- genetic make-up of an organism - set of alleles of an organism

- a heritable unit that may influence a trait - sequence of DNA

- alternative DNA sequence at the same physical gene locus - may or may not result in different phenotypic traits

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

LAB 5 - Evolution Flashcards by Jenna Chin

What was Darwin’s Theory of Evolution?

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

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What is genotype?

genetic make-up of an organism

- set of alleles of an organism

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What is the phenotype?

determined by an organism’s genetic make-up

- and environment in which organism lives

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What is a gene?

a heritable unit that may influence a trait

- sequence of DNA

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What is an allele?

alternative DNA sequence at the same physical gene locus

- may or may not result in different phenotypic traits

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What is a locus?

-site on a chromosome where a particular gene is located

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What is homozygous?

-having identical alleles for a single trait

AA or aa

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What is heterozygous

-having different alleles
-dominant and recessive
Aa

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What is the Hardy-Weinberg equation?

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

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What is p^2

freq. of homozygous dominant individuals (genotypes)

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what is q^2

freq. of homozygous recessive individuals (genotypes)

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What is 2pq?

freq. of heterozygous individuals (genotypes)

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When does evolution happen?

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

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What is fitness?

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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Which beetles have greater fitness relative to the other beetles?

brown beetles have greater fitness relative tot he green beetles

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What are the 3 modes of natural selection?

stabilizing selection
directional
disruptive

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What is allopatric speciation?

different environment

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What is sympatric speciation?

new species evolve from a single ancestral species

- same geographic region

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What is mutation?

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

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What is genetic flow?

transfer of alleles from one pop. to another

- resulting from movement of fertile individuals or their gametes

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What is genetic drift?

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

What are 5 evolutionary agents?

mutation
gene flow (migration)
genetic drift
Natural selection
nonrandom mating

What are 2 types of genetic drift?

Bottleneck + Founder Effect

What are 2 sources of genetic variation?

mutation

2. gene flow

What are the 5 conditions of Hardy-Weinberg Equilibrium?

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

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

PTC Exercise

What is PTC?

harmless chemical with a bitter taste

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

75% tasters | 25% non tasters

What does PTC resemble structurally?

toxic alkaloids found in some poisonous plants

What is an example of an autosomal recessive disorder?

sickle cell anemia

Which is the normal Hg allele?

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

What is the missense mutation?

Val instead of Glu

What are 2 molecular clocks?

- DNA sequence homology | - amino acid sequence homology

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

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

What is the molecular clock hypothesis based on?

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

What is the molecular clock hypothesis used to do?

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

What is a phylogenetic tree?

-graphical representation of the evolutionary relationship between taxonomic groups

What is a clade?

-group that includes common ancestor and all descendents

What is a clade also called?

monophyletic group

What is natural selection?

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

What is evolution?

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

What is macroevolution?

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

What did Hardy and Weinberg propose?

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

What is incomplete dominance?

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

What is stabilizing selection?

intermediate phenotype favored

What is disruptive selection?

favors both extreme phenotypes

What is directional selection?

favors one over the other extreme phenotypes

What does s cause?

causes RBC to become rigid and sticky

Which sickle cell alleles increase and which decrease?

S increase, s decrease

What is the molecular clock hypothesis?

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

What is the result of molecular clock hypothesis?

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

The more mismatched the pairs of nucleotides _______

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