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change in a kind of organism over time; process by which modern organisms have descended from ancient organisms
descent with modification
process by which descendants of ancestral organisms spread into various habitats and accumulate adaptations to diverse ways of life
process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest
information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived
remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species.
selective breeding of domesticated plants and animals to produce offspring with desired genetic traits
evolution on the smallest scale—a generation-to-generation change in the frequencies of alleles within a population
condition that occurs when the frequency of alleles in a particular gene pool remain constant over time
biological species concept
definition of a species as a population or group of populations whose members can breed with one another in nature and produce fertile offspring
condition in which a reproductive barrier keeps two species from interbreeding
separation of populations as a result of geographic change or migration to geographically isolated places
pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change
study of multicellular organisms as they develop from fertilized eggs to fully formed organisms
the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products
evidence of change
2. vestigial structures
3. embryos have similar stages of development
4. molecular biology
1. natural selection screens traits available
2. natural selection favors traits that fit current environment
the bottle neck effect
When a population is srunk by external factors causing sudden species change.
when a few individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool isn't reflective of the source population
reproductive barriers between species
1. timing (different breeding seasons)
4. reproductive structures are incompatible
5. offspring can be infertile
geographic isolation and speciation
1. populations are separated
2. changes in the gene pool occur
3. genetic differences evolve
4. the two populations can no longer interbreed
a model of evolution in which gradual change over a long period of time leads to biological diversity
refinement of existing adaptations
complex structures can evolve from simpler structures having the same basic function
Ex: complex eye
adaptations of existing structures to new functions
example: penguin wings have been modified for swimming
method of determining the age of a fossil by comparing its placement with that of fossils in other layers of rock
when two or more species sharing a common ancestor become more different over time
the process by which unrelated species become more similar as they adapt to the same kind of environment
structures that do not have a common evolutionary origin but are similar in function
three domain system
A system of taxonomic classification based on three basic groups: Bacteria, Archaea, and Eukarya
the "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance
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