Flashcards
Evolutionary Bio Unit 1
Flashcards do conjunto (73)
- 1What is HIV?virus that caused acquired immune deficiency syndrome(AIDS)
First discovered in the US in 1981
intracellular parasite that cannot reproduce on its own
Invades specific types of cells in the immune system - 2How is HIV established?When bodily fluid holding the virus usually blood or semen, carries it from an infected person directly onto a mucous membrane or into the bloodstream of an uninfected person and also can be transmitted needle sharing, blood transfusions, breastfeeding, or childbirth
- 3replication phase of HIVlatching onto two proteins on the surface of the host cell. After adhering first to CD4 HIV attaches to a second protein called a coreceptor (CCR5)
- 4Cells vulnerable to HIVDendritic cells, effector and memory T cells which all carry CD4 and CCR5
- 5Cycle of HIV1. HIV's extracellular form (virion) encounters a host cell
2. HIV's gp 120 protein binds to CD4 and corrector CCR5 on host cell
3. HIV RNA genome, reverse transcriptase, integrase, and protease enter host cell
4. Reverse transcriptase synthesizes HIV DNA from HIV's RNA template
5. Integrase splices HIV DNA into host genome
6.HIV DNA is transcribed to HIV mRNA by the host cell's RNA polymerase
7. HIV mRNA is translated to HIV precursor proteins by host cell's ribosomes
8. Protease cleaves precursors into mature viral proteins
9. New generation of virions assembles inside host cell
10. New visions bud from host cell's membrane - 6How does the human body respond to infectionDestroy virions in bloodstream
Kills its own infected T cells and macrophages - 7Rgenetic information does not follow thee familiar route from DNA to mRNA to protein, instead it flows from RNA to DNA to mRNA to protein
- 8How does AZT work?AZT fools reverse transcriptase into picking it up instead of thymidine because they are similar in structure and this causes reverse transcriptase to stop and become stuck. AZT interrupts the pathway to new viral proteins and new virions
- 9Why didn't AZT work well?Because reverse transcriptase is error prone, mutations arise frequently. Which affect how well reverse transcriptase can differentiated between AZT and thymidine
This is natural selection acting on HIV for low-mistake reverse transcriptase, evolving newly evolved trait AZT resistance - 104 step process on why AZT works in the short run and fail in the long run1. transcription errors lead to mutations in reverse transcriptase gene
2. Mutations produce variability in enzyme function
3. Some virions survive better than others in the pre scene of AZT
4. The advantageous mutations are passed on to the offspring of AZT-resistant virions - 11Coreceptor inhibitorsblock HIV from attaching to cells
- 12Entry/Fusion inhibitorsbar entry to host cells
- 13non-nucleotide RT inhibitorsblock reverse transcriptase allosterically
- 14Integrase inhibitorsBlock viral DNA incorporation into host DNA
- 15Protease Inhibitorsblock the enzyme that cleaves precursor proteins to allow maturation of virions
- 16Modern HAART cocktailshigh effective, with life expectancies for HIV+ patients now equivalent to the HIV population. Even patients with AIDS have vastly lengthened lifespans. Its a much harder drug to become resistant
- 17Where did HIV come frommost closely related to primate SIVS
Beatrice Hahn made a phylogeny of HIV-1 (chimps) HIV-2(mangabeys)and many SIVS - 184 groups of HIV-11. Group M-Major/Main
-Has differentiated into 9 subtypes
-From chimps, global
2. Group N- Non-M Non-o/new
-<20 infections, recorded
-from chimps, Cameroon only
3. Group O- outlier
-high diversity, west central Africa
-from chimps?
4. group P-pending
-One case so far
-from gorillas? or both chimps or humans then gorillas - 19why is HIV fatal?In non-ape primates, SIV does not cause any detectable disease
virulence is caused by reproduction rate of virus - 20Correlation between lethality and transmission-If the host lives long ether then the HIV population persists longer too
To persist beyond the life span of the host, a viral population must at some point colonize a new host. this means that the second level of natural
- high replication rate means more transmissions and Yeats but also fewer years to spread
selection favors intermediate virulence - 21second level of natural selection-when there are differences among viral strains in their ability to move from one host to another. Strains that are good at getting transmitted to new hosts will become more common over time, and the strains that are bad are less frequent
- 22Transmission rate hypothesisnatural selection favors high rates of virulence for STI's when partner exchange is frequent, low rates of virulence when partner exchange is infrequent
- 23virulence results from...trade offs between natural selection working at two levels: within host and between host
- 24Charles DarwinEnglish naturalist (1809-1882)
Participated in the voyage of the HMS Beagle around South America
Did not "invent" the theory of evolution
Discovered a major mechanisms of how evolution works-natural selection
published on the Origin of species in 1859 - 25Lamark's theory of Evolutionthrough the use and disuse and the inheritance of acquired traits
but the mechanisms he proposed are unsupported by evidence - 26Voyage on the BeaglePlants and animals of temperate South America are more like those of tropical south America than like those of temperate Europe
Plants and animals of the Galapagos similar to those on South American Mainland - 27Uniformitarianismearth has been undergoing the same neutral processes since beginning
Earth much more than a few thousand years old - 28In 1838 Darwin-started to read Thomas Malthus, An Essay on the Principle of Population
-Discussed how populations of organisms over-reproduced and would cause famine and disaster
-formulated his theory of evolution by natural selection - 29Theory of Special creationEach organisms created by a deity independently
species were immutable
the earth is very young - 30HomologySimilarity resulting from common ancestry
-Anatomical, genetic, developmental - 31Homolgy must be caused by?relatedness
- 32Relatedness of Life formsGalapagos Islands
-similar but distinct species on each island
-mockingbirds,lizards,finches, and tortoises
Population must have arrived from South America on one island and spread to others, species diverged separately on each other - 33Evidence for Common Ancestryring species of Ensatina salamanders
- 34Evidence from living speciesVestigal structures (useless)
- 35Change in timecan be identified at structural, developmental, and genetic levels
-Blind salamanders with eyesockets
-whales and snaked with hind legs
Direct observation of change in species
Soapberry bug evolving with shorter beaks - 36Functional genesexons, introns, promoters
- 37processed pseudogenenon-functional and is missing introns and promotors
Arise from reverse transcription of mRNA (resulting DNA is inserted at another locus) - 38evidence from fossil recordsused to think that if we looked hard enough we would find those fossilized species alive somewhere
extinction eventually become known as a fact
special creationists then asserted that extinct species were killed by biblical flood - 39Law of Successionextinct species are ancestors of living species
they did not die in a flood leaving no descendants
extinct species are often found in areas with similar living descendants - 40transitional formsDarwin was concerned that no transitional forms have born found
In 1860 the first archaeopteryx was found - 41Environmental changeMarine organism fossils found in inland deserts and on high mountains
- 42Principle of UniformitarianismFirst articulated by James Hutton
- Is the claim that geological processes taking place now operated similarly in the past (volcanoes, erosion, earthquakes)
Opposed the principle pf catastrophism and that geology results from catastrophic events - 43Geological time scalesequence of nested periods of time established through relative dating, associated with distinctive fossil floral and fauna
Absolute ages were added once radiometric dating became available - 44Contiental driftFormally proposed in 1912 by Alfred Wegener, denounced by geologist though Wegener suggested seafloor spreading
-noted continental shelves fit together like a puzzle, geological structures like mountain ranges and unique rock strata and fossils match those alignments
Seafloor magnetic striping was another major line of evidence, recording down changes in Earth's magnetic field in the continual production of new rock at mid-ocean ridges - 45Radiometric datingabsolute daring of rocks
unstable isotopes decay at a constant rate, rate is not affected by temp, pressure or moisture
Half-life of isotopes are known so you can measure the amount of the og and the daughter isotopes in a rock sample - 46Methodological Naturalismthe only hypotheses researchers propose to account for natural phenomena, and the only explanations they accept, are hypotheses and explanations that involve strictly natural processes and causes
- 47Four steps of scientific method1. Description of a phenomenon or group of phenomena
2. Formulation of a hypothesis to explain the phenomena
3. Use of the hypothesis to predict the existence of other phenomena or to predict quantitatively the results of new observations
4. Performance of experimental tests of the predictions by several independent experimenters and different kinds of properly performed experiments - 48Darwin's four postulates1. Individual species are variable
2. Some variation is heritable
3. More young are born than survive
4.Survival and reproduction are not random - 49Darwin's four postulates (HIV)-there is variation among virions in their resistance to AZT
-The ability to distinguish between AZT and thymidine is inherited
-Not all virions are able to infect T cells and reproduce
-The virions that distinguish AZT the best produce more offspring and are naturally selected for - 50Alfred Russel Wallace-independendtly developed the theory of natural selection before Darwin published On the origin of species
-not famous because Darwin's argument was more complete and he published first
-the four postulates can be independently verified ( all are testable) - 51Darwin's fitnessability of an individual to survive and reproduce in its environment
- 52AdaptationIs a trait that increases an individual's fitness in its environment
are enhanced by natural selection - 53Testing Postulate 1: Are populations variable?-because each finch is banded, each can be measured
(weight, wing length, beak width and depth and length)
-Beak depth is variable within this species - 54Testing postulate 2: Is variation heritable?-Beak depth variation can be genetic or environmental
-must estimate heritability
proportion of variation observed in a pop. due to variation in the effects of genes
compare parents and their offspring - 55Parent offspring correlation influencesmisidentified paternity (extra-pair mating)
nest parasitism
maternal effects
shared environments - 56testing Postulate 3: Is there an excess of offspring so that only some individuals live to reproduce?- In 1977 there was a severe drought and 84% of finch population died
-in normal times 89% of finches die before they can reproduce
-clearly, more individuals are born than can survive and reproduce - 57Wallace example of exponential growth and potential role in selection1 pair of birds produce 4 your per year
-each pair reproduces 4 times in their lifespan
-After 15 years, one pair will produce 10 million if all of their offspring reproduce - 58Darwin example of exponential growth and potential role in selectionAn average elephant lives 100 years, produces about 6 progeny between ages 30-90
-after 750 years, 1 pair will produce 19 million progeny if all their offspring reproduce - 59Testing postulate 4: Are survival and reproduction nonrandom?-After drought, the Grants measured the surviving birds again
-Found that finches with the deepest beaks survived more than others
-Deep beaks were favorable during drought because only one plant produced a lot of fruit (tribulus custodies) - 60The nature of natural selectionnatural selection acts on individuals but evolution occurs in populations
natural selection acts on phenotypes but evolution changes allele frequencies - 61Evolution of Darwinism-Darwin did not know how variability was created
-Thought that variation in organisms would be used up eventually
-we now know new variation is created continuously by mutation
-darwin didn't know how traits were inherited
-believed in blending inheritance
-Individual traits would be lost by merging with other traits
-After Mendel was re-discovered we know that alleles are inherited independently - 62Lord Kelvin-established that the earth was 15-20 million years old based on earth's rate of cooling
-not enough time for all species on earth to evolve
-did not account for convection or radioactive decay, incorporation of both proved that earth was much older, sufficiently old for all species to evolve - 63Modern SynthesisBetween 1932-1953 where a series of landmarked books were published that successfully integrated genetics with Darwins four postulates and led to a reformation of the theory of evolution
-contributed major advances in population genetics that helped explain how Mendelian genetics were in fact consistent with evolution-mutation, inbreeding, drift, adaptive landscapes, and the mathematical framework for predicting evolution - 64The modern synthesis was grounded in two propositions-gradual evolution results from small genetic changes that are acted upon by natural selection
- the origin of species and higher taxa (macroevolution) can be explained in terms of natural selection acting on individuals and changing populations (microevolution) - 65individuals that survive and reproduce or who reproduce the mostare those with alleles and allelic combinations that best adapt them to their environment
- 66Evolution vs Creationism-fundamentalist groups had lobbied for the Tennessee legislature to pass the Bulter act making teaching human evolution in state-funded schools a crime
-The ACLU offered to defend anyone prosecuted for violating the act
-Tennesse at the time required teachers to use a textbook that included a chapter on evolution - 67hypothesisa proposition
- 68facta hypothesis that has become so well supported by evidence that we feel safe in acting as if it were true
- 69theorydoesn't mean unsupported speculation- a mature, interconnected body of statements, based on reasoning and evidence, that explains a wide variety of observations
- 70Systematicsstudy of biological diversity and evolutionary relationships of organisms
Made up of taxonomy and phylogenetic - 71taxonomyclassifying organisms in groups
-taxon= species or genus or kingdom
-the science of classifying organisms - 72Phylogeneticsreconstructing evolutionary relationships
- 73Rules of taxonomyclassification is governed by formal rules that scientists must follow
naming conventions, native classi
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- 1 evo bio FlashCards sobre Evolutionary Bio Unit 1, criado por Selena Frederick em 06-09-2022.
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