| Definitions | Scientists | Evolution | Definitions 2 | Long Answers |
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What is natural selection?
Changes in the frequency of traits (alleles) in a population over generations that occurs as a result of differential survival.
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Who is Darwin?
Has four observations of nature:
1) Members of a population vary in their traits 2) Traits are inherited from their parents 3) Species produce more offspring than can survive 4) Individuals with beneficial traits will survive and reproduce better, passing on their traits to their offspring |
What is an analogous structure?
structure that is similar in form or function on two different species, due to similar selection pressures not a common ancestry.
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What is reproductive isolation?
When two species/populations can no longer interbreed.
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Directional Selection - when conditions favor individuals with an extreme of a phenotypic range, shifting the population curve one direction.
Stabilizing Selection - selection pressures are exerted on both extremes, decreases variation in a particular trait. Disruptive Selection - Acts for both extremes and against the intermediate, results in polymorphisms or speciation. Frequency dependent selection - one phenotype is linked to the other phenotype, is a type of balancing selection
Describe Directional Selection, Stabilizing Selection, Divergent/Disruptive Selection & Negative Frequency Selection.
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What is evolution?
Descent with modification.
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Who is Linneaus?
Created the binomial nomenclature. Speculated that new species formed from hybridization or adapting to new conditions.
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What is the gene pool?
all copies of every type of allele at every locus in all members of the population
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What is the Founder Effect?
A few individuals give rise to a new population, with no gene flow, inbreeding and low heterozygosity thus constraining the path of subsequent evolution.
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It is a null hypothesis for evolution. It assums that the population is very large, has no new mutations, no gene flow, no natural selection and no sexual selection (random mating). p2+2pq+q2=1; p+q=1
What is the Hardy-Weinberg Equilibrium? Include the purpose, assumptions and the equations.
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What is artificial selection?
Selective breeding by humans is the force driving trait frequencies in a population.
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Who is Malthus?
Wrote an essay that humans were having too many children and were going to start fighting over food and land.
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What is the evidence supporting evolution?
Direct observations, homologous structures, biogeographic patters, genetics & the fossil record.
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What is relative fitness
How well an individual (particular genotype or phenotype) survives and reproduces relative to the other individuals/genotype/phenotype in the population.
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Gene mutation (DNA replication error) creates new alleles that provide variation in a population, is in the germ line cells (are heritable)
**Sexual reproduction increases variation due to crossing over in prophase I, fertilization and epigenetic influences**
How does evolution start?
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What is macro evolution?
Change in a line of descent through successive generations at species level or above.
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Who is Cuvier?
Father of paleontology & comparative anatomy. Believed that new species formed after catastrophes "catastrophism".
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What is a homologous structure?
Structure that is similar in two different species that is due to a common ancestor and develops from the same anatomical structure (same tissue in the embryo)
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What is the Biological Species Concept
one or more populations that descended from a common ancestral population, have genotypic and phenotypic similarity, are reproductively isolated from other species and produce fertile offspring.
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q=0.2.
p=1-0.2 p=0.8 2pq=2*(0.2)*(0.8) = 0.32 Aa individuals
In a HW population with two alleles, A and a, allele a has a frequency of 0.2, what is the frequency of the heterozygous individuals? Explain how you get the answer and provide the correct answer
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What is micro evolution?
Change in allele frequencies of a population in a relatively short period of time.
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Who is Lamark?
First to propose a mechanism for species to change, the principal of "use and disuse" where organisms gain or lose traits by excessive use or disuse.
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What is an adaptation?
A trait that enhances survival or reproduction. It will occur in an increased frequency in successive generations.
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What is genetic drift?
Chance events cause allele frequencies to fluctuate unpredictably from generation to generation especially in small populations, alleles can be lost or reduced due to chance occurrences, harmful alleles can become fixed, constrains direction of evolution
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populations separate into different species with no physical barrier. Can be due to resource division, hybridization, or polyploidy
What is sympatric speciation? What can cause it?
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