Unit 4- Evolution & Classification Flashcards Preview

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Flashcards in Unit 4- Evolution & Classification Deck (34)
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1

directional selection

a change in the allele frequency of a population when an organism favors an extreme phenotype

2

disruptive selection

a change in the allele frequency of a population when an organism is not favored for the most common phenotype

3

stabilizing selection

favors the average individuals in a population

4

geographical isolation

occurs when a physical barrier separates a population; ex. two populations are separated by a body of water or a mountain

5

behavioral isolation

two populations have different courtship rituals;

6

temporal isolation

occurs when two or more species reproduce at different times

7

habitat isolation

two species live in the same area but live in different habitats within that area; ex. a species snake lives on land and another species of snake lives in water

8

gametic isolation

sperm and egg cannot fuse because the surface proteins have changed

9

mechanical isolation

sex organs of closely related species are incompatible (meaning they do not fit together)

10

founder effect

allele frequencies change due to a migration; when a few individuals colonize a new habitat, the small founding population makes up the new gene pool; type of genetic drift

11

evolution

a long slow process of change over time; a change in the gene pool over time

12

bottleneck effect

drastic reduction in population size and by chance some individuals survive to make up the new gene pool; ex. natural disaster, fire, flood; type of genetic drift

13

genetic drift

an accidental change in gene frequency that affects small populations only as a result of chance

14

genetic equilibrium

a state of constant allele frequency in a population throughout generations

15

vestigial structure

an anatomical organ in organisms that is no longer used or has a function; ex. appendix in humans, eyes in sightless species

16

homologous structure

an anatomical structure that is found in different species, it has similar structure/make-up but different functions; ex arms, wings, and flippers

17

analogous structure

a structure that is found in different species that has a dissimilar structure but similar function; ex a bird wing, bat wing & butterfly wing

18

gene pool

the combined genetic material of all the members of a given population

19

paleontologist

a scientist that studies fossils

20

speciation

evolution of 1 or more new species from a single ancestor

21

natural selection

Darwin's idea that individuals best adapted to the environment will survive and reproduce; nature provides variation and nature chooses which traits are best adapted

22

artificial selection

AKA selective breeding; nature provides variation and humans choose whcih traits are best adapted

23

niche

the role of an organism in the environment

24

adaptation

the long neck of a giraffe makes it better suited to survive

25

fossil

preserved remains of ancient organisms

26

Hardy-Weinburg

under specific conditions, allele frequencies will remain constant (equilibrium)

27

Darwin

came up with the theory of natural selection; wrote book: On the Origin of Species by Means of Natural Selection

28

Hutton

scientist that concluded the age of the earth was very old

29

Malthus

theorized that the population of humans was growing too rapidly that supply couldn't keep up with demand

30

Lamarck

first to say that organisms change over time