Chapter 15.3

Question 0

struggle for existence

Answer 0

when members of each species compete regularly to obtain food, living space, and other necessities of life

Question 1

artificial selection

Answer 1

when humans select better animals for breeding

nature creates the variation, and humans select the useful variations

Question 2

fitness

Answer 2

the ability of an individual to survive and reproduce in its specific environment

Question 3

adaptation

Answer 3

any inherited characteristic that increases an organism’s chance of survival

Question 4

survival of the fittest

Answer 4

individuals who are better suited to the environment, or have adaptations enabling fitness, survive and reproduce more successfully than others

Question 5

natural selection

Answer 5

survival of the fittest, except that the traits selected contributed to an organisms’ fitness

Question 6

descent with modification

Answer 6

each species descends with changes from other species over time

Question 7

common descent

Answer 7

the common ancestor of all living things

Question 8

homologous structures

Answer 8

structures that have different mature forms but develop from the same embryonic tissue

Question 9

vestigial organs

Answer 9

small homologous organs resembling miniature tails, legs, or other structures