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65 Cards in this Set
- Front
- Back
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There were originally ____ species of cichlids.
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500
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Where were the species of cichlids located?
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Lake Victoria
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organisms that can breed and produce fertile offspring
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species
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The _____ frequencies in any population have the tendency to change due to genetic drift and some of the other concepts.
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allele
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If genetic drift (or the other concepts) goes on long enough, the groups may not be able to ______ any longer and you end up with different ______.
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interbreed, species
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______ prevents gene flow (prevents alleles from moving back and forth between the two populations and eventually they become so different that they are actually different species) and maintains separate species.
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Reproductive isolation
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Two closely related species of cichlid _____ at different depths.
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feed
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The males of two species of cichlid differ in _______.
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color
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Females of each species prefer _______ males.
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brightly colored males with the "right" color
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Healthy color in cichlids indicates the overall ______ of the individual.
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health. If the mate is healthy, there is a better chance of passing on the genes of the parents into the next generation.
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Over the last 30 years, ___ species of cichlids have disappeared.
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200
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What was an introduced predator in Lake Victoria that has ate some of the cichlids?
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Nile perch
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Another reason that species of cichlids could be disappearing is that in polluted water, ____ is hard to detect.
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color, Therefore, females may not be choosing the brightest colored males because they can't detect them, so some of those groups that were previously isolated may be mixing more and becoming more similar, instead of more distinct. So gene pools of 2 species are mixing.
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the emergence of new species
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speciation
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Every time speciation occurs, the ______ of life increases.
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diversity
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The many millions of species on Earth have all arisen from an __________ form that lived around ______ years ago.
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ancestral life, 3.6 billion
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the branch of biology that names and classifies species and groups them into broader categories
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Taxonomy
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Carolus Linnaeus developed the _______ system, which requires that you have a ____ and a _____, of naming organisms using physical characteristics to distinguish over 11,000 species.
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binomial, genus, species
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Similarities between some species and variation within species can make defining species difficult.
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note
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a group with the potential to interbreed in nature and produce fertile offspring
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biological species
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ways to classify species
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taxonomy, morphology, ecological species, phylogenetic species
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Morphology classifies based on ______ traits.
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phenotypic (traits that are expressed, that you can observe)
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Morphology works on ______ organisms, ______, and when we don't know if _______ is possible. It is also ______.
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asexual, fossils, interbreeding, subjective
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species defined by ecological role or niche (how the organism functions, where it lives, where it's ecological position is, and its relationship with other organisms around it)
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ecological species
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organisms with a specific inherited lineage
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phylogenetic species
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________ or _______ can be used to define a species.
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Morphology, DNA
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Problem: Defining the amount of difference needed to distinguish a species
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note
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___________ serve to isolate a species gene pool and prevent interbreeding.
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Reproductive barriers
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Reproductive barriers are categorized as ________ or ________.
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prezygotic, postzygotic
- depending on whether they function before or after zygotes form |
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_______ barriers prevent mating or fertilization.
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Prezygotic
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What do prezygotic barriers prevent?
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mating or fertilization
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types of prezygotic barriers
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Temporal isolation, Habitat isolation, Behavioral isolation, Mechanical isolation, Gametic isolation
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The type of barrier that affects the timing of mating event?
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temporal isolation
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The type of barrier that occurs with populations that don't live in the same place?
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habitat isolation
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The type of barrier that occurs when organisms are not attracted to each other?
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behavioral isolation
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The type of barrier where there are structural differences in the organisms that prevent them from transferring genetic information?
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mechanical isolation
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The type of barrier that occurs when male or female gametes die before they can achieve fertilization?
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gametic isolation
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________ Barriers prevent the development of fertile adults.
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Postzygotic
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What do postzygotic barriers prevent?
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the development of fertile adults
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Examples of postzygotic barriers?
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reduced hybrid viability, reduced hybrid fertility, hybrid breakdown
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Hybrids fail to develop or to reach sexual maturity (a type of postzygotic barrier)
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reduced hybrid viability
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Hybrids may not produce eggs and sperm that can actually function or achieve fertilization (a type of postzygotic barrier)
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reduced hybrid fertility
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The offspring of hybrids are weak or infertile (a type of postzygotic barrier)
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hybrid breakdown
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In ________ isolation, there is little or no sexual attraction between species, due to specific behaviors
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behavioral
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In _______ isolation, female and male sex organs are not compatible
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mechanical
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In ______ isolation, female and male gametes are not compatible
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gametic
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______ barriers operate after hybrid zygotes are formed.
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Postzygotic
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In _______________, most hybrid offspring do not survive (type of postzygotic barrier)
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reduced hybrid viability
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In ________________, hybrid offspring are vigorous but sterile (type of postzygotic barrier)
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reduced hybrid fertility
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In _____________, the first-generation hybrids are viable and fertile, but the offspring of the hybrids are feeble or sterile (type of postzygotic barrier)
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hybrid breakdown
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The process of speciation depends on whether whether ______ barriers prevent ______ between populations
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reproductive, gene flow
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populations of the same species are geographically separated, separating their gene pools
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allopatric speciation
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Changes in the allele frequencies of each population may be caused by ________, _______, and ________ (which can can upset Hardy-Weinberg equilibrium), unaffected gene flow from other populations
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natural selection, genetic drift, mutation
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Allopatric speciation depends on the organism as well, river might separate an organism that can't swim, but it might not be wide enough to separate a population of organisms that can fly or swim -> large rivers, mountains
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Note
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Gene flow between populations is initially prevented by a _______ barrier.
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geographic
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In ______ speciation, speciation takes place without geographic isolation.
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sympatric
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new species may arise within the same geographic area as a parent species
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sympatric speciation
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Gene flow between populations may be reduced by factors such as .....
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polyploidy (in plants), habitat differentiation (different groups in a population start utilizing different habitats), sexual selection
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the multiplication of the chromosome number due to errors in cell division
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polyploidy
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Many plant species have evolved by _______.
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polyploidy
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A ________ (4n) plant can arise from a diploid parent.
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tetraploid
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Peter and Rosemary Grant have studied medium ground finches on tiny, isolated, uninhabited __________ in the ______ Islands for 35 years.
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Daphne Major, Galapágos
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Medium ground finches and cactus finches occasionally ______.
- Hybrid offspring have _______ bill sizes and survive well during ____ years, when there are plenty of soft, small seeds around. - During ____ years, hybrids are outcompeted by both parental types (can do better with extreme seed sizes). |
interbreed, intermediate, wet, dry
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The occasional hybridization between finch species introduces new ____ in both populations.
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genes
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During drought years, _____ die out. (finches)
- This keeps medium ground finches and cactus finches on separate evolutionary paths. |
hybrids
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