EVO

Question 1

What is a gene pool?

Answer 1

A gene pool comprises all the genetic information in an interbreeding population.

Question 2

What are the four sources of genetic variation

Answer 2

mutation
random fertilization
independent assortment (miosis)
crossing over (miosis)

Question 3

describe how natural selection leads to speciation

Answer 3

The population is separated due to a barrier (e.g. geographical). That means no gene flow between populations. The populations experience different selection pressures. Increase the frequency in favourable alleles. This leads to specialization because the populations are unable to interbreed to produce fertile offspring

Question 4

What is allopatric speciation

Answer 4

Geographical barrier separates a population and stops the gene flow, leading to speciation.

Question 5

What is sympatric speciation

Answer 5

Sympatric speciation occurs when there is no geographical isolation but gene flow is still prevented leading to reproductive isolation.

Question 6

How do you define a species

Answer 6

The members of the species can interbreed to produce fertile offspring.

Question 7

What are the three methods of defining a species.

Answer 7

· morphological similarity
· biochemical similarity
· sharing a common gene pool.

Question 8

What is morphological similarity?

Answer 8

Comparing physical structures or homologous features.

Question 9

What is DNA hybridization

Answer 9

• DNA of different species are extracted and heated (together), breaking
• The mixture is combined to allow DNA to recombine with that of the other species
• The hybrid DNA is reheated. The higher the melting point, the closer the relation of the species

Question 10

How is DNA sequencing used to determine if individuals are from the same species

Answer 10

The closer the sequence of bases (A, T, C, G), the closer related the species

Question 11

What is divergent evolution

Answer 11

Where species come from a common a ancestor but evolved to become different

Question 12

What is convergent evolution

Answer 12

Where species developed similar features due to facing similar selection pressures without having a common ancestor.

Question 13

What is adaptive radiation

Answer 13

Organisms diversify rapidly from ancestral species into new forms due to selection pressures. (bird example)

Question 14

Describe temporal isolation as a pre-zygotic factor of reproductive isolation

Answer 14

The breeding cycle doesn’t overlap due to factors such as time

Question 15

Describe behavioral isolation as a pre-zygotic factor of reproductive isolation.

Answer 15

Differences in mating calls or rituals/ not attracted to each other. Their behavior is not compatible.

Question 16

Describe mechanical isolation as a pre-zygotic factor of reproductive isolation

Answer 16

incompatible sexual organs (duck genitals)

Question 17

Describe gamete isolation as a pre-zygotic factor of reproductive isolation

Answer 17

sperm and egg can not fuse

Question 18

Describe hybrid inviability as a post-zygotic factor of reproductive isolation.

Answer 18

The zygote will not survive till reproductive age.

Question 19

Describe hybrid sterility as a post-zygotic factor of reproductive isolation.

Answer 19

The offspring is infertile.

Question 20

Describe primary succession

Answer 20

When a new environment is colonised

Question 21

Describe secondary succession

Answer 21

When an environment is recolonized e.g. after a fire or flood