Speciation

Question 1

What is a species?

3

Answer 1

Evolutionary independent pop

• thought to genetically separate from each other so evolutionary mechs that affect on one effect another
• linage splitting event that produce 2 or more separate species

Question 2

Biological species concept ( BSC)

3

Answer 2

• def : member pop can (potentially ) interbreed and produced fertile offspring
• evidence: (in)ability to reproduce
• need barrier to reproduction

Question 3

What are the 2 BSC reproductive barriers ?

2 with 2 sub points

Answer 3

A) pre zygotic isolation

• 5 common
• prevent successfully mating/ sperm from fertilizing egg

B) post zygotic isolation

• 2 common
• offspring can survive / reproduce

Question 4

5 common pre zygotic barriers

Answer 4

• diff in mating timing
• habitat/ ecological isolation (rarely encounter )
• behavioral (diff mating rituals )
• mechanical ( incompatible reproductive structures)
• genetic barrier (incompatible egg/sperm)

Question 5

Subspecies?

2

Answer 5

Live discrete geographic area/ have distinguishing features

- but not distinct enough the own species

Question 6

2 common post zygotic barriers ?

Answer 6

A) hybrid invisibility (embryos don’t develop/ babies can’t reach sexual maturity/ fail to mate)

B) hybrid sterility or less fertile

Question 7

What are the disadvantages of BSC?

3

Answer 7

• if the pops don’t overlap it’s har tell if can reproduce
• fossils
• asexual

Question 8

Morphospecies concept

3

Answer 8

• def: same/similar anatomy
• evidence: morphological diff
• benefits: wildly applicable, sexual,asexual , fossils

Question 9

What are the drawbacks of morphospecies?

2

Answer 9

• diff species can look similar

- same species look diff at diff points in life

Question 10

Ecological species concept

3

Answer 10

• def: same ecological niche
• evidence: ecology
• benefits : asexual

Question 11

What are two drawbacks of ecological species concept?

Answer 11

• some species change niche over lifecycle

- diff species share same niche

Question 12

Phylogenetic species concept (PSA)

3

Answer 12

• def: smallest , non- divisible monophyletic group
• evidence: tree
• advantages: any pop

Question 13

Drawbacks of PSA?

Answer 13

• carefully construct trees only available for some species

- hard to make new trees

Question 14

What are the 3 steps to speciation?

Answer 14

1) pop must be isolated
- little / no gene flow

2) pop must genetically diverge
3) pre/post zygotic barrier form

Question 15

What are the 2 types of speciation?

Answer 15

• allotropic ( geographic isolation)

- sypatric (reproductive isolation)

Question 16

What is allopathic isolation?

2

Answer 16

• geographically isolated (ranges don’t overlap)

- isolation can start by dispersal or vicariance

Question 17

Dispersal

Answer 17

Movement individuals away original state (one way move , no gene flow)

Question 18

Vicariance

Answer 18

New physical barriers that dived the pop

Question 19

Allopathic isolation - from dispersal

3 with sub points

Answer 19

1) some individuals go new location ( founder effect )
- stop reduce gene flow

2) allele f if new diff then old one
- genetic drift (if small pop)
- natural selection ( if diff habitat )
- mutations (with another mech)

3) reproductive barriers arise
- speciation complete

Question 20

Allopathic isolation - from vicariance

3

Answer 20

1) stop gene flow
2) pop allele f start diverge

3) reproductive barriers
- speciation complete

Question 21

What is sypatric speciation?

Answer 21

Reproductive isolation within pop

Question 22

Disruptive selection?

Answer 22

Within pop/diff pop may become isolated due diff food/habitat preference