comparative method

Question 1

COMPARATIVE METHOD

Answer 1

studies the distribution of biological traits
across different taxa

way to understand the large-
scale effects of natural selection

way to understand the large-
scale effects of natural selection and

Compare traits across species, look for trends and patterns

Question 2

STEPS TO USE THE COMPARATIVE METHOD

Answer 2

1. Reconstruct the phylogenetic relationships
2. Obtain data on one or more characters of interest
3. Map trait(s) onto tree and infer how many changes and where
4. Compare species and/or traits by using statistical methods

Question 3

(discrete) Mk (Markov k-state 1 parameter) model:

Answer 3

Evolutionary changes between k states of a character

Question 4

Markov process:

Answer 4

change
depends on current state only

every state is equally likely

Question 5

EVOLUTION OF CONTINUOUS TRAITS

Answer 5

brownian motion model (random)

ornstein-uhlenbeck model (evolve toward optimum)

Question 6

Classic statistical methods assume that

Answer 6

data is independent (species are not)