to nitric acid to acid rain -Large species (dinosaurs) could not adapt quickly |
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Stepped Mass Extinction
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-has time constraints
-specialized organisms that were sensitize to change died off first -Organisms that were able to adapt better died off later |
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Cambrian Explosion
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-Lots of diversity
-within 40 million years every phyllum represented -evidence in fossil record (incomplete/difficult to age fossils) |
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Cambrian Explosion
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-diversity
1)diploblasts (2 embryonic cell types) --> triploblasts (mesoderm = heart, gonads, and connective tissue) 2)Coelomates vs. psuedocoelomates vs. acoelomates 3)Protosomes (blastopore becomes mouth & anus) vs. Deuterostomes (blastopore becomes anus + seperate mouth) |
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Coelomate
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-true body cavity from mesoderm
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Psuedocoelomate
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-body cavity not lined with mesoderm
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acoelomate
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-no body cavity
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Molecular Data
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Molecular clock: times of divergence based on how different something is (ex. hemoglobin)
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Ecology Changes
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1) Increase in O2 = seawater photosynthesis through evolution of plants
Increase in O2 = increased diversity (gills, lungs, etc.) 2)Hard Parts: Jellyfish --> arthropods (variation caused by mutation) |
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Oparin/Haldane Model
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-simple -->complex
-Inorganic early Earth --> amino acids, nucleotides, building blocks --> polymers --> proteins (large organics) --> structure (membranes, etc.) |
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Energy Sources
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1)Inorganic Molecules: methanobacteria -->reduce CO2 --> energy + methane
2)Organic Molecules: Fermentation (O2 free environment) C6H12O6 --> 2CO2 + 2CH3CH2OH + Energy (2 ATP) -Eventually photosynthesis evolved in algae CO2 + H2O --> C6H12O6 + O2 (aerobic) -Photosynthesis + O2 = key to complexity -Respiration: C6H12O6 + O2 --> CO2 + H2O + E |
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Endosymbiotic Theory
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1)Invasion of a large cell (mycoplasm) by purple bacteria (mitochondria) w/ respiratory capability --> symbiotic relationship (respiration/protection)
-digenomic: contains genes of 2 organisms 2)Undulopodia (flagellum) -spirochetes: prokaryote w/ undulopodia 3)Choloroplast: cyanobacteria capable of photosynthesis combine w/ cell capable of respiration --> trigenomic cell -Mitochondrial & choloroplast genes sequenced & small unit of rRNA compared -mitochondira & purple bacteria = identical -chloroplast & cyanobacteria = identical -Margulis cladogram is two combining to one |
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Edicarian Fauna
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-Area of fossilization in Southern Australia (565 - 544 mbp)
-Soft bodied organisms --> leave impression in rock -Sponges, Jellyfish, combjellies --> all diploblasts |
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Burgese Shale Fauna/Yunnan Province Fauna
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-Burgese Shale (520-515 mbp)
-Yunnan Province (525-520 mbp) -arthropods --> triploblasts -segmented worms -mollusks -jawless fish |
