Term
| theory of special creation |
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Definition
species are independent
life is young (6000 years)
species do not change |
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Term
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Definition
species are unchanging
variations are unimportant/misleading |
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Term
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Definition
species are fixed
some species are higher than others |
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Term
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Definition
organisms evolve to become more complex
inheritance of acquired characters |
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Term
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Definition
| individuals of same species that are living in same area at same time |
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Term
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Definition
| Darwin- variation was key to understanding nature of species |
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Term
| pattern component of natural selection |
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Definition
1. species change through time
2. species are related by common ancestry |
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Term
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Definition
| any trace of an organism that lived in the past |
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Term
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Definition
| all fossils that have been found and described in scientific literature |
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Term
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Definition
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Term
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Definition
4.6 billion years (geologic record)
life- 3.4-3.8 billion years |
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Term
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Definition
trait in a fossil species that is intermediate between those of older and younger species
ex: fins to limbs |
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Term
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Definition
reduced or incompletely developed structure that has no function or reduced function, but is similar to a functioning structure in a closely related species
ex: human coccyx |
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Term
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Definition
| family the of populations or species |
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Term
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Definition
| similarity that exists in species because they both inherited the trait from a common ancestor |
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Term
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Definition
occurs in DNA sequences
ex: eyeless gene in fruit flies and Aniridia gene in humans are 90% identical in amino acid sequence |
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Term
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Definition
recognized in embryos
ex: chick, human and cat embryos have tails and gill pouches |
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Term
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Definition
similarity in adult morphology (form)
ex: common structural plan in limbs of vertebrates |
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Term
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Definition
| process that results in one species splitting into two or more descendant species |
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Term
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Definition
| observation that data from independent sources agree in supporting predictions made by a theory |
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Term
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Definition
| change in allele frequencies in a population over time |
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Term
| shortened four postulates |
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Definition
| evolution by natural selection occurs when 1) heritable variation leads to 2) differential reproductive success |
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Term
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Definition
| ability of an individual to produce surviving offspring, relative to that ability in other individuals in population |
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Term
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Definition
variation exists
variation is heritable
variation in reproductive success
selection occurs |
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Term
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Definition
| allows researchers to compare treatment groups created by an unplanned change in conditions |
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Term
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Definition
| many genes influence a trait |
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Term
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Definition
| changes in an individual's phenotype that occur in response to changes in environmental conditions |
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Term
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Definition
| occurs when a single allele affects multiple traits |
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Term
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Definition
| compromise between tats, in terms of how those traits perform in the environment |
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Term
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Definition
| increases frequency of certain alleles |
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Term
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Definition
causes allele frequencies to change randomly
random with respect to fitness
most pronounced in small populations
can lead to random loss or fixation of alleles over time |
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Term
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Definition
occurs when individuals leave one population, join another and breed
equalizes allele frequencies between the two populations |
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Term
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Definition
| modifies allele frequencies by continually introducing new alleles |
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Term
| four mechanisms that shift allele frequencies |
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Definition
natural selection
genetic drift
gene flow
mutation |
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Term
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Definition
| all of the gametes produced in each generation |
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Term
| Hardy-Weinberg assumptions |
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Definition
| none of the four mechanisms of evolution are occurring, random mating is occurring |
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Term
| Hardy-Weinberg assertions |
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Definition
p^2, 2pq, q^2
allele frequencies do not change over time |
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Term
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Definition
| number and relative frequency of alleles that are present in a particular population |
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Term
| types of natural selection |
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Definition
directional selection
stabilizing selection
disruptive selection
balancing selection |
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Term
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Definition
| average phenotype of a population changes in one direction |
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Term
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Definition
| when disadvantageous alleles decline in frequency |
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Term
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Definition
| no change in average value of a trait over time and genetic variation in population is reduced |
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Term
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Definition
| eliminates phenotypes near the average value and favors extreme phenotypes |
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Term
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Definition
no single allele has a distinct advantage and increases in frequency
there is a balance among several alleles in terms of their fitness and frequency |
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Term
| frequency-dependent selection |
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Definition
| certain alleles are favored when they are rare, but not when they are common |
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Term
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Definition
| change in allele frequencies due to blind luck |
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Term
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Definition
| specific allele that causes a distinctive phenotype |
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Term
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Definition
| change in allele frequencies that occurs when a new population is established |
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Term
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Definition
| sudden reduction in number of alleles in a population |
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Term
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Definition
| alleles that lower fitness |
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Term
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Definition
| allows individuals to produce more offspring |
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Term
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Definition
mating between relatives
does not cause evolution |
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Term
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Definition
| changes genotype frequencies, not allele frequencies |
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Term
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Definition
| decline in average fitness that takes place when homozygosity increases and heterozygosity decreases in a population |
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Term
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Definition
based on success in courtship
special case of natural selection |
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Term
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Definition
| any trait that differs between males and females |
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Term
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Definition
| an evolutionarily independent population or group of populations |
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Term
| criteria for identifying species |
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Definition
biological species concept
morphospecies concept
phylogenetic species concept |
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Term
| biological species concept |
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Definition
| states that the critical criterion for identifying species is reproductive isolation |
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Term
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Definition
| prevents individuals of different species from mating |
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Term
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Definition
| offspring of matings between members of different species do not survive or reproduce |
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Term
| temporal prezygotic isolation |
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Definition
| populations are isolated because they breed at different times |
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Term
| habitat prezygotic isolation |
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Definition
| populations are isolated because they breed in different habitats |
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Term
| behavioral prezygotic isolation |
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Definition
| populations do not interbreed because their courtship displays differ |
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Term
| gametic barrier prezygotic isolation |
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Definition
| matings fail because eggs and sperm are incompatible |
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Term
| mechanical prezygotic isolation |
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Definition
| matings fail because male and female reproductive structures are incompatible |
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Term
| hybrid viability postzygotic isolation |
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Definition
| hybrid offspring do not develop normally and die as embryos |
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Term
| hybrid sterility postzygotic isolation |
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Definition
| hybrid offspring mature but are sterile as adults |
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Term
| biological species concept disadvantages |
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Definition
cannot be evaluated in fossils or species that reproduce asexually
difficult to apply when closely related populations do not overlap geographically |
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Term
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Definition
| evolutionarily independent lineages are identified by differences in size, shape, or other morphological features |
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Term
| morphospecies concept disadvantages |
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Definition
cannot identify cryptic species
morphological features used to distinguish species are subjective |
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Term
| phylogenetic species concept |
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Definition
| species are identified as smallest monophyletic groups on phylogenetic tree |
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Term
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Definition
a.k.a. clade or lineage
consists of an ancestral population, all of its descendants, and only those descendants |
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Term
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Definition
| trait found in certain groups of organisms that exists in no others |
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Term
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Definition
| inherited form a common ancestor |
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Term
| phylogenetic species concept disadvantage |
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Definition
| carefully estimated phylogenies are available only for a tiny (though growing) subset of populations on the tree of life |
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Term
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Definition
| populations that live in discrete geographic areas and have distinguishing features but are not considered distinct enough to be called separate morphospecies |
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Term
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Definition
| population separates into a new habitat, colonizes it, and founds a new population |
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Term
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Definition
| physical splitting of a habitat |
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Term
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Definition
| speciation that begins with physical isolation via either dispersal or vicariance |
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Term
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Definition
| when populations live in different areas |
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Term
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Definition
| study of how species and populations are distributed geographically |
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Term
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Definition
| groups are each other's closest relatives |
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Term
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Definition
| genetic isolation accompanied by genetic divergence due to mutation, selection, and genetic drift |
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Term
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Definition
| when populations or species live in the same geographic area, or at least close enough to one another to make interbreeding possible |
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Term
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Definition
| speciation that occurs even though gene flow is possible |
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Term
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Definition
| having more than two sets of chromosomes |
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Term
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Definition
| individuals rarely produce fertile offspring when they mate, so tetraploid and diploid populations are reproductively isolated |
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Term
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Definition
| individuals are produced when a mutation results in a doubling of chromosome number and chromosomes all come from same species |
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Term
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Definition
| individuals are created when parents that belong to different species mate and produce an offspring where chromosome number doubles |
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Term
| why polyploidy is common in plants |
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Definition
sister chromatids do not always migrate to opposite poles properly
self-fertilization makes it possible for diploid gametes to fuse
hybridization is common |
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Term
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Definition
| fast, sympatric, and common |
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Term
| possibilities when isolated populations come into contact |
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Definition
| reinforcement, hybrid zones, and speciation by hybridization (fusion of populations, extinction of one population) |
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Term
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Definition
| natural selection that supports differences that evolved while populations were isolated from one another |
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Term
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Definition
| geographic area where interbreeding occurs and hybrid offspring are common |
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Term
| mechanisms of sympatric speciation |
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Definition
| disruptive selection, polyploidization |
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Term
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Definition
| evolutionary history of a group of organisms |
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Term
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Definition
| shows ancestor-descendant relationships among populations or species and clarifies who is related to whom |
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Term
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Definition
| represents a population through time |
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Term
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Definition
point where two branches diverge
represents point in time when an ancestral species split into two or more descendant species |
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Term
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Definition
endpoint of a branch
represents a group (a species or larger taxon) that is living today or ended in extinction |
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Term
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Definition
based on computing a statistic that summarizes overall similarity among populations based on data
ex: using gene sequences |
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Term
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Definition
| based on realization that relationships among species can be reconstructed by identifying shared derived characters in species being studies (synapomorphies) |
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Term
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Definition
| characteristic that existed in an ancestor |
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Term
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Definition
| characteristic that is a modified form of an ancestral trait |
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Term
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Definition
| occurs when traits are similar due to shared ancestry |
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Term
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Definition
| occurs when traits are similar for reasons other than common ancestry |
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Term
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Definition
| occurs when natural selection favors similar solutions to problems posed by a similar way of making a living |
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Term
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Definition
| if similar traits found in distantly related lineages are due to common ancestry, then the traits should be four in intervening lineages |
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Term
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Definition
| most likely explanation or pattern is the one that implies the least amount of change |
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Term
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Definition
| species or group that is closely related to a monophyletic group but is not a part of it |
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Term
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Definition
short interspersed nuclear elements
parasitic gene sequences which occasionally insert themselves into genomes of mammals |
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Term
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Definition
| piece of physical evidence from an organism that lived in the past |
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Term
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Definition
| total collection of fossils that have been found throughout the world |
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Term
| limitations of fossil record |
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Definition
| habitat bias, taxonomic and tissue bias, temporal bias, and abundance bias |
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Term
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Definition
| organisms that live in areas where sediments are actively being deposited (beaches, mudflats, swamps) are much more likely to form fossils than organisms living in other habitats |
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Term
| taxonomic and tissue bias |
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Definition
| organisms with hard parts (bones, shells) are more likely to decay slowly and leave fossil evidence |
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Term
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Definition
| recent fossils are much more common than ancient fossils |
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Term
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Definition
| organisms that are abundant, widespread, and present on Earth for long periods of time leave evidence much more than do species that are rare, local, or ephemeral |
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Term
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Definition
| scientists who study fossils |
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