origin of species

Question 1

what is the difference between microevolution and macroevolution?

Answer 1

microevolution has evolutionary changes in allele frequency within the population, whereas macroevolution has evolution occur at or above species level

Question 2

what is the biological species concept?

Answer 2

a group of interbreeding individuals that are reproductively isolated from other groups

Question 3

what is reproductive incompatibility? what does that make the species have?

Answer 3

can only reproduce with members of their own species. this makes species have a closed gene pool with no mixing

Question 4

there are four problems to the biological species concept. what are they?

Answer 4

1. applies just to sexually reproducing species
2. suggests two different species would never mate
3. ecological species concept (group species together based on how similarly they adapt to their environment)
4. phylogenetic species concept (evolutionary history through DNA sequencing)

Question 5

reproductive isolation in the biological species concept occurs through what two types of isolation mechanisms?

Answer 5

prezygotic and postzygotic

Question 6

what are some examples of prezygotic isolation mechanisms? (5)

Answer 6

1. ecological (habitat) selection
2. temporal isolation (when)
3. behavioral isolation
4. mechanical isolation (lock and key)
5. gamete isolation (chemical incompatibility)

Question 7

what happens in postzygotic isolation? (3)

Answer 7

1. sometimes the zygote dies very early on
2. sometimes the zygote survives and forms an F1 hybrid where offspring cannot reproduce
3. F2 hybrid where offspring is infertile and has a lower fitness

Question 8

how does speciation occur when reproductive isolation arises between populations?

Answer 8

allopatric and sympatric speciation

Question 9

what is the difference between allopatric and sympatric speciation?

Answer 9

allopatric speciation is when a single population becomes reproductively isolated by a geographic barrier. sympatric speciation occurs without a barrier, where subgroups begin forming

Question 10

four steps to how a species can become reproductively isolated and make a speciation event occur

Answer 10

1. a single population becomes sub-divided
2. they become more likely to mate with individuals in their group, reducing gene flow through pre/postzygotic mechanisms
3. microevolution independently works on subgroups
4. separated populations evolve and adapt

Question 11

what are some examples of microevolution? (4)

Answer 11

natural selection, genetic drift, mutation, artificial selection