Unit 14 #2 - Speciation

Question 1

Do ring species interbreed

Answer 1

yes, but end of ring no

Question 2

Biological species

Answer 2

group of population (same time place) that can reproduce and produce viable offspring and are reproductively isolated from each other

Question 3

What is speciation

Answer 3

reproductive isolation/block gene flow bc mutation, non-random mating, selection, genetic drift

Question 4

Name 4 pre-zygotic isolating mechanism

Answer 4

1-Ecological (tigers and lions, rarely see ach other)
2-behavioural (different song birds or show off blue feet by dance, diff mating rituals)
3-Temporal (leopard frog and wood frog, diff reproductive season)
4-mechanical (cw/ccw snails)
5-gametic barrier (happens for all species that sometimes just no gamete fusion so no zygote)

Question 5

Name a pre-zygotic isolating mechanism

Answer 5

Reduced hybrid viability (grolar bear) and reduced hybrid fertility (horse/donkey)

Question 6

Reinforcement

Answer 6

if hybrids at selective disadvantage for reproduction, then sympatric species will evolve to improve pre-zygotic isolating mechanism and avoid hybrid production.

In other words, evolution is pushed into a certain direction for more reproduction.

ie peacock biger and bigger tails bc female prefer.

Question 7

Allopatric speciation

Answer 7

separated by time and place

Question 8

Sympatric speciation and how it can happen

Answer 8

sharing time and place

1- Polyploidy
2-chromosomal structural changes
3-mutation that isolates population
4-disruptive selection
5-sexual selection

Question 9

How many mass extinctions

Answer 9

5 and we are in 6th, darwin believed geological change was slowly, but no!

Question 10

What is the process that leads to a species being hybridise

Answer 10

species connected by gene flow, barrier to gene flow, populations diverge, gene flow in hybrid zone, 3 choice: reinforcement (more barriers so no hybrids), fusion (less barriers so fuse), stability (hybrid production)

Question 11

Punctuated equilibrium model

Answer 11

speciation events can occur abruptly (punctuated equilibrium ie when polyploidy or chromosomal rearrangement) compared to darwins belief that evolutionnary change is slow (gradualism)