Lecture 19

Question 1

Adaptive/ fitness landscape

Answer 1

a = mutations, B = optimisation, c = local optima

Mutation explores the possibiliesi,NS defines traits that are adaptive

Question 2

Mullers rachet

Answer 2

accumulation of deleterious mutations which can be removed by sexual reproduction and recombination

Question 3

Role of NS

Answer 3

If rate of mutation or drift balances selective pressure then it might appear that population isn’t under selection

Question 4

Adaptation definition

Answer 4

occurs when an organisms displays traits that allow it to live in an environment and other factors permit this
Competition limit niche

Question 5

What promotes adaptation

Answer 5

Anything that gives NS more to work with in local populations
Moderate mutation rates
small amount of gene flow
directional selection
developmental competence

Question 6

What prevents adaptation

Answer 6

excessive gene flow between populations may swamp NS

inbreeding, genetic drift, large amount of gene flow, stabilising selection

Question 7

Developmental possibilities

Answer 7

Common basic body plan for different groups of organisms - variations of a theme

Question 8

Microevolution to macroevolution

Answer 8

Adaptation could proceed through step wise changes in developmental patterns - major changes (saltation)
Saltation - new body plans come into being as a result of sudden discontinuous and crucial changes (macro mutations_

Question 9

Argument of micro-macro evolution characterised by two extremes:

Answer 9

Gradualism - occurs uniformly and by steady and gradual transformation
Punctuated - equilibrium - evolution marked by isolated episodes of rapid speciation between long periods of little or no change

Question 10

Homologous structures

Answer 10

allow us to infer functions in extinct species

similarity by common descent, similar form, function and developmental trajectory

Question 11

Analogous structures in unrelated species

Answer 11

great care must be taken in stabilising functions of traits in extinct species
different ancestry, developmental trajectory and same function

Question 12

Co-opted traits and exaptation

Answer 12

Gould and Vrba suggested exaltation for adaptation that involved new uses for existing traits

Question 13

Genetic hitchhiking

Answer 13

traits may be selected “for” because they are linked to something else - occurs when allele freq changes because its near another gene that is undergoing selection

Question 14

What are evolutionary solutions?

Answer 14

imperfect not optimal

Question 15

Dollos law

Answer 15

evolutions is not reversible i.e. structures discarded during evolution do not reappear in a given line of organisms

Question 16

criticisms of apatationist agena

Answer 16

Cain Vs Gould and Lewontin

Some are just selective neutral - not every trait has to have an adaptive function