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Definition
| theory that said higher being created separate forms of life. species cannot change. |
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| descent with modification |
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| Darwin's idea that species come from those before and change over generations |
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| a fossil species with traits that are intermediate between old and young species. |
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| reduced or incompletely developed traits that have no function but are similar to other functioning structures in other species |
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| morphological traits that are similar between species |
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developing embryos of different species are structurally similar
a)morphology is similar
b)fate of embryonic tissue is similar |
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| similarities in genetic sequencing (DNA) |
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| similar traits that are similar because of environment and not because they share common ancestors |
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| occurs when natural selection favors similar solutions to problems posed by a similar way of making of living |
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1. vary in traits
2. heritable
3. some individuals produce more than others
4. individuals with certain traits are more like to produce |
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| ability to produce offspring - measureable |
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| heritable trait that increases fitness |
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| change in allele frequency in a population and thus it's genetic makeup. |
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| occurs when an individual changes in response to a change in environmental conditions |
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Definition
| selection on alleles for one trait caused a correlated, though suboptimal, increase in another trait. |
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| a group of individuals from the same species that live in the same area and regularly interbreed |
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| mechanisms that shift allele frequencies |
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Definition
1. natural selection
2. mutation
3. genetic drift
4. gene flow |
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Term
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Definition
| causes allele frequencies to change randomly. may cause alleles that decrease fitness to increase in frequency |
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Definition
| occurs when individuals immigrate into or emigrate from a population. arriving individuals introduce alleles to their new population and emigrating individuals remove alleles from their old populations |
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| continually introducing new alleles. the alleles created by mutation may be beneficial, detrimental, or have no effect on fitness. |
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Definition
| all the gametes produced in each generation go into a single group - gene pool |
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| when heterozygotic individuals have higher fitness than homozygous individuals, natural selection maintains genetic variation in the population. |
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| refers to the number and relative frequency of alleles that are present in a particular population |
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Definition
| allele frequencies change in one direction |
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Definition
| reduces the amount of extremes in a population. there is no change in the aerage value of a trait over time, and genetic variation in the population is reduced. |
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Definition
| eliminates phenotypes near the average value and favors extreme phenotypes. |
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Definition
| the formation of new species |
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Definition
occurs when individuals within a population differ in their ability to attract mates
1. male-male competition
2. female selection |
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Definition
| a claim about a pattern in the natural world and a mechanism that causes the pattern |
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| fundamental asymmetry of sex |
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Definition
1. females produce relatively few young. it costs more energy for the female to rear young.
2. sperm are simple to produce |
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Definition
| any trait that differs between males and females in the same species. |
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| allele frequencies change due to blind luck |
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Definition
| a specific allele that causes a distinctive phenotype |
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Definition
| sudden reduction in the number of alleles in a population |
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Definition
| when a group of individuals emigrates to a new geographic area and founds a new population |
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| change in allele frequencies that occurs when a new population is established |
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| allels that lower fitness |
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Definition
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Term
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Definition
loss of fitness that takes place when homozygosity increases and heterozygosity decreases
1. recessive alleles represent a loss of function mutations.
2. many genes - especially those involved in fighting disease - are under intense selection for heterozygote advantage. if an individual is homozygous at these genes,then fitness declines. |
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Term
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Definition
| identify independent lineages by difference in size, shape, or other morphological features. |
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Term
| phylogenetic species concept |
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Definition
reconstructing the evolutionary history of populations and is increasingly popular among biologists.
1. can be applied to any population.
2. it is logical because populations are monophyletic only if they are independent of one another and isolated from gene flow. |
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Definition
| consists of an ancestral population and all of its descendants and only those descendents. |
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| populations that have distinguishing features, but not distinct enough to be called a separate species. |
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| physical splitting of habitat |
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| speciation that begins with physical isolation via either dispersal or vicariance |
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| populations that live in different areas |
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| the study of how species and populations are distributed geographically |
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| speciation that occurs without physical isolation |
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Definition
| mutation reduces gene flow between mutant and normal. it does so because mutant individuals have more than two sets of chromosomes. |
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