Biology Vocab Ch. 15 And 16

Front 1

evolution

Back 1

change in a kind of organism over time; process by which modern organisms have descended from ancient organisms

Front 2

theory

Back 2

well-tested explanation that unifies a broad range of observations

Front 3

fossil

Back 3

preserved remains or evidence of an ancient organism

Front 4

adaptation

Back 4

inherited characteristic that increases an organism's chance of survival

Front 5

natural selection

Back 5

process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest

Front 6

homologous structures

Back 6

structures that have different mature forms in different organisms but develop from the same embryonic tissues

Front 7

vestigial organ

Back 7

organ that serves no useful function in an organism

Front 8

survival of the fittest

Back 8

process by which individuals that are better suited to their environment survive and reproduce most successfully; also called natural selection

Front 9

directional selection

Back 9

form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

Front 10

stabilizing selection

Back 10

form of natural selection by which the center of the curve remains in its current position; occurs when individuals near the center of a distribution curve have higher fitness than individuals at either end

Front 11

disruptive selection

Back 11

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

Front 12

radioactive dating

Back 12

technique in which scientists calculate the age of a sample based on the amount of remaining radioactive isotopes it contains

Front 13

half-life

Back 13

length of time required for half of the radioactive atoms in a sample to decay

Front 14

adaptive radiation

Back 14

process by which a single species or small group of species evolves into several different forms that live in different ways; rapid growth in the diversity of a group of organisms

Front 15

convergent evolution

Back 15

process by which unrelated organisms independently evolve similarities when adapting to similar environments

Front 16

punctuated equilibrium

Back 16

pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change