Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

general bio 2024 > Lecture 13 > Flashcards

Lecture 13 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Where does evolution occurs?

A

In populations not individuals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens when an individual is born with a variation beneficial for survival and aiding in their reproduction?

A

That varying trait will get passed down from generation to generation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is the evolutionary impact of natural selection apparent?

A

In the changes in a population of organisms over time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mutation and sexual reproduction

A

Processes that produce the variation in gene pools that contributes to differences among individuals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does variation in individual genotype leads to?

A

Variation in individual phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Is all phenotypic variation heritable?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

On what kind of variation can natural selection act on?

A

A variation with a genetic component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Natural selection

A
  • Differential contribution of offspring to the next generation by various genetic types belonging to the same population
  • differential success in reproduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the result of natural selection?

A
  • Change in the genetic makeup (ex.: frequency of alleles) of the population so evolution
  • certain alleles being passed to the next generation in greater proportions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What can natural selection alter?

A

The frequency distribution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In what 3 ways can natural selection alter the frequency distribution of heritable traits?

A
  • Directional selection
  • disruptive selection
  • stabilizing selection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

modes of selection

A

3 ways in which natural selection alter the frequency distribution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How are the modes of selection chosen for natural selection and the frequency distribution?

A

It depends on which phenotypes in a population are favored

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Directional selection

A
  • Favors individuals possessing extreme values of a trait (like fur color in mouse or long necks in giraffes) that causes the population to move in a particular direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When is directional selection most common?

A
  • During periods of environmental change
  • when members of a population migrate to a new habitat with different environment conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Disruptive selection

A
  • Occurs when environmental conditions favors individuals at our extremes of the phenotypic range over those with intermediate phenotypes
  • may occur in an area that provides different resources
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Stabilizing selection

A
  • Favors intermediate variants
  • acts against extreme phenotypes
  • acts against individuals who deviate too fair from the average
  • favors the average
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Example of stabilizing selection: sizes in lizard

A
  • Large lizards may be subject to predation
  • small lizards have a had time defending territories
  • natural selection favors the average
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

On what does natural selection acts?

A

Phenotypes

20
Q

Compare the genotype and phenotype of individual AA and Aa

A
  • Different genotypes
  • same phenotype (A)
  • outwardly the same
21
Q

Compare the genotype and phenotype of individual aa to Aa and AA

A
  • aa are different phenotypically
  • may survive and reproduce bitter than Aindividuals
22
Q

Gene pool

A

Sum of all copies of all alleles at all loci in a population

23
Q

Allele frequencies

A
  • Proportion in the gene pool
  • estimated by counting alleles in a sample of individuals
24
Q

What is p?

A

Frequencies of dominant alleles

25
Q

What is q?

A

Frequency of recessive alleles

26
Q

How do you find q?

A

Nb of copies of a in the population/sum of alleles in the population

27
Q

How do you find p?

A

Nb of copies of A in the population/sum of alleles in the population

28
Q

Hardy-weinberg equilibrium

A

Describes a model situation in which allele frequencies do not change over time

29
Q

Hardy-weinberg equation

A

p^2 + 2pq + q^2

30
Q

Equations to figure out allele and genotype frequencies in a population

A

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

31
Q

Conditions for a population to be evolving

A
  • Natural selection
  • non random mating
  • mutation
  • gene flow
  • genetic drift
32
Q

What happens if any of the evolution conditions take place in a population?

A

It is not in hardy-weinberg equilibrium

33
Q

Genetic drift

A
  • Affects the genetic makeup of the populations
  • is random unlike natural selection
  • doesn’t work to produce adaptations
  • one allele may be eliminated purely by chance
  • the smaller a sample, the greater the chance of deviation from a predicted result
34
Q

Genetic bottlenecks

A
  • Occurs when the number of individuals in a large population one drastically reduced by a disaster
  • by chance, some alleles may be overrepresented
  • others are underrepresented among the survivors
  • some alleles may be eliminated altogether
35
Q

Population bottleneck

A

-Happens when populations are reduced to a small number of individuals
- genetuc drift can reduce genetic variation
- will continue to change the gene pool until the population is large enough to eliminate the effect of chance fluctuations

36
Q

Founder effect

A
  • occurs when a few individuals become isolated from a larger population
  • can affect allele frequencies Ina population
  • small fraction of a population establishes a new colony
  • they bring with them only a small fraction of the genetic variability in the original population
  • allele Fred of newly found population different from parent population
37
Q

What is equivalent to the founder effect?

A

Bottleneck

38
Q

What does genetic drift also affects?

A
  • Small populations that colonize a few region
  • colonizing population unlikely to have all the alleles present in the whole population
39
Q

Gene flow

A
  • Consists of the movement of alleles among populations
  • tends to reduce differences between populations over time
  • more likely then mutation to alter alle le frequencies directly
  • can increase and decrease fitness in a population
40
Q

Movement of alleles in gene flow

A
  • Transferred through the movement of partile individuals or gametes (like pollen)
  • move from one population to another (increase genetic variability)
41
Q

Neutral variation

A
  • Generic variation that appears to worker no selective advantage
  • neutral alleles serve as a reserve of allelic variation
42
Q

Examples of neutral variation

A
  • Fingerprints
  • eye color
43
Q

Sexual selection

A
  • Natural selection for matin success
  • result in a sexual dimorphism
44
Q

Sexual dimorphism

A

Marked differences between the sexes in secondary sexual characteristics

45
Q

Intrasexual selection

A
  • direct competition among individuals of one sex (usually males) for mates of the opposite sex
46
Q

Intersexual selection

A
  • Occurs when individuals of one sex (usually females) are choosy in selecting their mates from individual of the other sex
  • When a female chooses a mate base on appearance or behavior, she perpetuates the alleles that caused her to make that choice

general bio 2024 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions