3-speciation

Question 1

speciation

Answer 1

evolutionary process by which new species form

Question 2

species

Answer 2

group of organisms that can (or potentially can) reproduce with each other And produce fertile offspring but is reproductively isolated from other organisms

Question 3

3 STEPS TO SPECIATION

Answer 3

1. all/part of a population becomes genetically isolated from other members of the population/species
   
   1. No gene glow!!
2. Isolated populations diverge genetically
   
   1. Due to mutations, natural selection, and/or genetic drift affecting populations independently
3. Reproductive isolation
   
   1. Prezygotic/postzygotic barriers to reproductive evolve
      
      1. So….. if they isolate for long enough and they come together again…
      2. BOOM no more able to mate! Or they can mate but the offspring will not be viable or will have low fitness

Question 4

MECHANISMS OF SPECIATION

Answer 4

ALLOPATRIC SPECIATION

Sympatric speciation

Question 5

ALLOPATRIC SPECIATION

Answer 5

• Geographic separation of populations
  
  • Barrier or distance
• No gene glow between populations

Question 6

Sympatric speciation

Answer 6

• No physical barrier to separate individuals in the population
• Some other mechanism results in reproductive isolation between populations

Question 7

types of allopatric speciation

Answer 7

Dispersal—Movement of individuals away from their source popualtion

Question 8

types of allopatric speciation

Answer 8

Dispersal—Movement of individuals away from their source popualtion

Vicariance—Physical splitting of one population into two or more smaller populations due to the formation of a geographic barrier

Question 9

dispersal process

Answer 9

1. some individuals form a population disperse to a new location
   
   1. No gene flow
2. Allele frequencies of colonists begin to diverge from source population
   
   1. Genetic drift (founder effect)
   2. Natural selection (new habitat vs old habitat)
   3. Mutation
3. Pre-/postzygotic isolation develops
   
   1. Even if colonists and source population meet again… unable tor reproduce fertile offspring!

Question 10

vicariance process

Answer 10

1. population becomes separated into 2+ sub populations by a physical barrier
   
   1. Barrier stops gene flow
2. Allele frequencies of two populations begin to diverge
   
   1. Genetic drift
   2. Natural seletion
   3. Muation
3. Pre-/postzygotic isolation develops
   
   1. Even if individuals from the two populations meet again, they are unable to produce fertile offspring

Question 11

Sympatric speciation

Answer 11

evolution of new species from ancestral species while continuing to inhabit the same geographical area

can be due to disruptive selection