Biol 103 - Week 8

Front 1

The selection response depends upon what two things? (Breeder equation)

Back 1

Response = heritability x strength of selection

Front 2

What are quantitative genetic characters?

Back 2

Traits underlain by many genes (blend in offspring)

Front 3

What trait in humans has high variability?

Back 3

Height

Front 4

Stable conditions cause greater or less heritability?

Back 4

Greater

Front 5

The Dutch Afrikaner population is an example of what genetic phenomenon?

Back 5

The founder effect

Front 6

What disease in particular had unusually high frequencies in the Dutch Afrikaner population when they moved to Holland?

Back 6

Huntington's

Front 7

Difference between founder and bottleneck effects?

Back 7

Founder = potentially new selection forces (new population, new location)

Bottleneck = resident population reduced

Front 8

Two examples of bottleneck effects?

Back 8

1. Prairie chicken

2. Elephant seal

Front 9

Chance n individuals are AA?

Back 9

(p^2)^n

Front 10

If there is high heritability, the mid-parent value will...

Back 10

Closely approximate the offspring value

Front 11

Genotype and phenotype relationship is ________ in the field?

Back 11

Weaker

Front 12

What happened to the Prairie Chicken?

Back 12

Significant habitat destruction caused population reduction. This caused a reduction in the % of eggs that hatched (poor health). Habitat restoration was unsuccessful in fixing this. Had to bring in prairie chickens from another population (increase genetic diversity).

Front 13

What is genetic load?

Back 13

The presence of unfavorable genetic material in the genes of a population

Front 14

What are the steps of the extinction vortex?

Back 14

1. Population size reduced

2. Inbreeding

3. Exposure of deleterious alleles

4. Reduced fitness (and back to 1)

Front 15

What is the a.a. change in sickle cell that makes it so harmful?

Back 15

Glutamic acid --> Valine

Front 16

Why do occurrences of malaria and sickle cell overlap?

Back 16

Sickle cell heterozygotes makes it more difficult for plasmodia to adhere to RBC, cannot negotiate liver

Front 17

The phenomenon where by heterozygotes for both sickle cell and Thalassemia are no longer resistant to malaria is known as...?

Back 17

Negative epistasis

Front 18

What are the consequences of there being multi-genotype infections of plasmodia?

Back 18

Plasmodia genotypes have to compete with one another to out-replicate. Therefore, must invest a significant amount of energy into asexual reproduction. This comes at the cost of sexual reproduction (transmission).

Front 19

What is Essentialism?

Back 19

The theory that species are created in their present form, are distinctfrom one another, and are unchanging. They have a set of attributes that are necessary to its identity and function.

Front 20

What is a morphospecies?

Back 20

Species determined by differences in phenotype/morphology.

Disadvantages: Convergent evolution confounds this, does not reflect genetic/historical differences, where to "draw the line"?

Front 21

What is a phylogenetic species?

Back 21

The concept of a species as an irreducible group whose members are descended from a common ancestor and who all possess a combination of certain defining, or derived, traits.

Disadvantages: No agreement on how far back to go/how much makes two species different.

Front 22

What is a biological species?

Back 22

A group of individuals who can breed together.

Disadvantages: Can't be tested in historical populations. What about: sterile offspring, partial viability, organisms who could breed together but choose not to?

Front 23

What is allopatry?

Back 23

Physical separation of two populations.

No gene flow.

Front 24

What is sympatry/parapatry?

Back 24

Sympatry: Two populations existing in the same geographic area.

Parapatry: Two populations existing immediately adjacent to one another (have a narrow contact zone).

Gene flow.

Front 25

What is the classic model for modern synthesis? Speed?

Back 25

-Divergence in allopatry (genetic differences accumulate)

-Post-zygotic isolation (reduced fitness of hybrids)

REINFORCEMENT

-Pre-zygotic isolation (avoidance of hybridization)

Slow

Front 26

What is the sexual selection/conflict model? Speed?

Back 26

-Divergence (changes in sexual traits)

-Pre-zygotic isolation (incompatible mating signals)

-Post-zygotic isolation (reduced fitness of hybrids)

Fast

Front 27

What is vicariance speciation?

Give an example.

Back 27

New species are formed from the division of original population into two or more populations (a particular form of allopatric speciation).

Example: Snapping shrimp. Species found on opposite sides more closely related than different species living together. This is an example of the classic model for modern synthesis.

Front 28

An example of the sexual selection/conflict model?

Back 28

Sky Island Spiders. Desertification has fragmented range leavingisolated populations living at high altitudes. Little naturally-selecteddivergence or drift, but very rapiddivergence in sexual signals (drumming patterns, ornamentation, etc.).

Front 29

What behaviour of prairie chickens contributes to their lack of population health?

Back 29

Prairie chickens "lek" - they gather in a communal area and compete with one another to entice females to mate with them. Usually, only a select few males will mate with the entire female population. This has consequences on genetic diversity because most offspring will be siblings/half-siblings. Increases the genetic load.

Front 30

What is the selection of sickle cell depending on the presence of malaria?

Back 30

Directional selection towards no sickle cell if malaria not present.

Stabilizing selection towards heterozygote if malaria present.

Front 31

Why is Wolbachia a possible solution to malaria?

Back 31

When Wolbachia infects a host, it prevents any other virus from infecting that same host. It has been suggested that through genetic engineering it could be given to mosquitoes, however there has been backlash over genetic engineering.

Front 32

Which two phenomena do the cichlids illustrate? What other comments?

Back 32

Adaptive radiation and sympatric speciation.

However there is some allopatry at play. Different fish like different habitats (bottom-dwellers, surface-dwellers, etc.). - habitat fragmentation. Pre-zygotic isolation happening first.

Front 33

What does volcano lake show?

Back 33

Clear sympatry

Front 34

Describe the maggot fly (Rhagoletis) story

Back 34

Maggot flies historically grew only on Hawthorn trees. When apple trees were introduced, some began to grow on apple trees. Rate of maturation began to change depending on what fruit they diapaused in. Hybrids would mature at an intermediate time and therefore die. This shows sympatric speciation and positive reinforcement.

Front 35

What would a graph of pre-zygotic isolation vs. genetic distance show for

a) allopatric species

b) sympatric species

Back 35

a) A linearly increasing graph

b) A bunch of points in the top left

Front 36

What are the four outcomes of a hybrid zone?

Back 36

1. Reduced fitness of hybrids. Positive reinforcement. Species remain separate, zone disappears.

2. Slightly lower fitness of hybrids. Zone remains.

3. Equal or superior fitness of hybrids. Two species will become one species again.

4. If the hybrid zone also has a different habitat, an "ecotone" occurs. If hybrids have higher fitness in this ecotone - formation of a third species.

Front 37

What is Haldane's rule?

Back 37

In interspecific crosses inwhich one sex of the hybrids is inviable or sterile, it isinvariably the heterogametic (XY) (sex-determining) sex.

Front 38

What do hybrid zones generate?

Back 38

Clines in allele frequency

Front 39

What are the two hypotheses to explain Haldane's rule?

Back 39

1. Dominance hypothesis. All X loci in males are dominant due to hemizygosity.

2. Faster X hypothesis. Genes on X may be undergoing stronger selection since they are expressed in a hemizygous state.

Front 40

What is an unreduced gamete?

Back 40

I.e. When a 2n organism produces a 2n gamete.

Front 41

Does triploidy work? (n + 2n)

Does tetraploidy work? (2n + 2n)

Back 41

Triploidy = no

Tetraploidy = yes

Front 42

What is autopolyploidy? (instant, 1 generation)

Back 42

Polyploidy (having more than two haploid sets of chromosomes) resulting from breeding within a species.

Front 43

What is allopolyploidy?

Back 43

Polyploidy resulting from interbreeding between two species.

Front 44

What does a tetraploid organism have to mate with in order for their offspring to be fertile?

Back 44

Another tetraploid

Front 45

What are African clawed frogs known for?

Back 45

Polyploidization events

Front 46

What types of organisms most commonly undergo polyploidization?

Back 46

Insects, fish, plants, reptiles