CH.5-Speciation/Macroevolution

Question 1

What’s microevolution?

Answer 1

Changes in allele/genotype frequencies over generations

Question 2

What’s macroevolution?

Answer 2

Broad patterns of evolution over long time spans (1000 yrs)

Question 3

What is speciation?

Answer 3

Origin of new species (Stepping stone between micro and macro)

Question 4

What is a species according to Ernst Mayr?

Answer 4

Population/Group of populations whose individuals can interbreed and produce viable, fertile offspring (Not w/ other species)

Question 5

What keeps species together when populations are spread out?

Answer 5

1) Gene flow (active between pops of same species)
2) Reproductive isolation (from dif species)

Question 6

How does gene flow help keep species tgt when populations are spread out?

Answer 6

When individuals from 1 population of species move ==> produce more offspring that help maintain species’ gene pool
Gene pool tends to change due to dif env but gene flow causes gene pool to remain more cte

Question 7

How does reproductive isolation keep species tgt when populations are spread out?

Answer 7

Prevents mating with other species or production of viable/fertile offspring ==> Prevents mixing w other species’ gene pool

Question 8

Choose the right answer:
Reproductive isolation that arises between populations of the (same/different) species may lead to the formation of (old/new) species.

Answer 8

same - new

Question 9

Reproductive isolation is due to barriers preventing mating: What are they?

Answer 9

1) Prezygotic barriers (prior to fertilization)
2) Postzygotic barriers (after fertilization)

Question 10

What are the types of prezygotic barriers?

Answer 10

1) HABITANT ISOLATION
(EX: Garter snakes live in same geographic area but one lives in water and other on land)
2) TEMPORAL ISOLATION
(EX: Skunks in same geo area but mate in different seasons)
3) BEHAVIOURAL ISOLATION
(EX: Mating calls in frogs unique to ch/ species, unique sequence of lights of fireflies)
4) MECHANICAL ISOLATION
(EX: Genital opening of dif snails are opposite sides)
5) GAMETIC ISOLATION
(EX: Release gametes into water, other species cannot fertilize other species’ eggs)

Question 11

What are types of postzygotic barriers?

Answer 11

1) REDUCED HYBRID VIABILITY
(EX: Able to have hybrid of 2 species, but frail and can’t reproduce)
2) REDUCED HYBRID FERTILITY
(EX: Mules (donkey+horse) are infertile)
3) HYBRID BREAKDOWN
(EX: First gen is viable but later gens become more sterile)

Question 12

Species concept cannot be applied to what?

Answer 12

1) Fossils (Can’t tell which groups mate successfully)
2) Asexually reproducing organisms

Question 13

What are the other definitions of species?

Answer 13

1) Morphological species concept
2) Ecological species concept
3) Phylogenetic species concept

Question 14

Morphological species concept:
1. Species defined by ——
2. Can be used for ——- and ——-
3. —— criteria

Answer 14

• physical features
• all living organisms and fossil remains
• subjective

Question 15

Ecological species concept:
1. Defined by its ——. How it —– with other living organisms and the ———-
2. Can be applied to —– but not —-

Answer 15

• ecological niche — interacts —– physical environment
• all living organism —- fossil remains

Question 16

Phylogenetic species concept:
1. Species defined by —— in —– and physical ——
2. Can be applied to —–, DNA not usually available for —–

Answer 16

• similarity in DNA — morphology
• all living organisms — fossil remains

Question 17

How do new species arise?

Answer 17

Gene flow must stop between populations of existing species ==> Separated pops must be exposed to dif pressures

Question 18

What are the modes of speciation?

Answer 18

1) Allopatric speciation
2) Sympatric speciation

Question 19

What does allopatric mean?

Answer 19

Different country

Question 20

What’s allopatric speciation?

Answer 20

Reproductive isolation due to physical environmental barrier ==> New species due to physical barrier separating pops of existing species

Question 21

What’s sympatric speciation?

Answer 21

Reproductive isolation between individuals in same area ==> New species in same geo area due to formation of reproductive barriers

Question 22

What does sympatric mean?

Answer 22

In same country

Question 23

For sympatric speciation, reproductive isolation between 2 pops in same geo area can arise due to:

Answer 23

1) Chromosomal changes
2) Habitat differentiation
3) Sexual selection

Question 24

What is chromosomal changes is sympatric speciation?

Answer 24

New species formed when viable/fertile polyploid offspring is created ==> Isolated form parent kind reproductivelyW

Question 25

What is habitat differentiation in sympatric speciation?

Answer 25

Genetic variation within a pop allows individuals to exploit a habitat/resource not used by rest of pop

Question 26

What is sexual selection?

Answer 26

Select mate by characteristic, certain features

Question 27

What is speed of speciation?

Answer 27

Species appear to remain relatively the same over long periods then new species arise

Question 28

What is Punctured Equilibrium?

Answer 28

Speciation occurs rapidly during moments when environmental pressures change

Question 29

What are the 2 types of patterns that can happen in time course of speciation?

Answer 29

1) Punctuated pattern (drastic change)
2) Gradual pattern (gradual change)