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69 Cards in this Set

  • Front
  • Back
Direct benefit
Hypothesis as to why some females prefer particular traits
1. Provision of resources through males to females: nuptial gifts
example: dung beetles are attracted to bigger dung balls
example: praying mantises get resources by eating the male and given to young
2. Territory
Red-headed weaber birds impress females with nests and red collared widow birds. big brains connection

3. Avoidance of disease
Good genes
Hypothesis as to why some females prefer particular traits
"handicap princible" - Zahavi says sexual ornaments are costly. Therefore exaggerated sexual traits must indicate that the male carrying those must be in good shape and carry good genes. Under this hypothesis, sexual ornaments are advertisements for good genes.
It does not say " if i am handicap and i survive, i must be intrinsically stronger" ....

It means sexual attractive quality must come at the expense of something else-- so sexual ornaments must signify good genes for survival.

parasite resistance
Sensory Bias

example
Hypothesis as to why some females prefer particular traits
Certain traits may be intrinsically stimulating and evoke a greater response simply because of the organization of the sensory nervous system.
Priapella fish ( no sword fish) .
Females of the species had an intrinsic preference for males of their own species that had a fake sword attached to the tail due to a pre-existing sense.
Runaway Selection
Simply there is a pairing between the preferences in the female and the traits of the male.
Even in the absence of resources, good genes or sensory bias can sexually select and give rise to weird adaptations.

Runaway selection can occur when the genes that give a male a certain phenotypic trait are linked to the genes that make females prefere these traits
4 different hypothesis on sexual selection
1. Direct benefits
2. Good Genes
3. Sensory Bias
4. Runaway Selection
Male Scroprian flie
Male provides salivary secretion to get female to mate with him.
The longer the excretions, the increased copulation duraiton
Experiment: Females mated and half of them provided extra secretions artividially controleld form mlaes. Bascially the more of the liquid the more eggs she provided
Why did red-collared window bird males have long tales?

principle
1. 120 male birds were caught: 60 had their tails trimmed, 60 were left untreated

The longer tails are more attractive to females because tail length correlates to with good genes (resistance to parasites)
Handicap principle?
Red-comb signaling according to Hamilton Zuk Hypothesis
when a bird gets sick, the comb gets pale. So a red comb shows that this bird is carying genes that makes it more resistance to infection.

" good genes"
Hamilton zuk 3 assumptions
1. parasites reduce host fitness
2. co-evolution between the host and the parasite so that the host evolves genes that make them resistiant to
3. hosts with higher resistance are in better health and able to show better sexual displays
How to female peacocks pick a male?
When the females spot a nice mate with the most eye spots aggregated in " leeks".
Males with more eyes will have more mating success.
When added with LPS- the brids with more eyes were more able to fight off of the LPS infection.

Conclusion: Found that more eyespots indicated genes that could over come LPS infection.
Barn Swallows and Moller
Direct Fitness consequences
What hypothesis does this prove?
Good genes
1. shortened tail and glued it back on ( to have it maintain the deep V shape)
2. control1: Cut the bird without shortening
3. Control 2: didn't touch the brid
4. Glued on longer feathers

Shorter tails: took a long time find a mate,
Artifically elonged tails: took an even shorter time to find a mate than the controls and even MATED TWICE!

Measured Fledge: artifical elongated tail had a better mating success.
Why are males with longer tails more attractive to females in Barn Swallows. What hypothesis?
Good genes.
Moller followed up with another exeriment to test Hamilton and Zuk. Genetic coding for mite resistance correlating to long tail length.

Found there is a biological connection between Mites on Paternal father and offspring. Also., the longer the tail , the fewer the mites there will be.

There is a correlation between the number of mites on the male parent and the number of mits on the offspring in Nest.

But. There is no relationship between the number of mites on fostering offspring in own nest
Why would a female prapella fish prefer a species with a sword tail?
1. they used to have a common ancestor that that had a sword.
2. but no, because the sword developed after the common ancestors
3. Preference prexists the evolution of long swords- due to a sensory perception
Why do bower birds prefer blue?
some studdies suggest that sensory bias also play a role in bower birds, where preference for certain colors may arise because of their association with ripe fruit. other species have a similar blue excitiory-- wavelength.
Eyestalkes of flies
1. daughter's preferences match the sun's trait depending on if he had a short or long stalk.
2. example of RUNAWAY selection
linkage between daughter and son will drive greater longer eyestalks which drives greater strong preferences.
What form of sexual selection causes speciation and why?
Runaway slection.

Run away selection causes dramatc increase in traits and FAST.
What is true of the sexual preference and fitness of red-bowered birds?
Longer tail males had more NESTS in their territory: It seemed that control males with long tales could attract more females to the long tail. BUT the short tailed lost less weight than the long tailed contorl.
What are the 4 attributes of the Scala Naturae
Embraces the whole of nature
continuous in structure
men are at the mid-point of perfection
Women are somwhere between men and naimals.
Where does the scala naturae develop from and when does it reach its zenith?
The scala naturae rooted in aristotle but reach its zenith during the enlightment.
Alexandre Pope followed the Scala naturae in ESsay on Man
Mark Dion**
Artist who depicted the scala naturae as an art piece

secular- doesn't believe in mystics
3 ways the scala naturae- perfection of man began to be questioned
1. discoer of fossils
2. geology as a science
3. the discovery of non european race " primitive races
What was the first example of the evolutionary tree?
Chain of Being: still only a results of PROGRESSIVE DEVELOPMENT.
Lamaraks 1809 first example worms and insects developed to mollusks- the fish reptiles-- amphibious mamals such as whales, hoofed mammals and mammals
La Marche de la Nature
Jean Baptiste Lamark(19744-1829) proposed the Parade of nature as a transformed scala to an escalator.
Felt need
A mechanisstic and progressive theory leading to steady improvements through the inheritance of ACQUIRED characteristics.

Because usesful organs would be used, exercised, and more fully developed than other organs.
Darwins Birthday and length of voayge
1809-1882 and a beagle voyage that lasted five years from 1831-1836
What influenced Darwins thinking on the beagle?
Geology. Darwin's mentor Henslow gave him the PRINCIPLES OF GEOLOGY by Charles Lyelll
Uniformitarianism and Gradualism
Lyell's ideas in Principles of Geology which were formulated by hutton
Henslow
Hutton
Lyell
Lamark
Malthus:
Wallace
Hooker
Henslow- Darwin's mentor on the Beagle
Hutton- originally formed philosophies of uniformitarisnism and gradualism
Lyell: wrote Principles of Geology
Lamark: marche de la nature, felt need.
Malthus: Essay on population
Wallace: research from Malay Archipelago
Hooker: publishes wallace and Darwin's essays simultaneously
What was darwins first great insight stimulated by?
Descent with Modification developed after studying finches in the Galapagos island.
First Principal of Theory of Evolution by Natural Selection
Variation. There occurs, within every species, natural variations among individuals of that species and these variations arise strictly by chance
Second Princ of Theory of evolution by NS
Heritability Variations are passed on to offspring.
3rd princ. of theory of evolution by NS
Among these heritable variations some variations will lead to a great propensity for reproduction and survival, hence leading to an increase in the appearance of this favored trait.
Polymorphism
Variation among humans due polymorphisms, so this variation is due to both genetic and environmental factors.

Human hight- and the Heliconius butterfly wing pattern
Cryptic Variation
Recessive lethal alleles like Cystic Fibrosis, tay-sachs disease, sickle-cell anemia and barchydactyly
Why aren't lethal alleles purged from the population in cryptic variation?
j
Clinical Variation and Ecotypes -- is it due to genetic or environmental differences?
ex. variation in plant height along an altitudinal gradient.
Is molecular variation under natural selection
Enzymes polymorphism's, alloenzympes Sequence variations like SNPs, microsaellite sequences and amplified fragment length polymorphisms (aflps)
What was Darwin's biggest problem?
What the mechanism of inheritance was. If blending inheritance is true ( that was the only proposed mechanism) then why would the net effect of mating be loss of variation.
I.Red and white seems to yields pink... not more red and white...
HBD Kettlewell
First person to do experimental evolution in natural populations.

1. Pinned moths to trees in different habitats and observer predation rates on each type by birds
2. released mixed populations of moths in different habitats and examined recapture frequencies
What principle do the Peppered moth show?
It showed how natural selection can maintain variation of polymporhism through differential predation.
What are the recessive and dominate types of the Peppered moth?
The dominant type: Carboneria found in polluted areas to blend into darker/ poluted tree bark

The Recessive: Typcia is on cyptic normal trees
What selective force accounts for the differentiation between banded land snail?
Slective predation from the Song thrush bird effects the color morphs of the banded land snail in different habitats.

Snails that live in the dark woody areas have dark bands.

Snail that live in the grassy habitats have yellow bands.
What do various pelage colors in the oldfield mouse signify?
There is a selective advantage of cryptic coloration. There are less predator attacks if the mouse blends in with its habitat.
Does Pelage Color follow Mendelian inheritance?
Yes. George mendel says that particular interitance maintains variation.. mixing a pink rose with a pink rose will not lead to 4 pink roses, but 2 pink roses and a red and white rose
What is true under the Hardy-Weinberg Law?
Under random assortment of gametes ( no natural selection), allele distribution and variation is maintained from generation to generation at the same fequency
What does HW assume?
No Migration
No Mutations
Large enough population
Random mating
No gene linkage ( linkage equilibrium)

akak. no selection.
What is the significance of HW if it rarely occurs?
HW forms the null hypothesis for evolutionary dynamics- and will tell us if one of the assumptions have been violated if the population genotype significantly differs from HW Values
p=
frequency of A1 Alle
p^2+ .5(2pq)
q=
frequency of A2 allele
q^2 + .5(2pq)
p^2 and q^2=
Initial genotype frequencies


P^2 is therefor the frequency of A1A1 genoytypes

(NOT ALLELE FREQUENCIES)
How do we calculate the genotype frequencies after selection?
1. The frequency of that genotype (before selection), p^2
2. The genotypes fitness
W
3. the average fitness of the population
Wavg
(p^2 * W11) / W avg
Calculate the average probability of survival in the population at hand
Use normal hardy Weinberg BUT must include the genotype's fitness
w= p^2W11 + 2PQ12 + q^2 w22
w=
relative fitness of the genotype!
The viability of that genotype/ the highest viability
How do we calculate frequency of an allele?
It will be determined by the frequency of individuals homozygous for that allele (and their fitnesses), the frequency of individuals heterozygous with that allele (and their fitnesses), and the average fitness of the population.
How does selection effect allele frequency?
allele frequency changes due to selection and are a function of initial allele frequencies, population mean fitness, and mean fitness changes as a result of allele frequencies. ..

So we can therefore predict the change in the frequency of an allelechange that is a result of selection
S1
the selection coefficient AGAINST the A1, A1 gentotype

When s is big
natural selection is a force that ______ individuals from a population. Explain how this effects the strength of selection of a particular phenotype.
1. we view natural selection as force that REMOVES individuals from a opulation
Therefore- we measure the strength compared to the maximum fitness, which we scale to 1.

The fitness of the A2A2 would= 1- S2.. and s2 s the selection coefficient against A2 genotype
h=
heterozygous effect, or the degree of allelic expression of the heterozygotes...
H shows us which which allele is dominant in the heterozygote, which will allow us to calculate the degree to which A2 is expressed in the population
When h=1
heterozygotes express ALL of the A2 allele and it is completely dominant
when h=0
heterozygotes express NO A2 allele and A1 is dominant
what is the pattern of selection for a heterozygote advantage in order to maximize population mean fitness.
A1A1= 1-s1
A1A2=1
A2A2= 1-S2
What is the pattern of selection for homozygote advantage in order to mazimaize population mean fitness?
A1A1= 1+s1
A1A2= 1
A2A2=1+S2
Formula for heterozygote advantage
w= 1- p^2- P^2s1- q2s^2
Equilibrium value for A2
frequency of the A2 at which the population mean fitness is maximized.
Q HAT
q hat for heterozygotes
qˆ =s1/
(s1+  s2)

Which is saying that the equilibrium value for A2 is determined by the strenglth of selection against the Homozygotes: A1A1 ( se) relative to the sum of seletion against A1A1 (sS1) and A2A2 (s2)
How will the A1 and A2 stablize in a heterozygote advantaged population.
They will not fix because A2 will reach a stable equilibrium which maximizes the frequency of heterozygotes
When would theA1 and A2 alleles be maintained at the same equilibrium?
I'm not sure-

i think when q hat and p hat are equal.. when S1=s2
What is the difference between q and qhat?
q= value of q in H-W conditions occurs when there is no evolutionary forces

Q hat=equilibrium value of q
however in a heterozygot advantage shows that delta q stops changing because population mean fitness has been maximized- and if theq has any change in frequency then there will a reduction in population mean fitness.
Viability
observed/expected