population differentiation and speciation - lecture 17

Question 1

Biological evolution

Answer 1

Gentic changes in a group of organisms

Question 2

Anagenesis

Answer 2

Evolution taking place in a single group )a lineage) with the passage of time

Question 3

Cladogenesis

Answer 3

splitting of one lineage into two; new species arise

Question 4

Sympatric speciation ( a form of cladogenesis)

Answer 4

No physical barrier,divergence over time

Question 5

Allopatric speciation ( a from of cladenogenesis)

Answer 5

population diveded by a physical barrier

Question 6

What is the phentic species concept?

Answer 6

Individuals/ populations cluster together, use this pattern to assign species boundaries

Question 7

What is the biological species concept?

Answer 7

Use to pattern of gene flow to assign specied boundaries

Question 8

what is the phylogentic species concept?

Answer 8

Species are on the tips on a phylogene y- they represent the smallest set of organims that share a comon ancestor and can be distinguished from other such sets

Question 9

What is phylogeny?

Answer 9

A representation of the relatinship between groups of organisms
- typically constructed using charcters

Question 10

What is a rooted treee?

Answer 10

Use a distantly related species to infer the ancestral state

Question 11

what is an unrooted tree?

Answer 11

Without an outgroup , relatioship between lineages known byt not an ancestral relationship

Question 12

Allopatric speciaion

Answer 12

speciation caused by geographic isolation

Question 13

Peripatric speciation

Answer 13

describes speciation when a population is peripheral to a main population

Question 14

parapatric speciation

Answer 14

speciation when populations are not isolated , but adjoinig , individuals mate locally

Question 15

sympatric speciation

Answer 15

described speciation when populations overlap

Question 16

An example of peripatric speciation

Answer 16

• new small population founded

- small population size(genetic drift) and selection in a new niche leads to a new species

Question 17

Exampleof parapatric speciation

Answer 17

• continuous population without a barrier
• some contact zone with hybridization
• limited gene flow across contact zone
• usually assumes an environemntal gradient

Question 18

secondary contact

Answer 18

lineages may split through various processes t hrough time, but then migration or lossof barriers brings them back together