Lec. 39 Origins of Species

Question 1

What are the 5 Prezygotic Isolating Mechanisms

Answer 1

1. Ecological isolation
2. Behavioral isolation
3. Temporal isolation
4. Mechanical isolation
5. Gametic isolation

Question 2

What is prezygotic isolation

Answer 2

before fertilization

Question 3

what is postzygotic isolation

Answer 3

after fertilzation

Question 4

What is ecological isolation

Answer 4

when organisms live in different environments

Question 5

what is behavioral isolation

Answer 5

when organisms practice different mating rituals

Question 6

what is temporal isolation

Answer 6

when organisms mate/reproduce at different times

Question 7

what is mechanical isolation

Answer 7

organisms physically cannot mate

Question 8

Gametic isolation

Answer 8

reproductive barrier that prevents the fertilization of the egg

Question 9

what are the types of postzygotic isolation mechanisms

Answer 9

the hybrids are…
1. inviable (can’t develop properly)
2. infertile (cannot reproduce)
3. have a lower fitness

Question 10

what keeps 2 species reproductively isolated?

Answer 10

prezygotic isolation and postzygotic isolation

Question 11

How do species form?

Answer 11

speciation

Question 12

what causes speciation?

Answer 12

1. population divergence
2. reproductive isolation evolves

Question 13

what is allopatric speciation?

Answer 13

geographic separation of populations cause “accidental” reproductive isolation

Question 14

what is allopatric vicariance

Answer 14

a barrier that arises within an existing population

Question 15

what is allopatric dispersal

Answer 15

when individuals cross an existing barrier

Question 16

what is sympatric speciation

Answer 16

speciation without geographic isolation through gene flow

Question 17

what is sympatric polyploidy

Answer 17

when an organism develops an extra set of chromosomes

Question 18

what is allopolyploidy

Answer 18

hybridization between species with different chromosomes

Question 19

what is autopolyploidy

Answer 19

an error in meiosis causing a zygote to have an extra set of chromosomes

Question 20

what is sympatric nonrandom mating

Answer 20

assortative mating (like organisms mate with other like organisms) and disruptive sexual selection

Question 21

what is sympatric habitat differentiation

Answer 21

different uses of the local habitat or non-overlapping cruising range

Question 22

what are the modes of speciation

Answer 22

allopatric speciation and sympatric speciation

Question 23

what are the mechanisms of allopatric speciation (geographic isolation)

Answer 23

vicariance or dispersal

Question 24

what are the mechanisms of sympatric speciation (reproductive isolation)

Answer 24

polyploidy, habitat differentiation, nonrandom mating