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a group of organisms that share similar characteristics and can reproduce among themselves to produce fertile offspring


change in species

natural selection

survival of the fittest


Any difference between individuals of the same species.


a varation that makes an organism better suited to its enviroment


model describing evolution as a slow process by which one species changes into a new species

punctuated equilibrium

model describing the rapid evolution that occurs when mutation of a few genes results in a species in a short period of time

sedimentary rock

a type of rock, such as limestone, that is most likely to contain fossils and is formed when layers of sand, silt, clay, or mud are cemented and compacted together or when minerals are deposited from a solution

radioactive element

element that gives off a steady amount of radiation as it slowly changes to a nonradioactive element


The study of embryos and thier development


body parts that are similar in structure and origin and can be similar in function

vestigial structure

structure, such as the human appendix, that doesn't seem to have a function and may once have functioned in the body of an ancestor


group of mammals including humans, monkeys, and apes that share characteristics such as opposable thumbs, binocular vision, and flexible shoulders


humanlike primate that appeared about 4 million to 6 million years ago, ate both plants and meat, and walked upright on two legs

homo sapiens

early humans that likely evolved from Cro-Magnons

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