4C

Question 1

what is evolutionary process

how do this process occur?

Answer 1

The evolutionary process= Changes in the proportion of different variants

Phenotype ->(drift, natural selection)-> Reproductive
Success (fitness)->Genes
->Mutation-> phenotype (its like a triangle)

BY GENETIC DRIFT

Question 2

can affect the frequencies of
genetic variants and traits during life cycle,
especially mating and survival

Answer 2

RAndom processes

Question 3

From an evolutionary perspective, such events will
be random if their probability of occurrence is not
affected by an individuals’ ______________

Answer 3

phenotype

Question 4

Genetic drift
What is it and what causes it?

Answer 4

• Changes in allele frequency due to chance (“sampling error”) in finite
  populations, especially very small population

Question 5

The consequences of random processes are
more significant for _____ ______ than for
______ population

Answer 5

small populations than for large populations

Question 6

Genetic drift causes _______ in finite populations

Answer 6

evolution

Question 7

Genetic drift results from …

Answer 7

random sampling error and sampling error
is higher with a smaller sample

Question 8

The consequences of ______ ______ are more significant for
small populations than for large
populations

Answer 8

random processes

Question 9

the consequence is

Answer 9

fixation or extinction of a allele

Question 10

Genetic drift ______ genetic variation in a population

Answer 10

reduces

Question 11

What is bottlenecks

Answer 11

temporary reductions in population size cause drift, reduce
genetic variation, and cause genetic differences between populations –
significant conservation implications

Question 12

Founder effect

Answer 12

cause genetic drift, new populations started by a small number of individuals that left

Question 13

in southeast asia

Answer 13

humans interbreed with denisovans 50000 yrs ago

Question 14

what is phylogeny?
who do all non africans descend from
what reflects founder effect?

Answer 14

Phylogeny: human populations closely
related to neighbours.
* All non-Africans descend from a small
population of humans who lived in
Ethiopia.
* Decline in genetic diversity reflects
founder effects

Question 15

Nature of genetic drift results in changes in __________ ________, even if the initial
frequencies are ___ ____

Answer 15

,allele frequences , the same

Question 16

Key concepts:
Genetic drift causes reductions in ______ ______ - variation is lost more
rapidly in ____ populations (bottlenecks and founder events)
Genetic drift causes population ______

Answer 16

genetic variation, small, divergence

Question 17

Interbreeding
Does interbreeding violate or agree with HWE assumptions?
what causes it?

Answer 17

A special case of nonrandom mating (e.g. a violation of HWE
assumptions)
interbreeding have consequences fro the overall fitness of the population
* What causes it?
– Small populations (absolute, geographic or cultural)
– Mating system (mating with relatives, ie cousins

Question 17

Non random mating -
interbreeding -
outbreeding-
assortative mating -

Answer 17

Mating individuals are more closely related or less closely related than those drawn
by chance from a random mating population
* inbreeding - mating with relatives
* outbreeding - mating with individuals more distantly related (i.e. non-relatives)
* assortative mating - individuals with similar genotypes and/or phenotypes mate
with one another more frequently than would be expected under a random mating
pattern (e.g., body size)

Question 18

Although inbreeding affects _____ frequencies, it does not ….

Answer 18

genotype frequencies, alter allele frequencies, by itself:
example: self-crosses- ultimate source of interbreeding

Question 19

results in reduced fitness

Answer 19

Interbreeding depression

Question 20

What is interbreeding depression?

Answer 20

Rare deleterious alleles more likely to combine in homozygotes
(expression of homozygous recessives

Question 21

If you self, a greater proportion of your offspring are ___________than the
proportion from individuals that outcross
Nonrandom mating changes _______ frequencies
* Depending on the amount of genetic variation, this could produce_______ ___________ at many loci in your offspring
Selection acts on ____________
* If a significant proportion of mutations are _________, these will be expressed…
A greater proportion of your offspring will have _____ _______ than expected with
______ mating

Answer 21

If you self, a greater proportion of your offspring are homozygous than the
proportion from individuals that outcross
Non random mating changes genotype frequencies
* Depending on the amount of genetic variation, this could produce homozygous
recessives at many loci in your offspring
Selection acts on phenotypes
* If a significant proportion of mutations are deleterious, these will be expressed…
A greater proportion of your offspring will have lower fitness than expected with
random mating

Question 22

Natural selection

Answer 22

a predictable change in the frequency distribution of a trait between the parental and
offspring generations as a result of three conditions:
1)Individuals vary
2) Survival and reproduction are not random
3) Variation is passed on to offspring (Inheritance)
1

Question 23

Evolution in response to natural selection is ________ when these conditions are met
* Results in Differential propagation of different genotypes
* Specific features of the environment can generate natural selection on a trait
What are its effects?
* ________ of one allele/_____ of genetic variation
* Maintenance of _______ _______

Answer 23

Evolution in response to natural selection is inevitable when these conditions are met
* Results in Differential propagation of different genotypes
* Specific features of the environment can generate natural selection on a trait
What are its effects?
* Fixation of one allele/loss of genetic variation
* Maintenance of genetic variation

Question 24

* Analyzing change in frequency of traits in a population: * Three patterns emerge:

Answer 24

– directional selection – stabilizing selection (and balancing selection) – disruptive selection

Question 25

directional selection: stabilizing selection disruptive selection

Answer 25

directional Selection: Individuals of one extreme phenotype favoured * Stabilizing Selection: Individuals with intermediate phenotype favoured, extreme phenotypes selected against. * Disruptive Selection: Both extreme phenotypes favoured; intermediate phenotypes selected against

Question 26

Modes of selection: no selection When condition 2 does not hold, selection cannot proceed, what the condition 2?

Answer 26

2 conditions= (survival and reproduction are not random)

Question 27

modes of selection: directional Evolution of the trait mean (at least). Occurs when...

Answer 27

Evolution of the trait mean (at least). Occurs when fitness varies positively or negatively with “trait” size

Question 28

Stabilizing selection

Answer 28

Variance decreases between generations, but the trait mean does not change -Average individuals have higher fitness than extreme individual

Question 29

Stabilizing Selection: - ____________ advantage -Single amino acid substitution leads to.... -________ allele A(normal), S(sickle)

Answer 29

*Heterozygote advantage *Example: Sickle cell anemia and malaria *Single amino acid substitution leads to crystallization of hemoglobin at low oxygen concentrations *Co-dominant alleles-BUT I THOUGHT THIS WOULD BE INCPMPLETE DOM BASED ON THE OG DEFITION HE GAVE US????? A (normal), S (sickle) Heterozygotes AS have mild condition, homozygote SS often don’t surviv

Question 30

-Malaria caused by ... * Individuals “normal” (AA) at the sickle cell locus get ______ ____ ______, heterozygotes ____ ____, blood cells sickle ......

Answer 30

malaria caused by Plasmodium falciparum (a protist) that also infects red blood cells * Individuals “normal” (AA) at the sickle cell locus get very bad malaria, heterozygotes less bad, blood cells sickle slowing population growth of protist

Question 31

Disruptive selection

Answer 31

Both extreme phenotypes favoured; intermediate phenotypes selected against Average individuals have lower fitness than extreme individuals

Question 32

Drift and Selection : Natural selection is more powerful in large populations because

Answer 32

Drift weaker in large populations Small advantages in fitness can lead to large changes over the long term

Question 32

- Viability selection: * Fecundity selection:

Answer 32

- Viability selection: differences in survival * Fecundity selection: differences in reproductive succes

Question 33

Gametes- males - females-

Answer 33

Gametes!! * Males produce abundant, energetically cheap, and more motile sperm * Females produce few, energetically expensive, and less motile egg

Question 34

sexual monomorphism- sexual dimorphism-

Question 35

The Evolution of Sexual Dimorphis, reproductive success = ____ + _____

Answer 35

reproductive success = fecundity + mating success

Question 36

The evolution of sexually dimorphism - natural selection : inevitable outcome when three conditions occur together; variation, fitness differences and inheritance. Fitness differences: involve at least one of mating ability, fertilizing ability, fertility and/ or survivorship Sexual selection broader than Darwin’s conception of natural selection: result of heritable differences in fertility and/or survival In contrast, Darwin considered selection that arose because of mating ability or fertilizing ability as a different process, sexual selectio

Answer 36

natural selection : inevitable outcome when three conditions occur together; variation, fitness differences and inheritance. Fitness differences: involve at least one of mating ability, fertilizing ability, fertility and/ or survivorship Sexual selection broader than Darwin’s conception of natural selection: result of heritable differences in fertility and/or survival In contrast, Darwin considered selection that arose because of mating ability or fertilizing ability as a different process, sexual selection

Question 37

is sexual selection different

Answer 37

Darwin realized many of the traits produced by sexual selection often diminish survival. The modern perspective actually incorporates sexual selection as part of natural selection, recognizing that the process does not differ, but the outcomes may

Question 38

what are 2 types of sexual selection

Answer 38

Sexual selection results from either or both of two components of mating: 1) Intrasexual selection: fitness differences resulting from differing abilities of members of the same sex to compete for mating opportunities (i.e. male-male competition) 2) Intersexual selection: fitness differences resulting from preferential mating between specific males and females (i.e., mate choice)

Question 38

What are differences in parental investment? What is reproductive success?

Answer 38

Differences in parental investment – gamete production – eggs are expensive, sperm is cheap – in any species, more sperm than eggs are produced – parental care – cost of bearing (pregnancy) & raising offspring – usually greater in females, but exceptions exist * Reproductive Success: Females are limited by resources, males are limited by access to females (usually