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BISC 120 - Lab > LAB 5 - Evolution > Flashcards

LAB 5 - Evolution Flashcards

1
Q

What was Darwin’s Theory of Evolution?

A

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

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2
Q

What is genotype?

A
  • genetic make-up of an organism

- set of alleles of an organism

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3
Q

What is the phenotype?

A
  • determined by an organism’s genetic make-up

- and environment in which organism lives

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4
Q

What is a gene?

A
  • a heritable unit that may influence a trait

- sequence of DNA

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5
Q

What is an allele?

A
  • alternative DNA sequence at the same physical gene locus

- may or may not result in different phenotypic traits

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6
Q

What is a locus?

A

-site on a chromosome where a particular gene is located

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7
Q

What is homozygous?

A

-having identical alleles for a single trait

AA or aa

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8
Q

What is heterozygous

A

-having different alleles
-dominant and recessive
Aa

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9
Q

What is the Hardy-Weinberg equation?

A

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

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10
Q

What is p^2

A

freq. of homozygous dominant individuals (genotypes)

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11
Q

what is q^2

A

freq. of homozygous recessive individuals (genotypes)

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12
Q

What is 2pq?

A

freq. of heterozygous individuals (genotypes)

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13
Q

When does evolution happen?

A

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

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14
Q

What is fitness?

A
  • ability for an organism (based on its genotype) to
    1. survive
    2. find a mate
    3. produce offspring
  • pass to next generation
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15
Q

Which beetles have greater fitness relative to the other beetles?

A

brown beetles have greater fitness relative tot he green beetles

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16
Q

What are the 3 modes of natural selection?

A
  1. stabilizing selection
  2. directional
  3. disruptive
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17
Q

What is allopatric speciation?

A

different environment

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18
Q

What is sympatric speciation?

A
  • new species evolve from a single ancestral species

- same geographic region

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19
Q

What is mutation?

A

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

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20
Q

What is genetic flow?

A
  • transfer of alleles from one pop. to another

- resulting from movement of fertile individuals or their gametes

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21
Q

What is genetic drift?

A

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

22
Q

What are 5 evolutionary agents?

A
  1. mutation
  2. gene flow (migration)
  3. genetic drift
  4. Natural selection
  5. nonrandom mating
23
Q

What are 2 types of genetic drift?

A

Bottleneck + Founder Effect

24
Q

What are 2 sources of genetic variation?

A
  1. mutation

2. gene flow

25
Q

What are the 5 conditions of Hardy-Weinberg Equilibrium?

A
  1. no mutations
  2. no gene flow
  3. no natural selection
  4. random mating
  5. large population
26
Q

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

A

PTC Exercise

27
Q

What is PTC?

A

harmless chemical with a bitter taste

28
Q

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

A

75% tasters

25% non tasters

29
Q

What does PTC resemble structurally?

A

toxic alkaloids found in some poisonous plants

30
Q

What is an example of an autosomal recessive disorder?

A

sickle cell anemia

31
Q

Which is the normal Hg allele?

A
  • S allele (normal Hg, normal RBC)

- s allele (mutated Hg, sickle RBC)

32
Q

What is the missense mutation?

A

Val instead of Glu

33
Q

What are 2 molecular clocks?

A
  • DNA sequence homology

- amino acid sequence homology

34
Q

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

A
  1. comparative anatomy
  2. comparative embryology
  3. fossil records
  4. DNA sequence homology
  5. amino acid sequence homolgy
35
Q

What is the molecular clock hypothesis based on?

A

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

36
Q

What is the molecular clock hypothesis used to do?

A
  • estimate how long ago two related organisms diverged from a common ancestor
  • when speciation occured
37
Q

What is a phylogenetic tree?

A

-graphical representation of the evolutionary relationship between taxonomic groups

38
Q

What is a clade?

A

-group that includes common ancestor and all descendents

39
Q

What is a clade also called?

A

monophyletic group

40
Q

What is natural selection?

A
  • process which fittest organisms survive, find a mate, reproduce
  • phenotypes being selected
  • genotypes being passed on
41
Q

What is evolution?

A

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

42
Q

What is macroevolution?

A
  • evolution above the species level

- new group of organisms arises form common ancestors through speciation events

43
Q

What did Hardy and Weinberg propose?

A

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

44
Q

What is incomplete dominance?

A

neither alleles in heterozygote are fully expressed

EX: PTC test

45
Q

What is stabilizing selection?

A

intermediate phenotype favored

46
Q

What is disruptive selection?

A

favors both extreme phenotypes

47
Q

What is directional selection?

A

favors one over the other extreme phenotypes

48
Q

What does s cause?

A

causes RBC to become rigid and sticky

49
Q

Which sickle cell alleles increase and which decrease?

A

S increase, s decrease

50
Q

What is the molecular clock hypothesis?

A
  • changes that occur in genetic material of isolated populations
  • due to mutations that occur at constant rates
51
Q

What is the result of molecular clock hypothesis?

A

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

52
Q

The more mismatched the pairs of nucleotides _______

A
  • the more different these DNA sequences are

- less closely related

BISC 120 - Lab (10 decks)

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