Unit 7 Part 2 Flashcards Preview

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Flashcards in Unit 7 Part 2 Deck (20):
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Evolution

Gradual change in a species through adaptation over time

1

Natural Selection

Mechanism for change in populations; occurs when organisms with favorable variations survive, reproduce, and pass their variations to the next generation.

2

Adaptive Radiation.

Divergent evolution in which ancestral species evolve into an array of species to fit a number of diverse habitats

3

Vestigial Structure.

A structure in a present-day organism that no longer serves its natural purpose, but was probably useful to an ancestor; provides evidence of evolution.

4

Speciation

The formation of new species as a result of geographic, physiological, anatomical, or behavioral factors that prevents previously interbreeding populations from breeding with each other.

5

Punctuated Equilibrium.

A hypothesis holding that the evolution of species proceeds in a characteristic pattern of relative stability for long periods of time interspersed with much shorter periods during which many species become extinct and new species emerge.

6

Camouflage.

The act, means, or result of obscuring things to deceive an enemy, as by painting or screening objects to that they are list to view in the background

7

Homologous Structure.

Structures with common evolutionary origins; can be similar in arrangement, in function, or both.

8

Polyploid.

Any species with multiple sets of the normal set of chromosomes; results from errors during mitosis or meiosis.

9

Gradualism.

Idea that species originate through a gradual change of adaptations.

10

Genetic Equilibrium.

Condition in which the frequency of alleles in a population remains the same over generations.

11

Artificial Selection.

Process of breeding organisms with specific traits in order to produce offspring with identical traits.

12

Directional Selection.

Natural selection that favors one of the extreme variations of a trait; can lead to rapid evolution in a population.

13

Disruptive Selection.

Natural selection that favors individuals with either extreme of a trait; tends to eliminate intermediate phenotypes.

14

Stabilizing Selections.

Natural selection that favors average individuals in a population; results in a decline in population variation.

15

Convergent Evolution.

Evolution in which distantly related organisms evolve similar traits; occurs when unrelated species occupy similar environments.

16

Divergent Evolution.

Evolution in which species that once were similar to an ancestral species diverge; occurs when populations change as they adapt o different environmental conditions.

17

Genetic Isolation.

Occurs whenever a physical barrier divides a population, which results in individuals no longer being able to mate; can lead to the formation of a new species.

18

Genetic Drift.

Alteration of allelic frequencies in a population by chance events; results in a disruption of genetic equilibrium.

19

Mimicry.

Structural adaptation that enables one species to resemble another species; may provide protection from predators or other advantages.