Chapter 11.6

Question 1

5 mechanisms of evolution ( changes in allele frequency)

Answer 1

1. Natural selection ( responsible for adaptations that enhance survival and reproduction

2. MUtations

3, Genetic Drift

4. nonrandom mating

5 gene flow

Question 2

MUTATIONS

Answer 2

.fuels evolution

. a change in an oraganisms DNA squence introduces a new allelle to a population

Question 3

Why are mutations the raw materials for evolution

Answer 3

because genes contribute to phenotypes and natural selection acts on phenotypes.

. It is independentant of wheter or not it would benefit the organism

e.g if an organisms develops a n allele that is beneficial to its environment it would happen before the exposure to the new environment

A mutation affects evolution only if subsequent generations inherit

Question 4

A mutation can only be inherited if ( in a multicellular organism)

Answer 4

only if it arises in a germ cell

Question 5

A mutation in a bacteri is inherited how

Answer 5

mutated cells gives rise to mutant offsprings 9 if the mutation does not prevent reproduction)

. It increases genetic diversity

Question 6

GENETIC DRIFT

Answer 6

is a change in allele frequencies that occurs purely by chance

.unlike mutation, which increases diversity, genetic drift tends to eliminate alleles from population

Question 7

The root of genetic drift is

Answer 7

sampling error ( a mutation does not get inherited soley do to chance and is eventually wipe out)

occurs mostly in small populations

Question 8

2 causes of genetic drift

Answer 8

1. Founder effect
2. Bottle neck effect

Question 9

FOUNDER EFFECT

Answer 9

Which occurs when a small group of individuals leaves its home population and establishes a new,isolated settlement

allele frequencies( rare ones) are not the same as the original population.Traits that once were rare among the new group may become more frequent or dissappear

Question 10

BOTTLENECK EFFECT

Answer 10

A type of genetic drift when a population drops rapidly over a short period of time causing the loss of many alleles that were present in the larger ancestral population at random

Even if the remaing population mate the loss of genetic diversity is permanent

may result in genetic uniformity that might them extinct in just one change in the environment

eg. overhunting, habitat loss, great disaster

Question 11

RANDOM MATING

Answer 11

each individual have anequal chance of mating with any other memeber of that population

Question 12

NON RANDOM MATING

Answer 12

mating is rarely random

it concentrates alleles locally

egs. human mating. artificial selection ( mating is done by preference)

Question 13

GENE FLOW

Answer 13

moves alleles among populations

Migration is the most common way

It can counteract the effects of both natural selection and genetic drift