Bio II Evolution and Phylogeny
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rrichter815 on March 3, 2012
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English | Chemistry |
|---|---|
 Darwin was influence by | Georges Buffon, Georges Cuvier, Jean-Baptiste Lamarck, Charles Lyell |
| Gene variation is the________of evolution | raw material |
| Darwin published things with______who had the same basic ideas as him | Alfred Russell Wallace |
| Georges Buffon | Suggested that the earth was much older than previously believed |
| Georges Cuvier | By documenting fossil discoveries, showed that extinction had occurred |
| Jean-Baptiste Lamarck | Suggested that living species might change over time |
| Charles Lyell | Argued that geological forces had gradually shaped the earth and continue to do so |
| Evolution is... | 1. Change in allele frequency of a POPULATION over time 2. Descent with modifications 3. Diversity 4. Unifying 5. Common descent 6. Intellectual Framework that allows us to scientifically explain nature |
| Hardy-Weinberg principle -equation helps to ________should be there if evolution is not occurring | Null hypothesis when researchers want to test whether evolution is affecting a particular gene -predict number of alleles |
| Evolutionary mechanisms | 1.ONLY natural selection produces adaptation 2. Genetic drift 3. Gene flow 4. Mutations 5. Assortative mating (nonrandom) |
| HW predicts... | genotype and phenotype frequencies of genes in a population from one generation to the next |
| HW allows for the ______ of how _______ is maintianed and altered populations | quantitative analysis, genetic diversity |
| The only mechanism that leads to adaptation | natural selection |
| Polymorphism | more than one phenotype is maintained at a locus |
| Pattern:all populations exhibit genetic variation among individuals at a large number of ..... | loci (gene locations in the genome) |
| Genetic Drift | Random change in allele frequencies Regardless of fitness Chance Sampling of a population changes the genetic makeup Effects are most significant in SMALL populations |
| Genetic drift effects are more significant in _____ populations | small |
| Bottleneck effect | surviving members of a catastrophic event can have different allele frequencies than the source population and consequently, the new population experiences evolution -cause death of large, random proportion of the individuals in a population |
| Causes of bottleneck effect | famine disease rapid environmental change |
| Founder's effect -caused by: | founding members of a new population can have different allele frequencies than the original source population and, consequently, the new population experiences evolution -group of individuals may leave a population and become the founding members of a new, isolated population |
| Gene Flow | When individuals migrate into or from populations -allele frequencies may change |
| Nonrandom (assortative) mating | when phenotypically similar individuals mating |
| Most common type of nonrandom mating | inbreeding -ex self-fertilization in plants |
| Nonrandom mating does not affect ______ frequency but shifts _______ frequency and reduces number of _______ | allele, genotype, heterozygotes |
| Mutation | source of variation spontaneous or caused by mutagens silent, or will alter protein structure/function |
| Mutation by itself does _______ cause ______, natural selection must act on the variation caused by mutation in order for it to occur | not, adaptation |
| Natural selection | involves differential survival and/or reproduction due to differences in phenotype adults (random mating)→juveniles (selection)→ adults |
| Fitness -is measured by | the probability of contribution of an individual to the next generation, mediated by natural selection -the number of surviving offspring left in the next generation |
| Differential survival and/or reproduction leads to change 1. offspring inherit the _______ genes 2. population in next generation are______ to local conditions,______ 3. change continues with ______ fueled by_____ | 1. more favorable 2. better adapted, more fit 3. ongoing, new variations |
| Selection pressures | 1. environmental change- climate, weather 2. disease 3. competition for resources- food, habitat 4. competition for mates |
| A simple model for selection | population with genetic variation + selection pressure→ differential survival/reproduction→accumulation of favorable genes→new genetic variations introduced→population with genetic variation |
| Allele frequencies reflect a ______ between opposing processes -evolutionary forces can _____ each other | balance -counteract |
| Frequency-dependent selection | favors a phenotype depending on its frequency in a population |
| Negative frequency dependent selection | rare phenotypes are favored |
| Positive frequency dependent selection | common phenotypes are favored |
| Oscillating selection | one phenotypes favored at one time, different phenotype favored at another time |
| Heterozygote advantage | favors the heterozygote genotype |
| ________ is responsible for sickle cell anemia | missense mutation |
| Stabilizing selection | variants at both ends of the range of variation are selected against |
| Disruptive selection -results in... | variants in the middle of the range of variation are selected against -dimorphisms, polymorphisms |
| Directional selection | selection pressures drive the population toward one end of the range of variation |
| Selection has ______ | biological and physical limits |
| Intense directional selection can _____ variation | lessen |
| Pleiotropy | a single gene has multiple phenotypic effects |
| Epistasis | interaction between alleles of different genes affect a single trait |
| Evolution by natural selection occurs when: | 1. heritable variation leads to 2. differential success in survival and reproduction |
| Peter and Rosemary Grant | long-term research medium ground finches Isle Daphne Major found that beak form and body size and heritable |
| Descent with modification -two testable predictions about the nature of species | change over time produced modern species from ancestral species -they change through time and -they are related by common ancestry |
| Geologic time scale | a relative time scale based upon fossil content can date fossils in this way |
| Transitional forms | found through fossils traits that are intermediate between earlier and later species |
| Vestigal trait | reduced or incompletely developed structure that has no reduced function but is clearly similar to functioning organs or structures in closely related species -evidence that characteristics of species have changed over time |
| Human tailbone is a _____ trait | vestigal |
| Structural homology 2 predictions | similarities in adult morphologies 1. traits are similar in different species because they are related to each other by common descent 2. types of similarities would not occur if species were created independently of one another |
| Biogeography | patterns of plant and animal relate to their distribution history -explains why species from different continents have a common ancestor |
| Convergent evolution | different species exposed to similar selection pressures evolve similar adaptations |
| Mechansims that stop gene flow between populations are either _______ or _________ | prezygotic or postzygotic |
| Postzygotic mechanisms | prevent the development of viable or fertile adults after fertile adults after fertilization has occurred |
| Prezygotic mechanisms | prevent mating or fertilization |
| Biological species concept | species are interbreeding natural populations that are reproductively isolated from other such groups -NO gene flow between these populations |
| _______ is the outcome of reproductive isolation | speciation |
| Prezygotic barriers | habitat isolation temporal isolation behavioral isolation morphological isolation gamete isolation |
| Habitat isolation | occurs when groups mate in different habitats ex. mountains where species live on either side |
| Temporal isolation | occurs when groups live in the same physical space, but do not encounter each other when mating |
| Behavioral isolation | occurs when behaviors associated with mating differ significantly ex blue footed boobies |
| Morphological (mechanical) isolation | occurs when reproductive organs are no longer compatible |
| Gamete isolation | occurs when gametes are able to encounter each other but are not biochemically compatible -fertilization does not occur |
| Postzygotic barriers | hybrid inviability hybrid sterility hybrid collapse |
| Hybrid inviability | fertilization occurs but hybrid embryos die during development |
| Hybrid sterility | hybrid embryo survive, but hybrid's gametes are not viable |
| Hybrid collapse | genetic incompatibility w/self or parents behavior inappropriate by either parent ecologically intermediate between species |
| Modes of speciation | allopatric founder effect parapatric sympatric |
| Allopratic | speciation occurs in geographic isolation -caused by geological events -allows differences to accumulate |
| Founder effect | a special kind of allopatric speciation in a small isolated population on the edge of a species range |
| Parapatric | speciation in adjacent populations with some gene flow |
| Sympatric | speciation without isolation opposite of allopatric live in same place at the same time major mutations may produce a population that can not breed with the parent population |
| Ring species | a special type of allopatric speciation two non-interbreeding populations connected to each other by gene flow through another population no point where one species starts and the other stops |
| Sympatric speciation can happen in response to _________ | disruptive selection |
| Polyploidy | sympatric speciation having more than two sets of chromosomes most common in plants |
| Autopolyploid | the chromosomes all come from the same species self polypoid |
| Evolutionary species concept | species are single evolutionary lineages with unique tendencies and historical fate |
| Biological species concept doesn't always work... | Classifying: asexual species (does not involve interbreeding), fossil species, ring species, hybridizing species And determining when one species has changed into another -cannot determine reproductive isolation |
| Allopolypoid | rare in animals common in plants polyploids w/ chromosomes derived from different species ex. silvery salamander |
| Hybridization | the interbreeding of closely related species |
| Comparing genomes (________) of different species provides a powerful tool for exploring the ___________ among organisms | (entire DNA sequences) Evolutionary divergence |
| Comparative genomics | Study of the relationship of genome structure and function across different biological species |
| With proper and independent data __________ can be calibrated | genome evolutionary rates |
| Human and Pufferfish genomes -Last common ancestor _______ -_____ human genes no counterparts in Fugu -Human genome ____ repetitive DNA, but only ______ fugu sequence repetitive | 450 mya 25% 97%, 6% |
| Human and mouse genomes -Human has _____ million more nucleotides that the mouse -________ genes and they share ______ -Diverged about ____ mya -______ genes unique to either organism (___) | 400 25,000, 99% 75 300 (1%) |
| Human and Chimpanzee genomes -Diverged _____ mya -____ difference in insertions and deletions -____ of human-specific indels lead to loss of function changes--- may be loss of hair or longer cranium -______ of the two genomes have consistent differences in a single nucleotides -Genomes are similar around _______ -_____ human/chimp genes are identical | 4.1-6 1.5% 53 1.06% 98% 30% |
| Aneuploidy | duplication or loss of an individual chromosome plants tolerate better than animals |
| _________ of segments of DNA is one of the greatest sources of _______ traits | duplication, novel |
| Paralogues | two genes within an organsim that have arisen from the duplication of a single gene in an ancestor |
| Orthologues | reflects conservation of a single gene from a common ancestor |
| Horizontal gene transfer | genes hitchhike from other species (HGT) can lead to phylogenetic complexity contrast to vertical gene transfer (genes passed generation to generation) ex virus, bacteria |
| Humans have _______ fewer than other primate -may be a result of ______ | one chromosome chromosome fusion |
| Much of the genome is _________ DNA Repetitive DNA is often from _________ DNA _____ of animal and ______ of plant genomes | noncoding retrotransposon 30%, 40-80% |
| _________ discovered by Barbara McClintock They are "________" Can be _______ from DNA and inserted somewhere else and can _______ phenotypes | Transposons "jumping genes" removed, disrupt |
| Transposition | process in which genes can move around to different positions within genome |
| Why does a mouse develop into a mouse and not a human? | Genes are expressed at different times Different tissues Different amounts Different combinations |
| FOXP2 | mutation in a single point in gene prevents speech in chimps, gorillas, orangutans and mice expressed in areas of brain that affect motor function role may be in neuromuscular pathway used in making sounds |
| Heterochrony -could affect a gene that controls transition from ______ to _______ -might result in ________, but is _______ | alterations in TIMING of development events due to a genetic change -juvenile to adult -increased fitness, rare WHEN |
| Most mutations that affect developmental regulatory genes are ________ | lethal |
| Homeosis -mutations can arise ________ or by _______ in lab -bizzare phenotypes would have ________ in wild | alterations in the spatial pattern of gene expression WHERE spontaneously, mutagenesis little survival value |
| Only ______ gene families regulate animal and plant development | 2 dozen |
| Hox (homeobox) -In plants: -In animals: | genes establish body plan by specifying when and where genes are express Family of transcription factors -shoot growth and leaf development -establish body |
| Transcription factors | proteins that stabilize binding RNA polmerase to promoter regions |
| MADS box genes -is a dna_______ -________ exists in the coding region of MADS box sequences -changes can have ________ effects on the development of an organism | code for transcription factors establish body plan of plants, especially flowers have some variation in some areas of the genes -binding motif -variation -dramatic |
| Are AP3 and PI genes necessary for petal development? Complete AP3 gene= No AP3 gene C terminus= PI C terminus replaces AP3 C terminus= | petals, stamen no petals, no stamen no petals, some stamen |
| Evolution of chordates can partially be explained by _________ of an existing gene for a ________ function _________ gene encodes a transcription factor expressed in developing _________ This gene encodes a protein domain called ______, transcription factor In mice and dogs, mutation causes _______ Humans have ________ but no ______ other genes are needed | co-option, new brachyury, notochord T box short tail wild-type brachyury, tail |
| Homologous | same gene, new function same source |
| Homoplastic (analogous) | same/similar function, different genes same form -convergent evolution -evolutionary reversal |
| Origin of convergence difficult to understand | different developmental pathways may have been modified not clear whether it is the same or different genes responsible |
| Insect wing patterns are -Distal-less: required for________development expression predicts _______ placement _________ production triggered | homoplastic origins of patterns developed using existing regulatory patterns limb eyespot pigment |
| Evolutionary trees provide understanding important biological framework | What is the evolutionary history of Homo sapiens? What is the origin of disease? What is the evolutionary history of plant species we use for food? |
| Phylogeny | BUILD TREES A hypothesis of relationships among species The evolutionary history of a group of taxa an evolutionary tree (aka phylogenetic tree) |
| Systematics | USE TREES TO CLASSIFY the reconstruction and study of evolutionary relationships the science of using phylogenetic relationships to classif and name organisms |
| Taxonomy | CLASSIFY AND NAMING the study of the classification of organisms |
| Monophyletic group: | a common ancestor and all of its descendants |
| Armoracia is ______ | monophyletic make fruit, but fruit don't have any seeds |
| Taxon | any group of organisms |
| Phenetic approach | relationships among organisms are based on phenotypic similarity |
| Cladistic approach | relationships among species are based on shared, derived characters |
| Cladistic method of reconstructing evolutionary relationships | 1. choose ingroup 2. choose outgroup 3. identify characters 4. determine character states |
| The outgroup is used to establish _______ for each character, which is whether character state is ______ or ______ Reveals direction of _________ Character state found in outgroup is considered ________ | polarity ancestral, derived evolutionary change ancestral |
| Synapomorphy | shared, derived characteristics |
| Autapomorphy | a derived character state that is unique to a single taxon |
| Apopmorphies | derived character states |
| Cladogram | hypothesis of evolutionary relationships based on shared, derived characters (synapomorphies) |
| Plesiomorphies | ancestral character states |
| Symplesiomorphies | shared ancestral character states |
| Parisomy | hypothesis that requires the fewest assumptions is favored |
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