Biology

6. _______ structure, features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature
8. the complete disappearance of a species from Earth
10. natural _____, The idea that Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success.
12. _______ isolation, when two populations are separated by geographic barriers such as rivers, mountains, or bodies of water
14. ______ structure, Structures that have no apparent function and appear to be residual parts from a past ancestor
16. a unit of heredity which is transferred from a parent to offspring and is held to determine some characteristic of the offspring.
17. _____ isolation, a physical incompatibility between reproductive organs of two organisms.
18. the capacity of an organism to pass on its DNA to its progeny
20. the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth.

1. an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA.
2. ______ structure, similar physical features in organisms that share a common ancestor, but the features serve completely different functions
3. _____ isolation, The separation of groups of organisms as a result of changes in their ecology or in the environment in which they live.
4. _______ isolation, occurs when mismatches in mating traits prevent mating between two species/populations.
5. The modification of an organism or its parts that makes it more fit for existence under the conditions of its environment
7. _____ isolation, occurs when two populations differ in their periods of activity or reproductive cycles
9. _____ drift, a variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.
11. the preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud, under ancient seas, lakes and rivers.
13. genetic _______, the process in which two or more populations of an ancestral species accumulate independent genetic changes through time
15. the formation of new and distinct species in the course of evolution.
19. the continued existence of organisms which are best adapted to their environment, with the extinction of others, as a concept in the Darwinian theory of evolution.