Speciation

Question 1

Ernst Mayr and George Simpson

Answer 1

didn’t believe Darwin had a good explanation for species, so used population genetics to explore speciation

Question 2

Biological Species Concept

Answer 2

a group of populations whose members have the potential to interbreed in nature and produce fertile offspring

Question 3

Hybrid examples

Answer 3

Grolar - Grizzly and Polar bear
Mule - Horse and donkey

Question 4

Mayr and Simpson Modern Synthesis

Answer 4

combined Mendilian genetics and natural selection
- Gene pool concept : idea that genes are being traded every generation with either connected or seperate populations

Question 5

Allopatric speciation

Answer 5

geographical separation of populations

Question 6

Sympatric speciation

Answer 6

non-geographic separation of populations, ecological, genetic, timing

Question 7

Geographic isolation

Answer 7

physical barrier limiting gene flow and overtime the populations will diverge into 2 new species due to natural selection and environment conditions

Question 8

Parapatric

Answer 8

habitat gradient with hybrid zone (clines)

Question 9

Vicariance

Answer 9

barrier forms through a population and seperates

Question 10

Dispersal

Answer 10

some individuals cross a barrier and form a new population

Question 11

Pre-zygotic barriers

Answer 11

preventing hybrid formation
- habitat, temporal, behavioural, mechanical isolation

Question 12

Post-zygotic barriers

Answer 12

Prevent success of hybrids
- hybrid sterility, inviability, breakdown

Question 13

Why are hybrids bad?

Answer 13

• energy costly, too much energy investment if they don’t survive or breed
• natural selection doesn’t favour a mix of 2 species

Question 14

Human race speciation arguement

Answer 14

• humans are 99.9% similar genetics
• phenotypic difference is not due to geographic barriers
• gradual differences and distance gets greater, cline