CH 224

Question 1

microevolution

Answer 1

Changes in allele freqs within pops

Question 2

Macroevolution

Answer 2

changes at species level or above

Question 3

All species have a common unicellular offspring; true or false

Answer 3

true

Question 4

What % of species that ever existed are still around?

Answer 4

0.1%

Question 5

Speciation

Answer 5

Existing species -> new species

Question 6

Bio species concept

Answer 6

Pops who can interbreed and produce viable fertile offspring are species

Question 7

Prezygotic barriers

Answer 7

-impede diff species from mating
-preventing successful completion of mating
-hindering fertilization if mating is successful

Question 8

Habitat isolation

Answer 8

Rare encounters and diff habitats despite no physical barriers

Question 9

Temporal isolation

Answer 9

Different reproductive periods or seasons

Question 10

Behavioral isolation

Answer 10

Unique mating & courtship rituals

Question 11

Mechanical isolation

Answer 11

Structural differences make mating physically impossible

Question 12

Gametic isolation

Answer 12

Incompatible gametes

Question 13

Postzygotic barriers

Answer 13

If mating occurs, hybrid zygote is prevented from developing into viable, fertile adult

Question 14

Hybrid

Answer 14

Offspring of crosses between different species

Question 15

Reduced hybrid viability

Answer 15

Genes interact to impair embryonic dev: if survival, no normal dev, often sterile

Question 16

Hybrid breakdown

Answer 16

Where F1 is fertile, but F2 is not

Question 18

Limits of bio species concept

Answer 18

No app for
-fossils
-asexual organisms
-all prokaryotes
-hybrids exist

Question 19

Morphological species concept

Answer 19

-Defines spp. by structural features
-fossils, sexual & asexual spp.
-subjective

Question 20

Ecological species concept

Answer 20

-defines spp by eco niches
-sexual and asexual
-emphasizes disruptive selection

Question 21

Phylogenetic species concept

Answer 21

-spp. as smallest group on phylogenetic tree
-sexual and asexual spp.
- diff to determine degree of diff for sep spp.

Question 22

Steps of speciation

Answer 22

1. Identical pops diverge
2. Rep isolation maintains diffs.

Question 23

Allopathic speciation

Answer 23

Sub pops geo isolated: barrier depends on mobility of pop
-not a bio mech on its own

Question 24

Sympatric speciation

Answer 24

One pop splits into two, still geo overlap
- from sexual selection and/or habitat preference

Question 25

Polyploidy

Answer 25

Extra sets of chromosomes from cell division mistakes -common in plants

Question 26

Habitat differentiation

Answer 26

New niches cause sympatric speciation eg: new food supply

Question 27

Sexual selection

Answer 27

Non random mating an lead to speciation

Question 28

Hybrid zones

Answer 28

Region where diff species mate and potentially produce hybrids

Question 29

Hybrid zone outcome: reinforcement

Answer 29

Strengthens reproductive barriers: hybrids are less fit, decreasing hybridization over time

Question 30

Hybrid zone outcome: fusion

Answer 30

Barriers are weak, gene flow increase between pops and they can fuse into one

Question 31

Hybrid zone outcome: stability

Answer 31

Cont. formation of hybrids: gene flow from outside can overwhelm reproductive barriers, keeping them from strengthening

Question 32

Hybrid zone

Question 33

Timeframe of speciation

Answer 33

Can be fast or slow

Question 34

Macroevolution cont.

Answer 34

Cumulative effect of many speciation and extinction events