evolution

Question 1

describe the 3 modes of species origin

Answer 1

• anagenesis( 1 species changes over time)
• cladogenesis( branching of species)
  -chronospecies ( arbitrarily divided by time)

Question 1

describe the 3 types of speciation

Answer 1

• allopatric- physically separated
• parapatric- partially seperated, some gene flow
• sympatric- not separated

Question 2

describe the 3 prerequisites for evolution

Answer 2

• genetic variation
• recombination ( sexual reproduction, crossing over)
• gene flow

Question 3

describe the postulates of natural selection

Answer 3

1) genes are heritable
2) there’s is competition for resources
3) all individuals have variation

Question 4

describe the 3 types/patterns of natural selection

Answer 4

• stabilizing
• disruptive/diversifying
• directional

Question 5

What is assortive mating

Answer 5

non randomized mating:
positive: mates with similar traits: i.e. size
negative: mates with opposite traits: i.e. pheromones’

Question 6

what are the four mechanisms for evolution
bonus: what is gene flow called in humans

Answer 6

1) natural selection
2) mutation
3) gene flow ( in humans, admixture)
4) genetic drift

Question 7

what are the two species concepts and who made them

Answer 7

MAYR- biological species concept: group of actually or potential interbreeding pops reproductively isolated from other species
CRACRAFT- phylogenic species concept: smallest population with shared parental pattern of ancestry, genetic not behavioral

Question 8

define a subspecies

Answer 8

geographically isolated pops with unique phenotypes that can still interbreed

Question 9

what is the difference between an analogous and homologous trait

Answer 9

analogous- similar due to function ( convergent evolution)
homologous- similar due to shared ancestry

Question 10

what is the difference between a primitive and derived trait, and what are the fancy names for them

Answer 10

primitive ( pleisiomorphy) - shared with common ancestor
derived ( apomorphy)- not shared with common ancestry

Question 11

what type of trait do we look at in a cladogram, and which dont we use

Answer 11

we use synapomorphy, or when clades share a derived trait. We dont use apomorphy, symplesiomorphy, or homoplasy ( convergent evolution)

Question 12

what is the better version of a cladogram, and what does it do different?

Answer 12

Phylogeny- includes time and level of divergence since split