Unit 6: Evolution

Question 1

Adaptation

Answer 1

inherited characteristic that increases an organism’s chance of survival

Question 2

Bottleneck Effect

Answer 2

a change in gene frequency following a dramatic reduction in the size of an original population resulting in a loss of genetic diversity

Question 3

Analogous Structures

Answer 3

body parts in unrelated species that have common functions, but different anatomical structures; are the result of convergent evolution

Question 4

Directional Selection

Answer 4

a change in gene frequency following a dramatic reduction in the size of an original population resulting in a loss of genetic diversity

Question 5

Disruptive Selection

Answer 5

form of natural selection that favors individuals at both extremes of the phenotypic range

Question 6

Evolution

Answer 6

the change in species/populations over time

Question 7

Fossil

Answer 7

any evidence of past life; provide evidence of evolution

Question 8

Founder Effect

Answer 8

loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population

Question 9

Gene Flow

Answer 9

exchange of genes between populations due to the migration of individuals; can be a very important source of genetic variation

Question 10

Geographical Isolation

Answer 10

a mechanism of evolution in which members of a species become physically separated from each other and over time become different species

Question 11

Gene Pool

Answer 11

all of the genes present in a single species

Question 12

Genetic Drift

Answer 12

evolution that occurs due to random change or chance events in small populations

Question 13

Mutations

Answer 13

a mistake or change in the normal sequence of DNA; can be random/spontaneous OR caused by radiation, tobacco smoke, and chemical exposure

Question 13

Homologous Structures

Answer 13

anatomical structures in different species that are similar in structure, but have completely different functions; suggest evolution from a common ancestor

Question 14

Natural Selection

Answer 14

mechanism by which evolution occurs; when the environment favors a trait an organism with that trait is more likely to survive; AKA “survival of the fittest”

Question 15

Pesticide Resistance

Answer 15

the decreased susceptibility of insects over time to chemicals used to kill them

Question 16

Phylogenetic Tree/Cladogram

Answer 16

a branching diagram that shows the evolutionary relationships among organisms based on their DNA; shows common ancestry

Question 17

Primitive

Answer 17

relating to, denoting, or preserving the character of an early stage in the evolutionary or historical development of something.

Question 18

Speciation

Answer 18

the formation of a new species from an existing species

Question 19

Stabilizing Selection

Answer 19

natural selection that favors intermediate forms by acting against extreme phenotypes

Question 20

Vestigial Structure/Organ

Answer 20

A structure/organ that has little or no purpose in a modern day organism, but may have had a purpose in a distant ancestor; examples include: wings of flightless birds, human appendix & coccyx, and hip bones of whales.

Question 20

The Endosymbiotic Theory

Answer 20

explains how eukaryotic cells evolved from prokaryotic cells