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BIO370: Evolution > Lecture 3 > Flashcards

Lecture 3 Flashcards

1
Q

What are different components of logistic growth?

A
  1. Initial exponential growth
  2. Decline in growth rate (due to resource limitations and (in)direct competition)
  3. Zero growth rate at the carrying capacity (i.e. the number of organisms that can be supported without environmental degredation)
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2
Q

What conditions are needed for natural selection?

A
  1. Reproduction
  2. Heredity
  3. Variation in heritable traits
  4. Variation in fitness
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3
Q

What is the definition of fitness?

A

Relative reproductive success due to a heritable trait

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4
Q

What is needed to produce a phenotype?

A

Phenotype = Genotype + Environment

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5
Q

What is the definition of a phenotype?

A

External characteristics of an individual that selection can act on

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6
Q

What is the definition of a genotype?

A

Sets of genes (heritable “instruction”) carried by the individual; the genetic makeup

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7
Q

What statistics are used to describe the frequency distribution of a heritable trait?

A
  1. Average
  2. Variance
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8
Q

What is the definition of statistical average?

A

The measure of the central tendency of a population

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9
Q

What is the definition of statistical variance?

A

The measure of the spread around the average

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10
Q

What are the 2 categories of variation?

A
  1. Continuous variation
  2. Discrete variation
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11
Q

What is the definition of continuous variation?

A

Types of variations are distributed on a continuum (quantitative traits); the combined effect of many genes (i.e. polygenic); environment influences trait variation

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12
Q

What is the definition of discrete polymorphisms?

A

Related to multiple forms of a gene that can exist (qualitative traits); based on a single major gene (i.e. monogenic); environment plays no role

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13
Q

What is the definition of heritability?

A

The fraction of the total phenotypic variance that is attributable to genetic differences among individuals in a given population

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14
Q

What is the significance of heritability?

A

Heritability is evidence of

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15
Q

Variance equation:

A

Vp = Vg + Ve + Vg*e

Vp = tot phenotypic variance

Vg = variance due to differences in genetic factors

Ve = variation due to environmental influence

Vg*e = variation due to interactions between genes and the environment

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16
Q

Heritability equation:

A

H2 = Vg/Vp

17
Q

What does low heritability mean?

A
  1. Little genetic variation in the population
  2. Greater environmental induced variation than genetic control
18
Q

What does it mean when H2 is equal to 0?

A

There is no genetic variation (still a heritable trait and has a genetic basis) and the population is under fixation. HOWEVER, environmental induced variation can still occur

19
Q

What are the different types of selection?

A
  1. Directional selection
  2. Stabilizing selection
  3. Disruptive selection
  4. No selection
20
Q

What is the definition of directional selection?

A

A mode of natural selection in which an extreme phenotype is favored over the others, causing allele frequencies to shift over time in that direction

21
Q

What is the definition of stabilizing selection?

A

A mode of natural selection in which the population mean stabilizes on a particular non-extreme (median) trait value

22
Q

What is the definition of disruptive selection?

A

A mode of natural selection in which extreme values for a trait are favored over the intermediate value

23
Q

What is the definition of heredity?

A

Refers to inheritance (i.e. the transfer of genetic information from parent to offspring)

24
Q

What is the definition of population think?

A

The theory that regularities that occur in populations such as extiction, speciation, and adaptation emerge from the collective activities of individuals

25
Q

What is the definition of differential survivorship?

A

Shows how some survive better than others - population starts off with 50% A and 50% B, but when observed at a different time, some of A die while B remains the same

26
Q

What is the definition of differential reproduction?

A

Starting with a population balanced 50/50, both increase in number, but B adds more to the population (increases more in frequency in relation to A)

27
Q

What is the definition of biological evolution?

A

An inherited change in a group of variable organisms through time

28
Q

What is GWAS (Genome-Wide Association Study) used for?

A

GWAS looks at genetic variants underlying a trait variation, and determines which are statistically significant and which are not

29
Q

How are SNPs used in GWAS?

A

SNPs are used to correlate genetic variations with phenotypic variations

30
Q

What type of study is GWAS?

A

Observational study

31
Q

What can serve as a result for disruptive selection?

A

Disruptive selection often occurs during speciation events

BIO370: Evolution (8 decks)

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