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Modern Biology Chapter 15

STUDY
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absolute age
the actual age in years of a fossil
acquired trait
a trait not determined by genes but arising as a result of experience or behavior
adapt
in populations, to change genetically over generations to become more suited to the environment
adaptation
an inherited trait that increases an organism's chance of survival in a particular environment
adaptive advantage
a favorable trait in an organism
adaptive radiation
an evolutionary pattern in which many species evolve from a single ancestral species
analogous structure
in evolution, structures in more than one organism that have similar appearance and function but different embryological origins
artificial selection
breeding of organisms by humans for specific phenotypic characteristics
biogeography
study of the geographical distribution of fossils and living organisms
cast
a type of fossil formed when sediments fill in the cavity left by a decomposing organism
coevolution
the mutual evolution of two different species interacting with each other
conserve
the act of preserving genes that remain unchanged in DNA
convergent evolution
the process by which unrelated species become more similar as they adapt to the same kind of environment
divergent evolution
the process of two or more related species becoming more and more dissimilar
extinction
the dying out of a species
fitness
a measurement of the ability of a species to respond to the pressures of natural selection; the ability of individuals to survive to propagate their genes
fossil
the remains or traces of a once-living organism
homologous
features similar features that originated in a shared ancestor
law of superposition
a law that states that successive layers of rock or soil were deposited on top of one another and the lowest level is oldest
mass extinction
one of the brief periods of time during which large numbers of species disappeared
mold
a type of fossil formed from an impression of the shape or tracks of an organism; in fungi, a mass of tangled filaments of cells, such as the fungus that grows on bread
natural selection
the process by which organisms with favorable variations reproduce at higher rates than those without such variations
population
all the members of a species that live in the same area and make up a breeding group
relative age
the comparative ages of fossils found within a single stratum
sediment
dust, sand, or mud deposited over time by wind or water
stratum
in geology, a layer of soil or rock in a cross section of the Earth
uniformitarianism
a principle that states that the geological structure of Earth resulted from cycles of observable processes and that these processes operate continuously
vestigial
referring to a functionless structure that was functional in an ancestral species