Biology and Evolution Flashcards

Terms Definitions
kettlewell
moths
chordate
generalized vertebrate
Biotic Factors (living)
PredatorsCompedatorsPerisites
Idealism
Plato, two worlds
Isolation Mechanisms
Reproductive IsolationBehavioral IsolationGeographic IsolationTemporal Isolation
HIV
ORIGIN
-65 million infected
-1/3 died
-uses macrophages and T cells to replicate
HIV1 most closely related to chimps
HIV2 to other monkeys
 
 
 
the VIRON
-diploid ssRNA genome
-surface proteins
-enzymes:
---reverse transcriptase (RNA to DNA)
---integrase (splice HIV DNA into host)
---protease (process HIV proteins)
 
-host has CD4 and co-receptor
 
HIV1
-three separate transfers (groups M,N,O)
-humans and chimps have 98% similar DNA, but only 2% divergence
-WITHIN subgroup M there is 20% divergence, and there is 35% divergence between subgroups M,N,O
-this is huge
 
AZT - a drug used early on
-replaces OH on DNA with N3
-stops reverse transcription (can't' add nucleotide)
-over time, AZT becomes ineffective
-virus adapts... resistence in patience to AZT increases over time
-they think that AZT is being stopped from being incorporated
 
CCR5
-co receptor
-mutant allele (delta32)
---32bp deletion
---resistant to HIV (HIV can't enter cell)
---9% Europeans contain allele...absent in Asians and Africans
---more frequent in N Europe due to selection and drift (gene was useful during Black Plague)
 
WHY CAN HIV MUTATE SO QUICKLY?
-generation time
-single stranded RNA- no fixing or proof reading
-surface proteins - selection
-population size
autapomorphy
apomorphy (derived characteristic) in only 1 species
symplesiomorphies
homologous similarties in organisms due to a shared distant ancestor
Sympatric Speciation example
apple fly maggot
extrinsic
genetic mechanisms dependent on environment - sticklebacks adapt to benthic and limnetic areas
Geographic isolation
continents, islands, rivers, mountains, roads
overpopulation
organism's population exceeds capacity of habitat
Mechanisms for extinction (maybe)
Sea-level changeIncreased aridityShifts in ocean currentsBolide impacts: impacts of extraterrestrial impacts that could disrupt planet and its ecological/physical systems.Massive volcanism on a global scaleMethane belch
vestigal structure
a structure with no function
Convergent Evolution
Similar adaptations different spicies Whale and fish
characters
traits used to show evolutionary relationships
Cattle breeders have improved the quality of meat over the years by which process?a. artificial selectionb. directional selectionc. stabilizing selectiond. A and Be. A and C
D
parallel evolution
development of similar though geographically separate adaptations
homoplasy
similarity in structure NOT inherited from a common ancestor
Homologous Structures
structures found in different organisms suggest that they have a common ancestry
Why bother with D?
1)Reconstruct Gene/Allele History
 
Gaucher disease
-mutation in GBA gene
-enlarged spleen, anemia, fragile bones
-1/19 Ashkenazi jews are carriers
---N370S allele, also found in other population (370th a.a., not unique))
---84GG allele (extra a.a. guanine), unique to Ashkenazim (want to trace history of this!)
 
-identified marker linked to GBA on chromosome 1
-D1S305: microsatellite
---allele with 8 repeats found in 59% individuals with 84GG compared with 24% GBA+
 
Origin Linkage?
-DRIFT!
-estimate time to most recent common ancestor (TMRCA) 1.3kya
-other disease-causing alleles in Ashkenazim population
---ie. Tay-Sachs, Fanconi anemia
-TMRCA: 3 groups... 400/1.5/3 kya
 
-dates broadly consistent with population history and series of founder effects
-left the middle east 2-3 kya
-arrived in central Europe 1-1.5 kya
-arrival in Lithuania (recently)
 

2) POSITIVE SELECTION
-favour advantageous mutation
-G6PD on X chromosome
---100s of alleles, most decrease enzyme's efficiency
---varying effects (severe.. hemolytic anemia which bursts RBC)..(allele 202A, possible malarial resistance)
-18% in 3 African populations
-230 males, 9 alleles, with 11 point mutations
 
**strong correlation b/w frequency of G6DP deficient males and malarial endemic regions
 
If G6PD-202A is under positive selection, what owuld the distribution look like?
-If mutation is neutral and on single locus, three possible fates
-over time... drift... linkage equilibrium with other loci
 
OTHER EXAMPLES OF RECENT POSITIVE SELECTION
-sperm motility and fertilization
-carbohydrate metabolism
-olfaction
-lactase
 
Population Mutation-drift Equilibrium:
-young, rare alleles: high linkage disequilibrium
-old,rare alleles: low linkage disequilibrium
-old, common alleles: low linkage disequilibirum
scientific name for stickleback
Gasterosteus aculeatus L.
coevolution
evolution involving a series of reciprocal changes in two or more noninterbreeding populations that have a close ecological relationship and act as agents of natural selection for each other, as the succession of adaptations of a predator for pursuing and
diversifying selection
a type of evolution that simultaneously favors at both extremes of the distribution
Fungi predators
- sticky substance on hyphae- constricting rings catch preyex: fungal rings contracts and catches nematodes
The smallest unit of evolution is what?
Population
Example of BottleNeck Effect
something getting killed indicriminately
 
(disasters,it is unpredicable)
 
 
mutation
alteration of a gene or chromosome (verb) or the altered state of a gene or a chrom (noun)
Biogeography
species that occur on islands are often closely related to species on the nearby mainland
According to this tree, what percent of the species seem to be extant (i.e., not extinct)?a. 66%b. 75%c. 25%d. 50%e. 33%
A
Overproduction
The potential for a species to increase its numbers
clock-like evolution
substitution rate = neutral mutation rate
Hardy-Weinberg Assumptions
Allele frequencies in a population will only stay the same (HW equilibrium) if several assumptions hold true:
 
1)no net mutations
2)no migration (no gene flow b/w populations)
3)random mating (allele frequencies do not change, genotypes may change)
4)population is very large (no genetic drift)
5)no selection (all survive and have equal fitness)
 
Under HW, allele frequencies do not change, and evolution does not occur.
 
EQUATION:
p^2 + 2pq + q^2 = 1
p^2 = probability of AA
q^2 = probability of aa
-to get probability, multiply frequencies of alleles)
Outside of his broad theories. What was Dawin's speciality?
Barnicles
Plato's philosphy
essentialism; eidos, the "form" or "idea," a transcendent ideal form imperfectly imitated by its earthly representations.
prezygotic barrier
A reproductive barrier that impedes mating between species or hinders fertilization of ova if interspecific mating is attempted.
phylogenetic reconstruction
to understand patterns of evolutionary change
when unrelated species have similar adaptations this has occurred
stabilizing selection
acquired characteristic
nonhereditary change made in response to the environment.
catastrophism
major changes in the earths crust that are the results of catastrophic event
synonymous vs non-synonymous mutation
synonymous are not expressed differently in the phenotype
Punctuated Equalibrium
New spiecies arise as others go extinct spontaneus species and rapid evolition
Scientific Theory
the best scientific explanation for a phenomenon
Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasinga. geographic isolation.b. gene flow.c. mutations.d. genetic drift.e. non-random mating.
B
Hadean eon (precambrian)
Formation of primordial soup and protobionts
Bergmann's rule
correlates latitude with body mass in animals
Biogeography- explaining contemporary patterns
phylogeography- combines fossil data current distribution, geology, and DNA to reconstruct the biogeographic history of organisms
 
nuclear markers:
-autosomal: biparental
-X chromosome: uniparental but essentially biparental
-Y chromosome: paternal
 
organellar markets: uniparental
-mtDNA maternal
-cpDNA maternal in angiosperms, paternal in gymnosperms
 
-In Chihuahua Spruce, mtDNA is very localized, as cones don't move around much, but cpDNA is different everywhere
What is sexual dimorphism?
Where different genders look different.
vestigial organs
structures that are reduced and no longer in related species
Define Analogous Structures.
Similar features of organisms that evolve independently
bird and bat wings are what because they evolved independently?
homoplasious
camouflage
allows a species to blend with their surroundings
Sickle-cell anemia
An inherited form of anemia caused by a mutation in the hemoglobin protein that causes the red blood cells to assume a sickle shape.
Definition Of
 
Vestigial Structures
a vestigial structure is an apparatus that had a use in the past, but overtime evolved to have no use.
Adaptive Radiation
specis in one area move and occupie new habitance and have slight changes in looks , adpat to  new enviroment.
 
what determines the rate at which disequilibrium goes to zero?
interloci distance
recombination rate
The equation p2+2pq+q2=1.0 describes:
A. the process of evolution
B. the size of a population
C. the rate of speciation of species p and q
D. the genotype and allele frequency of a population
E. the phenotypic frequency of a population
 
 
D. the genotype and allele frequency of a population
Linnaeus hierarchical classification scheme
Kingdom, Phylum, Class, Order, Family, Genus, Species (King Phillip Came Over For Good Spaghetti)
Species Concepts
About 20 species concepts (can be used in combination)
 
BSC (Biological Species Concepts)
-species are groups of potentially interbreeding populations which are reproductively isolated from other such groups
-produce viable and fertile offspring
-PROBLEMS?
-asexual species (how do you know if isolated?)
-unisexual
-geographic barriers (allopatric)/intrinsic barriers
-legal definition for Endangered Species Act
 
MORPHOSPECIES
-based on phenotype
-limitation fossils
-no soft tissue (don't see color, etc.)
-no behaviour, song, etc
-cryptic species
 
PSC (phylogenetic spcies concept)
-monophyletic group composed of the smallest diagnosable cluster of individual organisms within which parental pattern of ancestry and descent
-genet rees vs species trees
-identify monophyly (based on characters used)
-no reference to reproductive isolation (benefit)
-for monophyly to occur requires no gene flow for considerable amount of time
What is convergent evolution?
Same traits with different origins, caused by similar environments
Is sexual selection more important in the evolution of males?
Intrasexual selection...
-direct competition
-sperm competition
-infanticide
 
Intersexual competition
-female choice
 
Competition b/w males has led to extreme sexual dimorphism when males can potentially control large harems.
Strong relationships exist b/w fighting succes and reproductive success in elephant seals
Character state
One of the variant conditions of a character (e.g., yellow versus brown as state of the character “color of snail shell”).
natural selection
the process by which forms of life having traits that better enable them to adapt to specific environmental pressures, as predators, changes in climate, or competition for food or mates, will tend to survive and reproduce in greater numbers than others of
The presence of gills in both fish and human embryos is an example of ?
divergent evolution
What are the two types of phenotypic variation?
continuous and discrete
relative frequency
of an allele= the number of times an allele appears when compared with the total nmver of that type available
Genomic Imprinting (and life histories)
Depends on whether allele is paternally or maternally inherited.
Less than 50 traits
-most autosomal
-critical for embryonic development
 
During gamete formation allele for specific gene is silenced.
Pattern of imrinting differs in males and females (erase od imprint)
eg. lgf2 (insulin-like growth factor)
 
-if female, both get shut off
-both heterozygous.. depends on if it came from mom or dad (whether or not expressed)
-slide 4, life histories, page 11
 
Mammals
IGF-2
-paternal allele expressed
-encodes hormone that stimulates cell division
 
CI-MPR
-encodes protein that binds IGF-2
-maternal allele expressed
 
tug of war: male IGF-2 max. rate of cell division (use female's resources), female CI-MPR binds to excess IGF-2 to reduce cell division
 
Does this happen in animals without gestation? (eg frogs, chickens).. NO
-CI-MPR binding to IGF-2 originated after placenta
-genomic imprinting also found in plants
 
 
Genetic drift
change in a gene pool of a population due to chance
vestigial structure
a body structure that has no function in a present day organism but was useful to ancestors
How to calculate genetic diversity at the nucleotide level
 
Sample problem

Find the genetic diversity of these sequences
Nucleotide diversity: π = the average number of nucleotide differences pet site site between 2 sequences sampled at random
π = Sigma [pipjπij]
 
pi = frequency of allele 1
pj =frequency of allele 2
πij = average change = number of pairwise differences/number of nucleotides
 
A1 = 0.5
A2 = 0.25
A3 = 0.25
 
Sample question
π = A1*A2*(# difference nt/total nt) +
      A1*A3*(# difference nt/total nt) +
     A2*A3*(# difference nt/total nt) +
 
π =
(0.5)(0.25)(1/10) + (0.5)(0.25)(2/10) + (0.5)(0.5)(1/10)
 
= 0.04375
Lamarck's contributions to evolutionary thinking
Got the point of evolution, but the mechanism wrong-behavioral changes do not lead to genetic changes
who was the captain of the beagle? What was he like? How did he die?
Cpt Robert Fitzroy
 
emotionally unstable, had a violent tember and frequent mood swings
 
he committed suicide
 
 
What are the 5 main elements of Naturaul Selection?
1.Genetic variation 2.Environmental stress 3.Overproduction of offspring and a struggle for survival 4.Survival of the fittest 5.Increase in the number of individuals with characteristics suited to the environment
The four major fossil deposits
All of the deposits illustrate a full range of body plans present in a single site soon after cambrian diversity explosion.
Darwin - variational theory of change
natural selection - survival of the fittest
What ultimately drove D away from medical school?
The was appalled by cadaver dissections and the dark underbelly of the medical world (black market for bodies)
Linkage disequilibrium is formed in natural populations by the process of
all of the above; epistatic natural selection, random genetic drift, and gene flow
Conditions for trait to evolve
benefit x recipient to donor - cost > 0
why do pops rapidly lose neutral genetic variation when they experience bottlenecks?
because the rate of random genetic drift increases significantly when the pop size becomes very small. the number of Gens spent at low Ne will largely determine how much neutral variation is lost
What is the graph of stabilizing selection?
The middle of the graph has higher fitness than the rest.
He did what to help Darwin's theory?
He sent him a letter that showed all his findings, which made him publish The Orgin Of Species.
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