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Vestigial
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appendix
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Cuvier
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fossils, catastrophism
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Intersexual Selection
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Mate selection
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sympatric speciation
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not separated
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Genetic Drift
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gene pool changes
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Purines/Pyrimidines
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Purines: adenine and guanine
Pyrimidines: cytosine and thymine
-these are nitrogenous bases
-DNA also consists of a phosphate group and a 5-carbon sugar
-DNA molecule has sugar-phosphate-sugar-phosphate backbone
transition: (ts) purine purine or pyrimidine pyrimidine (A<>G or C<>T)
transversion: (tv) purine pyrimidine (A<>C or G<>T)
-transitions more common, due to size of nitrogenous base (ie. single or double ring)
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Cambrian Explosion
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550MAexplosion of lifeforms, diversity;all of living phyla become present at this time
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homologous
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ore specifically, in evolutionary biology, homology has come to mean any similarity between characters that is due to their shared ancestry. There are examples in different branches of biology. Anatomical structures that perform the same function in different biological species and evolved from the same structure in some ancestor species are homologous.
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Stabilizing selection
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Selection favors intermediate phenotypes
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intrinsic
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genetic mechanisms independent of environment
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Vestigial Structure
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reduced or functionless anatomicalfeatures that are fully developed in other species
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appendix
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probable: digestive or immune systemwhy: wastes energy
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permineralization
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where original biological tissue is replaced by exogenous elements (ex: petrified wood)
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Gene Shuffling
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recombination of genes during meiosis
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Reproductive isolation
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small dog vs big dog
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disruptive selection
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middle individuals are selected against so individuals on each extreme do better. if the next generation produces offspring randomly, it'll go back to its original curve
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casts
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formed by minerals deposited in molds
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homologous structures
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-same anatomical features and evolutionary origins-similar origin but not in function
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clade
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group in phylogenetic tree that contains all ancestors and descendants
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Fitness
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An organism's genetic contribution to the next generation (number of fertile offspring produced)
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Strength of Sexual Selection
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Mating systems:
-monogamy
-polygyny (male promiscuity)
-polyandry (female promiscuity)
**sexual selection is most intense when there are many mates (promiscuity) and less intense when monogame (everyone gets a mate)
In rough skinned newt, there is no parental care, yet females astill seem to be choosy.
In pipfish, paternal care is exemplified, and a reversal of bateman's rule is observed
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evolution
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change i gene frequency between generations in a population
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microhabitat specificity
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Insects speciating because they take over different plants; in same habitat, but separate microhabitats--
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Diploid Sporophyte
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-certain cells undergo meiosis -> produce lots of haploid spores- spores are spread by wind-> why they land in a good spot they grow into haploid gametophytes
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Reproductive barrier that occurs when 2 species mate but fail to produce fertile hybrids is:
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postzygotic barrier
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Diversifying Selection
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Individuals on both extremes are favored
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What is Va?
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Additive variance is essentially genetic variance.
It represents variability of a trait due to the effects of several genes/loci
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Convergence + example
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independent evolution of similar characterin two or more lineages. Example = Sharks and Whales
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Which of the following statements is an inference of natural selection?a. Habitats do not generally have unlimited resources.b. An individual organism undergoes evolution over the course of its lifetime.c. Some of the variation that exists among individua
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E
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Theory
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Concept that has been tested and confirmed in many different ways and can be used by scientists to make predictions about the natural world
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kin selection
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promotes aid to descendant and non-descendant kin
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Kin selection is selection at the level of the species (T or F)
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False
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What is gradualism?
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Species gradually changing over time
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special creation
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Christian belief that God created everything; everything that he created is the same as it is today;
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species selection
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A theory maintaining that species living the longest and generating the greatest number of species determine the direction of major evolutionary trends.
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mechanisms of evolution
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mutation, genetic drift, natural selection
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Did birds, reptiles, fish or worms evolve most recently
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birds
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punctuated equilibrium
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a hypothesis holding that the evolution of species proceeds in a characteristic pattern of relative stability for long periods of time interspersed with much shorter periods during which many species become extinct and new species emerge.
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gradualism
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a model of evolution in which gradual change over a long period of time leads to biological diversity
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gamete
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female and male gamete do not attract each other and do not fertilize
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Three things paleozoic
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begins and ends with invertebrate radiation and extinction, movement onto land, appearance of vertebrates
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Molecular biology
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Animals with similar amino acids are similar in common ancecstors
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A certain species of land snail exists as either a cream color or a solid brown color. Intermediate individuals are relatively rare. Which of the following terms best describes this?a. disruptive selectionb. directional selectionc. stabilizing selectiond.
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A
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adaptation
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a process that enables an organism to become more fit
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Formation of protobionts
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Protobiont: bubbles that had cell-like capacities-boundary!Structurally like living cells-polymers inside-enzymatic action-can replicate!
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ecological opportunity
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organism takes advantage of the lack of competitions in an environment and acclimates - may deviate enough to become own species.
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early origins of hominids
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-homo originated ~4-5MYA
-H. sapiens ~500kya
African rain forests started to dry up 5-6MYA
-small population east of Great Rift Valley isolated
-occurpid grassland/savannah
-diverged in allopatry from lineage leading to chimpanzees
Hominid Lineages
-evolutionary relationship uncertain
-multiple overlapping lineages
-We know the species tree for gorilla/chimp/human, yet the gene tree does not alawys match
-however, 11/14 loci showed chimp and human to be closest (which is true)
** multiple groups of homo existed!!! and other linages
Based on cranial and dental traits of humans, apeas, and fossil hominids
Multiple lineages present at same time
Phylogeny based on characters questionable, timing of fossils is NOT
RECENT HOMINIDS
H. heidelbergensis
H. neanderthalensis (Europe)
H. erectus (Asia)
H. ergaster (Africa)
aleoanthropologists split on taxonomic status
-cannot know origins
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What is evidence of macro evolution?
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Fossil RecordHomologous StructuresVestigial StructuresHomologous EmbryosHomologous Molecules
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typological species concept
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developed by Linnaeus (1735) members in a group must conform to the group if they want to be included; classical
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sexual dimorphism
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special case of polymorphism based on the distinction between the secondary sex characteristics of males and females.
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Alfred Russel Wallace
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came up with natural selection independently of Darwin
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divergent evolution
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the pattern of evolution in which species that once were similar to an ancestrial species diverge or grow apart.
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Law of independent assortment
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The mendelian principle that genes controlling different traits are inherited independently of one another.
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Definition Of
Convergent Evolution
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A kind of evolution wherein organisms evolve structures that have similar (ANALOGOUS) structures or functions in spite of their evolutionary ancestors being very dissimilar or unrelated.
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Frequency Dependent Selection
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Decline in the reproductive success of a morph resulting from the morph's phenotype becoming too common
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how does genetic drift occur?
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chance matings between individuals with similar genotypes
random differential reproductive success among individuals w/in a popn
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Difficulties in tree building5)
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Gene trees don't equal species trees-An accurately estimated gene tree may imply the wrong species phylogeny
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balancing selection and coalescence
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under neutrality, one can predict average time to coalescence of two randomly chosen alleles
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Parent-Offspring Conflict
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siblicide- in birds and mammals it is common for siblings to kill each other while parents seemingly do nothing
-blue-footed booby
-facultative siblicide
-smaller sibling is killed only when food is scarce
-extra reproductive value
black eagle
obligate siblicide
-smaller sibling is always killed regardless of food availability
-insurance reproductive value (what if one egg doesn't work?)
Can parents reduce siblicide?
-when above birds crossed, and parents and offspring all unrelated, masked booby (obligate siblicide) encourage siblicide by holdig back food
-parents and chicks responsible
-in facultative siblicide, an increase is observed.
PLAYING FAVOURITES-unequal distribution of food
-are there advantages to siblicide? (surviving offspring benefits)
-removing badgenes
PARENT-OFFSPRING CONFLICT-ill isbling gains future offspring for one offpspring
-parent net loss of future descendents
-tradeoff
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What is an ecotype?
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Where one particular phenotype is found
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Experimental Study of Adaptation
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Threat display by tephritid fly appears similar tot he jumping spider
Hypotheses:
1)flies to no mimic jumping spider
2)flies mimic spider to deter non-spider predators
3)flies mimic spider to deter predation by spiders
Predictions:
1) no mimicry... all predators will attack fly
2)mimicry deters other predators ... banded wings will deter other predators only
3)mimicry will deter spiders
Can reject 1 and 2. Fail to reject 3.
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Sexual reproduction
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Another way of adding variation to a population because offspring are a mixture of the DNA of two parents.
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galapagos islands
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an archipelago on the equator in the Pacific, ab. 600 mi. (965 km) W of and belonging to Ecuador: many unique species of animal life. 4058; 3029 sq. mi. (7845 sq. km).
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Macro evolution includes (name 4)?
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1. mass extinctions2. origin of species3. adaptive explosions4. the evolution of biological novelties
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why are human gene mutations so rare?
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we have proofreading capabilities.
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Natural Selection & Sympatric Speciation
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Rhagoletis fly dependent on hawthorn or apple to mate
-appls introduced to North America <300 years ago
-flies court, mate and lay eggs on/in fruit
Host Shifts
phytophagous insect Rhagoletis
-1864 found in aples
-2 host races
How did the two host races originate from a single host population?
1)natural selection through preference for food source then 2 genetically distinct groups of flies
2)flies use apples or hawthorns depending on availability then 1 population of flies
both apples and hawthorns are now found in similar areas
-examined allele frequencies at six protein loci in the two host races
-significantly different... how did this originate?
1)preference for host plant heritable
-both sexes have preference for natal host
2)mating occurs on host plant - non-random mating
-6% matings between host racs (HUGE in terms of gene flow)
-high enough to homogenize populations
-?strong natural selection?
Hawthorne fruit matures 3-4 weeks after apples and larvae experience cool period before pupating
Are there alleles that favour cool period?
-hawthorne pupae exposed to warm-cool-war cycle to mimic change of seasons
-examined adults that emerged (surviving adults only)
Changes occurred in a single generation
-hot and cold alleles were present in the population before the apple plant was introduced to North America
read about this... Speciation, page 5.
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Mechanisms of ways populations evolve
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Mutations - driven by genetic variation
Natural Selection
Genetic Drift (sampling error)
Migration
Genetic Recombination
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Population genetics
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the gene pool of all the genes in a species
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What is used to represent the total population? total sample size?
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N n
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Major Eons of Earth's History
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a billion yrsHadean -> Archaen -> Proterozoic -> Phanerozoic
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What was Darwin's first major publication?
Who did he have to share credit with?
When was it published?
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The Voyage of the Beagle.
Captain Fitzroy (and egotist) required that his name be placed on the publication as well.
1839
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what is a multi-gene family?
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-cluster of tightly linked genes on chromosome that originated from single ancestral gene by process of gene duplication.-duplicated copies have acquired new functions
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Who contributed to D's finch work? What did he contribute?
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John Gould.
He drew them and described their species, that they were all the same species essentially with really different beaks specialized to their island.
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Gremlin in chicken vs duck feet
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-in duck feet-suppresses a gene that degenerates web feet-web feet ducks, not claw feet chickens-Embryos of duck and chicken had web feet-Lack of gremlin expression allows a gene to degenerate webs, causing only toes
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What are the 3 mating selections?
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Monogamy - one mate per mating season/life spanPolygamy - one male, many femalesPolyandry - one female, multiple males
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Key ideas in how evolutionary thinking developed
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- deep time- rudimentary understanding of biological inheritance- basic understanding of ecology- scientific revolution (astronomy, geology, physics, math, chem, bio)-discover or new faunas- extinction- microscope
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Can we use phenotype to determine genotype?
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-only when single gene
-DNA is more powerful
CF (cystic fibrosis)
-CFTR gene: cell surface protein expressed in lung membranes
-one function is to ingest or destroy Pseudomonas
-individuals with mutation in CFTR have CF
-out of 15000 patients, 500 different mutations
-all same phenotype
-all have CF
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3 explanations how a trait isn't an adaptation
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-trait evolved by random genetic drift- trait evolved because it was correlated with another that was the direct target of selection- evolved by sexual selection
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What is the graph of directional selection?
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One end of the curve has higher fitness that the rest.
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why's it necessary to "correct" for phylogenetic history ?
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b/c the data may not be independent of one another. This means that the trait may be found in a group of species because it was inherited from a common ancestor rather than having evolved independently in each group
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