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149 Cards in this Set
- Front
- Back
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evolution
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changes in genetic composition of a population from generation to generation
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What was the ideas of the origins of life before 1600
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6000 yo and the world and animals were all made perfect
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What was the idea of the origin of life in the 1700s
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Linnaeus began organizing genus and species
Buffon and Darwin gpa had speculated that living change had occured over time due to the discovery of fossils |
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What were the ideas of Lamarck and the origins of the earth?
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He compared living species and fossils
He believed that animals through use and disuse would grow parts of the body that would get stronger. He believed that offspring could inherit those modifications |
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Lamarck and internal force
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innate drive to be complex
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evolution
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changes in genetic composition of a population from generation to generation
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What was the ideas of the origins of life before 1600
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6000 yo and the world and animals were all made perfect
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What was the idea of the origin of life in the 1700s
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Linnaeus began organizing genus and species
Buffon and Darwin gpa had speculated that living change had occured over time due to the discovery of fossils |
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What were the ideas of Lamarck and the origins of the earth?
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He compared living species and fossils
He believed that animals through use and disuse would grow parts of the body that would get stronger. He believed that offspring could inherit those modifications |
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Lamarck and internal force
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innate drive to be complex
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how did darwin come to his conclusions in origin of species
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he went on the HMS Beagle and on his way collected a lot of organisms, analyzed fossils, looked at animals isolated on the galapagos
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Natural selection
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a process in which individuals with a certain inherited trait leave more offspring than individuals with other traits
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what is the mechanism of evolution
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natural selection
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what are darwins finches an ex of
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natural selection
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does evolution happen to inidividuals
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no
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explain the idea of descent with modification
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all organisms came from one ancestor and overtime evolved leading to diverse populations
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artificial selection
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when humans select desired traits
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How did Malthus affect Darwin
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he proposed the idea that populations have a carrying capacity, which for darwin created an environment that leads to natural selection
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give examples of transitional forms
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a horse with four toes- 3 toes- 1 toe (today)
a whale w/ pelvis and hind limbs |
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Homology
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organisms with a common history
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vestigal structures
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remnants of freatures that seved important functions to ancestors
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convergent evoltuion
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the independent evolution of features in lineages that are different, but end up having similar traits.
ex: sugar glider vs. flying squirrel |
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analogous
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features shared because of convergent evolution
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heritable variability
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referes to different natural variation for traits
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monomorphism
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type of heritable variability but it refers to only 1 type of trait that is heritable (no change)
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polymorphism
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type of heritable variability that refers to one type of trait that has a lot of variation
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Are all traits heritable?
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No
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What are the conditions for evolution/natural selection?
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-the resources of the world are finite: not all organisms can survive
-some individuals have more reproductive success than others -some differences are inherited by offspring -over time survival charateristics become more common in populations |
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What is the solution to heritable variation?
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mutation
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mutation
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change in DNA sequence
*must be heritable |
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point mutuation
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chemical changes in a single base pair of a gene in a DNA sequence
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Give a summary of what happens in a point mutation
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mutation --> change amino acid sequence --> change in protein and conformation
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what are other ways that mutation occurs but is not heritable
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ribosomes make a mistake
RNA polymerase makes a change |
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Base substitution mutation
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one base replaces another
types: silent, missense, nonsense |
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Silent
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that that ends up coding for the same amino acid
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missense
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mutation that ends up changing the codon to code for a different amino acid
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nonsense
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mutation that will code for a stop codon to early
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Sickle cell anaemia as a mutation
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missense:
CTT--> CAT changes protein from glu to val |
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Insertion/deletion
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addition/loss of a nucleotide pairs in a dna sequence
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frameshift
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when less than 3 bases are eleted/insterted which leads to a frameshift in DNA
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how do mutations happen
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spontaneous: error in dna syntheis, loss of base, modify base
extrinsic: caused by a mutagen |
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mutagen
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phsyical/chemical agent that interacts w/ DNA
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how does UV cause mutation
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kink helix and block transcription
dna repair enzymes usualy help this |
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microevolution
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focus on evolutionary change in specific populations. looking @ change in alleles over time
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phylogenetics
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study of evolutionary relatedness amoung various groups of organisms
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discrete characteristics
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determined by a single gene locus
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quantitative charcter
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vary with population because they are influenced by multiple genes
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mutations in a genetic line show what
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the past genetics
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deleterious mutaiton
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bad
insertion/deletion, missense |
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neutral mutation
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missense or silent
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gene pool
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the total of all genetic variation in a sexually reproducing population
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how are gene pools described
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phenotype, genotype, and allele frequency
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phenotype frequency
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# of phenotypes seen in population / total population
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genotype frequency
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# of genotypes seen in population/ total
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allele frequency
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# of alleles in population for a given trait/ (total population x2)
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hardy weinberg equation
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p2 + 2pq + q2
p + q = 1 |
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assumptions of hardy weinberg
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1. no mutation to introduce new alleles
2. no migration from other populations 3. matin occurs at random 4. no fluctuations in population size 5. all genotypes produce equally well |
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What is the Hardy Weinberg Theroem
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That allelic frequencies are conserved and genotypic frequencies are conserved after 1 generation
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If one of the HW conditions are not met, what is implied/
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That deviations are taking place that will lead to evolution
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null hypothesis
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describes an aspect of statistical data and is assumed as true unless data contradicts it
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can a null hypothesis be accepted?
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no it can either be rejected or not rejected
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what does the HWE act upon
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individual genes
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What are methods of genetic variation
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sexual reproduction
mutation |
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How does sexual reproduction maintain genetic variation
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it makes new combinations of existing alleles
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how does mutation maintain genetic variation
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creates new alleles from existing and new genes
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how frequent does mutation occur
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1/10^5 or 10^6 gametes have it
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heterozygosity
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percent of loci that are heterozygous
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Identify the three mechanisms of what happens to a mutated gene
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1: a mutated gene will lead to a misfolded protein, which will cause an essential biological function to be altered. This leads to the death of the organism and usually loss of the mutated gene.
2: One copy of a duplicated gene is mutated. This leads to an old biological function being maintained and a new biological function arising 3: new genes are made through rearrangement of genetic information. This occurs through 2 different methods. First, new exons are created through recombining exons between different genes. Second, alternative splicing of exons occurs in transcription. |
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vestigial genes
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genes that exist in the genome without a function
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Can eukaryotic organisms incorporate other species dna into their own
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in unicellular, but not multicellular
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gene flow
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transfer of alleles into or out of a population
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what is an example of gene flow
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the mongol invasion bringing type B blood into europe
wind blowing pollen |
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what is a problem with genetic variation in gene flow
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homogenization of populations
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inbreeding and its affects on genetic variation
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mating between genetically related individuals.
leads to an increase in homozygousity genotype frequency will change but not allelic frequency |
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outcrossing and its affects on genetic variation
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mating between nonrelated individuals
increases heterozygosity non change in allelic frequency |
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assortative mating
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mating between similar individuals
may lead to an increase in homozygousity |
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disassortive mating
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mating between dissimilar individuals
increases heterozygousity |
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sexual selection
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partners chosen according to physical or behavioral characteristics
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sexual dimorphism
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marked differences between sexes in secondary sexual traits
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intrasexual selection
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competition within one sex for members of the opposite sex
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intersexual selection
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"mate choice"
individual of one sex are choosy in selceting the other sex |
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genetic drift
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change fluxuations in genetic diversity and allele frequencies
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how are small populations affected by genetic drift
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the smaller the population, the greater the genetic drift
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fixation of an alleles
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100% of the population will contain that allele
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mutation drift
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usually most mutations are lost quickly
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the founder effect
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a small gorup of individuals are isolated from the large popuation
usually results in disorders |
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bottleneck effect
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sudden change in environmental conditions that leads to a major drop in population
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what are the effects of genetic drift
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-significant on small populations
-causes allele frequencies to change -loss of genetic variation -cause harful alleles to become fixed |
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4 postulates of natural selection
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-the world is finite, therefore not all organisms will survive
-some org. have a better change of reproducing than others because not all org. have the same traits -some differences can be inherited -over time the survival characteristics become more common in a given species |
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population genetics view of natural selection
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any allele that leaves more copies of itself than its alternative will dominate the population
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what are traits that are chosen
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predator avoidance
resistance to disease withstanding env. conditions mating success |
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3 types of selection
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directional
stabilizing disruptive |
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directional selection
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conditions that favor individuals exhibiting one extreme of a phenotypic range
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stabilizing selection
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conditions that favor intermediates
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disruptive selection
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favors both ends of a phenotpic range
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fitness
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contribution of an individual to the gene pool of the next generation
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relative fitnes
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contribution of a genotype to the next generation as compared to an alternative genotype that has been designated @ 1
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Why do recessive traits not leave a gene pool?
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because of heterozygosity
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frequency dependent selection
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dependent selection fitness of phenotype if it becomes to common
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oscillating selection
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fitness varies with environment
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heterozygote advantage and preserving genetic variation
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it maintains the presence of dominant and recessive alleles
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limitations of natural selection
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pleiotropy and epistasis
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speciation
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the process which one species splits into two or more species
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microevolution
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looks at 1 species
change in allele frequencies in a population over time |
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macroevolution
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looks at multiple species
major transformations over time resulting from prolonged microevolution |
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species
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a group of populations whose members have the potential to inbreed in nature and produce viable offspring
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conspecifics
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potential to in breed in nature and produce viable, fertile offspring
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limitation of definition of conspecifics
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does not included asexual organisms and fossils
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prezygotic barriers
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habitat isolation
temporal isolation behavioral isolation mechanical isolation gametic isolation |
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habitat isolation
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organisms that are spacially separated
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temporal isolation
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separated by what time of day organisms emerge
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behavioral isolation
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no recognition as a mate or having different courting rituals
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mechanical isolation
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morphological differences
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gametic isolation
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gametes of organisms won't fuse
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post zygotic barriers
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reduced hybrid viability (impair ability to survive)
reduced hybrid fertility (can't produce offspring) hybrid breakdown (1st gen is fertile and following generations aren't) |
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allopatric speciation
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individuals are geographically separted from others of the original population
separated populations will speciate enough that when they are brought back together they won't produce viable offspring |
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sympatric speciation
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requires a reproductive barrier within a population
speciation that occurs within populations in the same geographic region |
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examples that can cause sympatric speciation
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polyploidy, sexual selection, habitat differentiation
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hybrid zone
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region in which members of different species meet and mate and produce viable offspring
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how a hybrid zone forms
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a populations is barred from gene flow with the rest of the population
it begins to diverge it completes speciation gene flow with the rest of the population is reestablished |
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outcomes for hybrids
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reinforcement
fusion stability |
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reinforcement
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increases reproductive barrier
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fusiona
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weakens the reproductive barrier and fuses the species
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stability
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continues production of hybrid individuals but also individuals that aren't hybrids continue as well
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punctuated equilibrium
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periods of apparent stasis puncuated with sudden evolutionary change
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examples of speciation resulting from gene change
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land snails: 1 gene
monkey flowers: small # of genes |
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adaptive radiation
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periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles
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Is evolution goal oriented?
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no
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Evolutionary Novelties
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complex forms adapt from basic structures that performed the same function
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heterochromy
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differential timing of development
altered timing of development of organs that lead to different appearances |
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allometric growth
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difference in growth in organs
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paedomorphosis
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adult rentention of juvenille morphology
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Hox genes
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master regulatory genes that determine
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phylogenetics
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study of the evolutionary history of a species or group of species or group of species
studies common ancestry genetic histories |
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what determines a phylogenetic tree
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DNA, fossil record, history and timing of continental drift, compared embryology
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Hierarchical classification categories
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Domain
Kingdom Phylum Class Order Family Genus Species |
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Convergent evolution
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acquisition of the same traits through unrelated lineages
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clade
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monophyltetic group
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cladograms are based on
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derived characteristics
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parsimony
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simplest situation that could happen
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what is the most parsimonious phylogenetic tree?
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one with the fewest evolutionary events of fewest DNA changes
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What is the largest unit within which gene flow can readily occur
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species
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What must occur during a period of geographic isolation in order for two sibling species to remain genetically distinct following their geograhic reunion in the same home range?
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reproductive isolation
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What has been the rapid method of speciation in plants
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polyploidy
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allopolyploid
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Allopolyploids are polyploids with chromosomes derived from different species
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Plant species A has a diploid number of 12. Plant B is 16. a new species arises from A and B as an allopolyploid. What is its ploidy?
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28
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According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that
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speciation occured rapidly in geologic time
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what types of mutations could occur that doesn't change a polypeptide
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silent mutation
intron mutation mutation of a non coding region |
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what does the heterozygote advantage mean in terms of fitness?
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that it is more fit than either homozygote
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