Evolution Exam Flashcards

Terms Definitions
ancestral character
essential for evolution
Natural Selection
Environmental Pressure.
Eldredge and Gould
Punctuated Equilibria
continuous trait
height, many possibilities
1. Charles Darwin (1809-1882)
2. Alfred Wallace (1823-1913)
distinguished species, doesn't help draw evolutionary connections
monophyletic group (all entities descended from the same common ancestor)
Devonian Extinction
-330mya-mainly affected marine taxa-newly emerged terrestrial fauna were unaffected-unknown cause: possible meteor impact or glaciation
Social behaviour consists of..
-reciprocal altruism
-parent-offspring conflict
Georges Cuvier, no evolution, extinctions followed by replacement of species from other regions. Species too complicated to evolve
Changes in allele frequencies in populations.
Early classification
Kingdom Monera, Protista, Fungi, Plant, Animal
Geographic Isolation
Natural barriers isolate populations creating different species
Darwin's Book
On the Origin of Species
Members of two different species possess a similar-looking structure that they use in a similar fashion to perform the same function. Which information would best help distinguish between an explanation based on homology versus one based on convergent evo
Group of organisms that can potentially interbreed among one another.
mechanisms whereby the evolution of cooperative or altruistic behavior may be favored by probability of future mutual interactions - donor and recipient change roles over time
Allopatric Speciation
Populations phsycially isolated (ie rivers or mountains)
-geographic isolation precedes ivergence
-reproductive isolation only observed on secondary contact
-through dispersal or vicariance
If dispersal, predict:
-closely related species found on adjacent islands
-branching events correspond to order in which islands formed,
-Isthum of Panama rose ~3MYA
-did this cause gene flow to stop?
-examined 7 pairs of species.. found 3 cryptic spp
-why was the timing of the split not the same for all species????????
Shallow water spp can move until barrier complete
-deep sea spp split first
18th century French philosopher and naturalist; had the idea of spontaneous generation
When a species disappears and ultimately dies out
a structure or behavior that contribures to the survival of an organism in a particular environment is called an
A series of beneficial adjustments to the environments.
two or more populatons interact so closely that they evolve together
Parapatric Speciation
Kinda like allopatric speciation, but two pop'ns remain connected over a narrow contact zone.
when species diverge and turn into diffetn species
Define phenotype.
all measurable traits where variation may affect survival and reproductive process
results from genotype and environmental interactions
Hutton & Lyell
gradual geological change and uniformitarianism
If two modern organisms are distantly related in an evolutionary sense, then one should expect thata. they shared a common ancestor relatively recently.b. they should share fewer homologous structures than two more closely related organisms.c. they should
a population of organisms that breed together and share a common gene pool; they are able to produce fertile offspringd
Sympatric Speciation4 mechanisms
Natural selection overwhelms gene flow1)Spatial isolation: microenvironment within an area2)Temporal: some decide to wake at night, others at day3)Behavioral: Just decide not to interact4)Polyploidy: instant speciation within 1 generation
Cystic Fibrosis
CFTR cell surface protein
-ingest and destroy Pseudomonas
CF alleles 0.02 Europeans (2%.. very high)
-infertile... alleles cannot be passed on (s=1)
-predicted mutation rate is 0.004), actual is 25 fold lower
-so what is keeping frequency of disease causing alleles so high?????
*confers resistance to somthing else!!
Typhoid fever! (doesn't infect cell lining, but intestinal lining)
-are CF heterozygotes resistant?
-bacteria infect cell via gut lining
 -perhaps using CFTR protein?
-copy number
Looked at deltaF508 (1bp deletion)
-maybe CFTR gene allows port of entry?
-most common within CFTR gene
-many different mutations cause CF
-found heterozygote advantage!! (in mice)
-86% decrease in infection from wildtype to heterozygote (+/deltaF508)
-wildtype has extremely high rate of infection
-found very strong correlation in humans between number of typhoid cases and %mutant alleles that are deltaF508
vestigial organs
reduced forms of fully functional organs in other organisms
Embryological Structures
Early in development all vertebrate embryos are similar; shows that new genetic instructions have been layered on top of old ones
Evolutionary change in the timing or rate of an organism’s development.
Genetic Drift
Random change in allelic frequencies in a population
structures in different species that have the same evolutionary origin
homologous structures
to adjust to make suitable to conditions
parallel evolution
Two related species that have made similar evolutionary adaptations after their divergence from a common ancestor
geographic barriers
physically separate species - if they experience different selective pressures they may evolve into new species
If a species is found in several colors, what is responsible?
The Origin of Species/ sat for 8 years
Theory of Natural Selection
-Proposed by Charles Darwin-"Survival of the Fittest": those w/ advantageous variations are more "fit", "fit" genes get passed to next generation.-Organisms w/ less variation are more endangered-Natural selection results in inherited characteristics of a population, which increase a species fitness over time
if it has independently evolved 2 or more times and so does not have an unique origin
Balancing Polymorphism: Heterozygote Advantage
Heterozygote advantage is creating more variation, reducing the risk of matching genes that have a disadvantage.
Selection for recessive
1, 1, 1+S (WAA, WAa, Waa)
requirements for NS?
1. trait variation among individuals within a population2. variation in fitness associated with variation in traits3. traits are heritable
What is exaptation?
Adaptations that are modified body parts(ex. wings -> arms)
What is Speciation?
Process by which new species form
when dramatic changes are followed by long periods of stability it is called
punctuated equilibrium
5 Deductions of Darwinism
1. Individuals with favourable traits have advantage
2. Traits are inherited and passed on to next generation
3. Environment determines which traits are favourable
4. Over geological time, successful variations accumulate so later generations may be distinct from ancestors
5. Geographical isolation may lead to new species
Fungi Mutualists - Lichen
– fungus & cyanobacterium or/and photosynthetic algae– Colonize harsh habitatsoBacteria and algae provide the energy, and fungus provides protection
Relative fitness
ability of an organism to survive and reproduce
background value
what's it used for
minimum value attained by genotype
used to determine Va. you start with the background value and then add the other variances at different loci.
ex. in beak length the minimal beak length is .25cm, then additional loci add on to that.
Which type of natural selection occurs when an intermediate phenotype is favored?
A. disruptive selection
B. directional selection
C. genetic drift selection
D. stabilizing selection
E. adaptive selection
D. stabilizing selection
Major milestones of the Cenozoic
*Radiation of mammalsAppearance of hominids
A sequence of random events in succession can change the frequency of an allele. This is called:
random genetic drift
Punctuated Equilibrium
Same for a long time, then massive change in a short time and then no change again
how many exons does the average human have?
8.8 exons
Helper T cells
-recognize and kill infected T cells- stimulate B cells to secrete antibodies- kill free virus particles- Supply of T cells is finite
What type of evidence of evolution is : bones in a bird's wing and a human's arm are similar in structure
homologous structure
Problems with the PSC
1) What characters to use?2) What level of divergence constitutes a species?3) How do you distinguish between gene trees and species trees?4) Does not address mechanism.
what is used to represent the mean?
Y or Y bar
The _______ is the total alleles of all the genes in all the members of a population.
A. genetic drift
B. gene flow
C. gene pool
D. gene migration
E. gene selection
C. gene pool
gene pool
sum total of all alleles at a loci within a popultaion or the genetic make up of the population
What is coevolution?
It is where 2 species evolve in response to one another.
dangerous side effects of anti-biotics
bacteria can grow stronger, bacteria becomes immune, and no sickness can be cured without stronger medicines
Breaking the assumption of H-W that there is no migration
Also define this term
This introduces gene flow: incorporation of alleles into a population from another population
This acts against genetic drift to homogenize the populations
note: Not all migrations lead to gene flow as an animal may migrate but fails to survive and add to the gene pool
Example: Dispersal of pollen grains and seeds
Fossils: what is it, biases associated with fossils
Preserved rock, imprint, bonesOnly hard structures were preserved; jelly bodies did not leave fossils
What is relative frequency?
The number of times that the allele occurs in the gene pool
Reasons for female choice or preference
direct benefits: females may benefit from increased nutrition, provisioning, or paternal care that increases their reproductive output or the quality of their offspring.
indirect benefits:
good genes hypothesis: genetically superior mates produce offspring with higher fitness
sexy son hypothesis: females mating with prefered fathers produce sons with higher mating success
compare the primitive earths atmosphere to ours today
it hadd no oxygen, took over billion yeears to accumulate oxygen
what did lamark believe in
-change can happen during the life of the species and that change can be inherited -the use or disuse of organs can be transmitted to offspring which makes it more useless/useful next generation
Who ultimately encouraged D to publish his works?
What did he do for a living?
Alfred Russel Wallace
He had traveled to SA and Malay and formed a similar evolutionary theory to D's. He sent D a manuscript and D recognized their eery similarities.
Wallace wa a museum propreiter. He was poor and humble.
what conditions necessary for natural selectino to overpower the homogenizing effect of gene flow?
-when the strength of selection (s) exceeds the rate of gene flow (m)
When Nm is low, what happens to RGD?
RGD often ends up genetically differentiating amon populations.
What did he tell us could prevent the over population of the world?
Famine,Disease and War.Darwin found that it also applied to plants and animals.
How did D become the ship's naturalist? What did he do as a naturalist?
The ship had a physician who played the role of a naturalist who collected things on the journey. Darwin did this too, quite well, and the physician got pissed an quit.
As the naturalist, D collected things and sent them to Henslow. He sent plants to Hedwick to study.
Where did D keep his theories on transmutation?
He kept them secretly in a notebook b/c it was so controversial.
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