codon learning exam 6

Question 1

fitness

Answer 1

the ability of an individual to produce viable offspring and passes its alleles along

Question 2

mutation

Answer 2

any change in the DNA
-mutations can create new alleles

Question 3

evolution three processes

Answer 3

1) heritable variation exists in populations and there are a variety of alleles at genes (caused by a mutation)
2) not all individuals of the population produce the same number of viable offspring, different reproductive success (fitness)
3) frequencies of alleles change through evolution

Question 4

evolution vs natural selection

Answer 4

evolution: defined as a change in allele frequencies
natural selection: occurs when certain alleles are associated with higher or lower reproductive success

Question 5

artificial selection

Answer 5

humans control and select which individuals will be the parents of the next generation

Question 6

directional selection graph

Answer 6

bell shaped
-trait moves in one direction across the x-axis

Question 7

stabling selection

Answer 7

bell shaped graph moves in ward (the tip of graph moves up the y axis and grows closer on the x axis)

Question 8

directional selection 2 key impacts

Answer 8

1) avg changes, because individuals with one extreme have higher fitness while individuals with lower extreme have lower fitness
2) amount of overall variation decreases because the alleles are being eliminated

Question 9

stabilizing selection 2 key impacts

Answer 9

1) avg does NOT change b/c individuals with intermediate values of trait have the highest fitness
2) amount of overall variation decreases b/c alleles associated with both extremes are being eliminated

Question 10

directional selection

Answer 10

natural selection that favors the extreme phenotype

Question 11

stabilizing selection

Answer 11

natural selection that favors the average phenotype in the population and acts against the extreme phenotypes

Question 12

biological evolution

Answer 12

change in the frequencies of alleles in a population over time

Question 13

small population sizes typically have

Answer 13

low genetic diversity

Question 14

genetic drift

Answer 14

any change in allele frequencies that is due to chance

Question 15

founder events

Answer 15

-relatively small number of individuals disperse to a new habitat and found a new population because the allele frequencies would be different from the bigger population

Question 16

genetic bottlenecks

Answer 16

-species undergoes a rapid decrease in population size and results in random changes in the allele

Question 17

genetic drift 3 main points

Answer 17

1) it is more important in smaller populations than in large
2) it reduces genetic variation which leads to fixation and loss of alleles
3) a wide array of events can cause genetic drift

Question 18

speciation

Answer 18

process that creates new species of organisms
-splitting event
–2 step process w genetic isolation and genetic divergence

Question 19

species

Answer 19

population that is genetically isolated from others and is under effect of natural selection, genetic drift, and mutation

Question 20

population

Answer 20

group of individuals from the same geographic region that regularly mate together

Question 21

root of phylogenetic tree

Answer 21

-base, root represents the population that is the ancestor of the others in the tree

Question 22

branch in phylogenetic tree

Answer 22

specific species
-horizontal line

Question 23

node

Answer 23

where branch splits into 2 during a speciation event

Question 24

tips

Answer 24

ends of the tree with a taxon, or name of group, at the end of it

Question 25

monophyletic group

Answer 25

group consists of an ancestor and all of its descendants

Question 26

homoplasty

Answer 26

similarity in traits that is due to independent evolution due to common ancestry

Question 27

synapomorphy

Answer 27

trait that one group has that no one else does. Synapomorphies define monophyletic groups.

Question 28

out group

Answer 28

Any lineage that is not part of the monophyletic group that is the focus of a phylogenetic tree.

Question 29

parsimony

Answer 29

A criterion in logic that states that the simplest explanation is the most likely to be correct.

Question 30

adaptive radiation

Answer 30

rapid diversification of a lineage into large number of species with each adaptation that allows them to exploit different resources and habitats

Question 31

niche

Answer 31

range of resources and environments that a species uses.