evolution of species

Question 1

a species is

Answer 1

a group of organisms that can interbreed to produce fertile offspring

Question 2

mutations are

Answer 2

random, spontaneous changes in genetic material and the only source of new alleles

Question 3

rates of mutation can be increased by environmental factors such as

Answer 3

certain types of radiation and some chemicals

Question 4

mutations that have little effect on the organism are

Answer 4

neutral

Question 5

mutations that give the organism a disadvantage and decrease its survival chances are

Answer 5

harmful

Question 6

mutations that give the organism an advantage and increase its chances of survival are

Answer 6

beneficial

Question 7

new alleles produced by mutation can result in

Answer 7

plants and animals becoming better adapted to their environments

Question 8

variation within a population of living organisms makes it possible for

Answer 8

a population to evolve over time in response to changing environmental conditions

Question 9

species often produce

Answer 9

more offspring than the environment can support

Question 10

the intensity of a selective factor such as predation is called

Answer 10

selection pressure

Question 11

natural selection/survival of the fittest occurs when

Answer 11

there are selection pressures

Question 12

an adaption is

Answer 12

an inherited feature of an organism that makes it well suited to survive in its habitat

Question 13

the best-adapted individuals in a population have a

Answer 13

selective advantage

Question 14

individuals with a selective advantage…

Answer 14

survive to reproduce, passing on the favourable alleles that confer the selective advantage to their offspring

Question 15

the favourable alleles

Answer 15

increase in frequency within the population

Question 16

speciation is

Answer 16

the evolution of 2 or more species from 1 original ancestor species

Question 17

speciation occurs after

Answer 17

part of a population becomes isolated by an isolation barrier

Question 18

isolation barriers can be

Answer 18

geographical, ecological or behavioural

Question 19

different mutations occur in

Answer 19

each sub-population after speciation

Question 20

natural selection selects for

Answer 20

different mutations in each sub-population due to different selection pressures

Question 21

each sub-population evolves until…

Answer 21

they become so genetically different that they are 2 different species and can no longer interbreed to produce fertile offspring

Question 22

an isolation barrier is

Answer 22

a barrier that prevents interbreeding and gene exchange between sub-populations of a species

Question 23

natural selection is

Answer 23

the process which ensures the best adapted individuals survive