Evolution Natural Selection Flashcards

1
Q

What is natural selection?

A

The slight genetic variation among individuals which has an impact on their individual survival and consequently the number of offspring it will produce.

Acts on the phenotypical aspect of the individuals within a population

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2
Q

What is artificial selection?

A

These are human-made genetic modifications.

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3
Q

What is a phenotype?

A

Physical expression of genes
ex. B=brown eyes b= blue eyes
BB and Bb=brown eyes bb=blue eyes

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4
Q

What is a genotype?

A

The genetic constitution that governs a trait (not related to physical appearance)

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5
Q

What is evolution?

A

Any change in the frequency of a genotype

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6
Q

What is a gene pool?

A

The sum of the different alleles (variation) that produce different phenotypes

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7
Q

What is a population?

A

A locally interbreeding group within a geographic population

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8
Q

How to calculate an allele frequency

A

2 x the number of copies of the said allele + the number of heterozygous copies/ 2 x total of the population

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9
Q

What is the genotype frequency?

A

individuals with the genotype/ total# of individuals in the population

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10
Q

What is genetic structure?

A

The frequencies of different alleles at each locus and the frequencies of different genotypes

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11
Q

What is Hardy Weinberg equilibrium?

A

A population in which the frequencies of alleles and genotypes do not change from generation to generation (no evolution).

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12
Q

What are the requirements for a population to be considered to be in Hardy-Weinberg equilibrium?

A
  • Mating random
  • Population size is very large or infinite
  • There is no migration between populations
  • There is no mutation
  • Natural selection does not affect the alleles under consideration

If after one generation all of these requirements are met then it is considered to be in Hardy-Weinberg equilibrium

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13
Q

What is the Hardy-Weinberg equation?

A

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

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14
Q

What are the known evolutionary agents?

A
  • mutation
  • Gene flow
  • Genetic drift
  • Nonrandom mating
  • Natural selection
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15
Q

What are mutations?

A

Origin of genetic variation. A mutation is any change in an organism’s DNA

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16
Q

What are the types of mutations?

A

Harmful: Disadvantage to the individual (disease, death, etc.)

Neutral: Doesn’t have any effect in the individual’s life

Advantageous: Can help survive in certain environments and take over the population, replacing the useless traits

17
Q

What is gene flow?

A

When individuals migrate to another population and breed in their new location.

Immigrants may add new alleles or may change their frequencies if they come from a population with different allele frequencies

18
Q

What is genetic drift?

A

Random loss of individuals and the alleles they possess

More powerful than mutation and gene flow

19
Q

What is a population bottleneck?

A

A small number of individuals, in a population, survive

1st type of genetic drift

20
Q

What is the founder effect?

A

A few pioneering individuals leave the original population and colonize a new region creating a new population

2nd type of genetic drift

21
Q

What is non-random mating?

A

When individuals make either more often with individuals of the same genotype OR more often with individuals of a different genotype

Ex. :If a genotype reproduces more with the same genotype= homozygous genotype overrepresented

22
Q

What is natural selection?

A

Adapting to an environment. Advantages may be produced.

23
Q

What is fitness?

A

The ability of an organism to survive and pass on its genes to the next generation

24
Q

What are the characters that affect natural selection?

A
  • Stabilizing selection
  • Directional selection
  • Disruptive selection
25
Q

What is stabilizing selection?

A

Preservation of the characteristics of a population by favoring average individuals (heterozygous)

26
Q

What is directional selection?

A

Changes the characteristics of a population by favoring individuals that vary in one direction from the mean of the population

27
Q

What is disruptive selection?

A

Changes characteristics of a population by favoring characteristics of a population in both directions from the mean of the population