Lecture 21: Speciation

Question 1

speciation

Answer 1

process by which one species splits into 2

Question 2

morphological species concept

Answer 2

based on the physical structures of an organism; size, presence or absence of specific body parts

Question 3

biological species concept

Answer 3

based on interbreeding and producing viable offspring in nature

Question 4

interbreeding

Answer 4

breeding with members of another group

Question 5

ecological species concept

Answer 5

how species interact with living and nonliving parts of the environment; based on ecological niche

Question 6

Isolating mechanisms

Answer 6

pre-zygotic and prevent fertilization

Question 7

what are the 5 isolation mechanisms?

Answer 7

1. habitat isolation 2. temporal isolation 3. behavioral isolation 4. mechanical isolation 5. gametic isolation

Question 8

habitat isolation

Answer 8

2 species live in a completely different place in their environment and never cross paths; no opportunities to mate

Question 9

temporal isolation

Answer 9

not reproducing at the same time; day, month, year, etc

Question 10

behavioral isolation

Answer 10

mating rituals; ex: courtship-birds; species specific

Question 11

mechanical isolation

Answer 11

mating is attempted, but the two different species are morphologically incompatible

Question 12

gametic isolation

Answer 12

mate successfully, but the gametes are not biochemically compatible with each other; receptors or egg and sperm don’t match

Question 13

Post zygotic isolation

Answer 13

permit fertilization; zygotes form but the hybrids are not presistant

Question 14

what are the two kinds of post zygotic isolation?

Answer 14

reduced hybrid viability and hybrid breakdown

Question 15

reduced hybrid viability

Answer 15

hybrid embryo will not develop or will develop but will be sickly; ex: mule

Question 16

hybrid breakdown

Answer 16

1st generation hybrids viable and fertile, but hybrids interbreed with each other–>loss of fitness

Question 17

Which isolation mechanisms prevent mating?

Answer 17

Habitat, Temporal, and Behavioral

Question 18

Which isolation mechanisms prevent fertilization, but mating occurs

Answer 18

Mechanical and Gametic

Question 19

Which isolation mechanisms help fertilization, but the hybrids cannot persist?

Answer 19

Reduced Hybrid and Hybrid Breakdown

Question 20

Allopatric speciation

Answer 20

physical geographic barrier between the 2 populations that prevents them from interbreeding–>causes them to separate over time

Question 21

sympatric speciation

Answer 21

reproductive isolation without geographic isolation or a physical barrier

Question 22

what are the mechanisms of sympatric speciation?

Answer 22

1. polyploidy 2. sexual selection 3. niche differentiation

Question 23

polyploidy

Answer 23

hybrids that have more than 2 sets of chromsomes

Question 24

sexual selection

Answer 24

selection for different traits in males and females; ends up reproducing in their subgroups which leads to disruptive selection

Question 25

niche differentiation

Answer 25

subpopulations use habitat or resources not used by the rest of the population; diverge from each other; disruptive selection