LAB 5 - Evolution

Question 1

What was Darwin’s Theory of Evolution?

Answer 1

populations evolve over the course of generations through a process of natural selection

Question 2

What is genotype?

Answer 2

• genetic make-up of an organism

- set of alleles of an organism

Question 3

What is the phenotype?

Answer 3

• determined by an organism’s genetic make-up

- and environment in which organism lives

Question 4

What is a gene?

Answer 4

• a heritable unit that may influence a trait

- sequence of DNA

Question 5

What is an allele?

Answer 5

• alternative DNA sequence at the same physical gene locus

- may or may not result in different phenotypic traits

Question 6

What is a locus?

Answer 6

-site on a chromosome where a particular gene is located

Question 7

What is homozygous?

Answer 7

-having identical alleles for a single trait

AA or aa

Question 8

What is heterozygous

Answer 8

-having different alleles
-dominant and recessive
Aa

Question 9

What is the Hardy-Weinberg equation?

Answer 9

p^2 + 2pq + q^2 = 1

Question 10

What is p^2

Answer 10

freq. of homozygous dominant individuals (genotypes)

Question 11

what is q^2

Answer 11

freq. of homozygous recessive individuals (genotypes)

Question 12

What is 2pq?

Answer 12

freq. of heterozygous individuals (genotypes)

Question 13

When does evolution happen?

Answer 13

-when there is a change in gene frequency within a population over time

Question 14

What is fitness?

Answer 14

• ability for an organism (based on its genotype) to
  1. survive
  2. find a mate
  3. produce offspring
• pass to next generation

Question 15

Which beetles have greater fitness relative to the other beetles?

Answer 15

brown beetles have greater fitness relative tot he green beetles

Question 16

What are the 3 modes of natural selection?

Answer 16

1. stabilizing selection
2. directional
3. disruptive

Question 17

What is allopatric speciation?

Answer 17

different environment

Question 18

What is sympatric speciation?

Answer 18

• new species evolve from a single ancestral species

- same geographic region

Question 19

What is mutation?

Answer 19

-a change in the nucleotide sequence of an organism’s DNA

Question 20

What is genetic flow?

Answer 20

• transfer of alleles from one pop. to another

- resulting from movement of fertile individuals or their gametes

Question 21

What is genetic drift?

Answer 21

-chance events cause unpredictable fluctuations of allele frequencies from one generation tot he next

Question 22

What are 5 evolutionary agents?

Answer 22

1. mutation
2. gene flow (migration)
3. genetic drift
4. Natural selection
5. nonrandom mating

Question 23

What are 2 types of genetic drift?

Answer 23

Bottleneck + Founder Effect

Question 24

What are 2 sources of genetic variation?

Answer 24

1. mutation

2. gene flow

Question 25

What are the 5 conditions of Hardy-Weinberg Equilibrium?

Answer 25

1. no mutations 2. no gene flow 3. no natural selection 4. random mating 5. large population

Question 26

What experiment in lab was done to test incomplete vs. complete dominance?

Answer 26

PTC Exercise

Question 27

What is PTC?

Answer 27

harmless chemical with a bitter taste

Question 28

What is the percentage of people who can taste PTC and those who can't?

Answer 28

75% tasters | 25% non tasters

Question 29

What does PTC resemble structurally?

Answer 29

toxic alkaloids found in some poisonous plants

Question 30

What is an example of an autosomal recessive disorder?

Answer 30

sickle cell anemia

Question 31

Which is the normal Hg allele?

Answer 31

- S allele (normal Hg, normal RBC) | - s allele (mutated Hg, sickle RBC)

Question 32

What is the missense mutation?

Answer 32

Val instead of Glu

Question 33

What are 2 molecular clocks?

Answer 33

- DNA sequence homology | - amino acid sequence homology

Question 34

What are 5 things taht today's species are classified by into phylogenetic taxa?

Answer 34

1. comparative anatomy 2. comparative embryology 3. fossil records 4. DNA sequence homology 5. amino acid sequence homolgy

Question 35

What is the molecular clock hypothesis based on?

Answer 35

theory that specific DNA sequences(or proteins they encode) spontaneously mutate at constant rates

Question 36

What is the molecular clock hypothesis used to do?

Answer 36

- estimate how long ago two related organisms diverged from a common ancestor - when speciation occured

Question 37

What is a phylogenetic tree?

Answer 37

-graphical representation of the evolutionary relationship between taxonomic groups

Question 38

What is a clade?

Answer 38

-group that includes common ancestor and all descendents

Question 39

What is a clade also called?

Answer 39

monophyletic group

Question 40

What is natural selection?

Answer 40

- process which fittest organisms survive, find a mate, reproduce - phenotypes being selected - genotypes being passed on

Question 41

What is evolution?

Answer 41

-change in the frequency of alleles in the gene pool from one generation to the next

Question 42

What is macroevolution?

Answer 42

- evolution above the species level | - new group of organisms arises form common ancestors through speciation events

Question 43

What did Hardy and Weinberg propose?

Answer 43

-frequencies of alleles in a population will stay constant/not change

Question 44

What is incomplete dominance?

Answer 44

neither alleles in heterozygote are fully expressed | EX: PTC test

Question 45

What is stabilizing selection?

Answer 45

intermediate phenotype favored

Question 46

What is disruptive selection?

Answer 46

favors both extreme phenotypes

Question 47

What is directional selection?

Answer 47

favors one over the other extreme phenotypes

Question 48

What does s cause?

Answer 48

causes RBC to become rigid and sticky

Question 49

Which sickle cell alleles increase and which decrease?

Answer 49

S increase, s decrease

Question 50

What is the molecular clock hypothesis?

Answer 50

- changes that occur in genetic material of isolated populations - due to mutations that occur at constant rates

Question 51

What is the result of molecular clock hypothesis?

Answer 51

-scientists can determine approx. point when 2 species diverged from common ancestor (when speciation occurred)

Question 52

The more mismatched the pairs of nucleotides _______

Answer 52

- the more different these DNA sequences are | - less closely related