Chapters 20-25

Question 1

Define polymorphic locus

Answer 1

if one allele has very high frequency then the other alleles are unlikely to be observed, unless the sample size is very large

Question 2

Define Hardy-Weinberg equilibrium

Answer 2

Proportions of genotypes do not change in a population if

• no mutation takes place
• no genes are transferred to or from other sources random mating is occurring, the population size is very large, no selection occurs

Question 3

What is the founder principle and bottleneck effect

Answer 3

When a species is nearly hunted to extinction resulting the species having a loss in almost all of its genetic variation an example: would be the near extinction of the northern elephant seal in the 19th century

Question 4

what is natural selection

Answer 4

the organism that is most fit will survive and pass on its genes to next generation

Question 5

Define Stabilizing

Answer 5

acts to eliminate both extremes

Question 6

define Disruptive

Answer 6

acts to eliminate intermediate types

Question 7

define Directional

Answer 7

acts to eliminate one extreme

Question 8

give an example of heterozygote advantage

Answer 8

Sickle cell anemia in Africa to protect from malaria

Question 9

Why did Darwin’s finches have different beaks

Answer 9

Each beak size was better adapt to break certain seeds and accessing flowers

Question 10

What is industrial melanism

Answer 10

phenomenon in which darker individuals come to predominate over lighter ones (i.e., moths)

Question 11

Darwin’s finches and industrial Melanism are examples of what

Answer 11

Natural selection/ directional selection

Question 12

most highly artificially selected crop plant

Answer 12

corn

Question 13

What links Archaeopteryx to birds and dinosaurs

Answer 13

Possesses some ancestral traits and some traits of present day birds

Question 14

Define Vestigial structures

Answer 14

structures that have little to no use that are left from evolution. (appendix)

Question 15

Define Derived characters

Answer 15

Similarity that is inherited from the most recent common ancestor of an entire group

Question 16

Outgroups in morphological data and in a phylogeny

Answer 16

An organism that is clearly similar but not related to the clade

Question 17

Define clade

Answer 17

Species that share a common ancestor as indicated by shared characteristics

Question 18

How much difference there is between human and chimp DNA

Answer 18

.106%

Question 19

What has happened to some of the OR genes in humans

Answer 19

Loss of gene function, Inactivation best explanation for our reduced sense of smell
60% of human OR genes are pseudogenes Sequences of DNA that are very similar to functional genes but do not produce a functional product Likely explanation is we rely on other senses so selection pressure against loss of OR genes reduced

Question 20

Define homoplastic structure

Answer 20

Homoplastic (analogues) structures, same or similar functions, arose independently