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33 Cards in this Set
- Front
- Back
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What is a clade?
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An evolutionary branch that includes a common ancestor and all its descendants,
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What is a cladogram?
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A system used to classify and arrange organisms in a phylogenetic tree.
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In what epoch did modern man first appear?
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Pleistocene
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What is adaptive radiation? How does it contribute to speciation?
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Evolution of a new species from a selective ancestor, continued adaptive radiation will eventually cause that the ability to interbreed is lost.
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What is a polyploidy? How is a polyploidy different from a diploid?
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When the number of chromosomes increases to more than 3n, diploids is only 2n
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7. Speciation is the process by which very similar organisms that once interbreed and shared their gene pool become separate species. How do allopatric speciation and sympatric speciation differ from each other?
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Allopatric is the separation as a result of a physical or geological change, while sympatric is genetic divergence from species within the same physical area.
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What are the postzygotic barriers?
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Hybrid Inviability: Embryo dies early, Hybrid infertility: Offspring is infertile (Mules)
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What are the prezygotic barriers?
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Different habitats, temperature, behavior, sperm cannot reach egg.
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Most populations of organisms that belong to different species are unable to mate and/or produce viable offspring. There are prezygotic barriers meaning before _________ and postzygotic barriers meaning after _________.
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conception
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Which scientist is given credit for presenting the modern concept of a species?
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Ernst Mayr
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If horse and donkeys are both found on a farm and they can interbreed, would they be considered the same species? Why or why not?
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No, because they do not produce fertile offspring.
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What two conditions must be meant for a population of organisms to be defined as a species?
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Ability to breed and produce fertile offspring
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What is meant by the term heterozygote advantage? How does this term apply to human evolution in Africa with the causative agent of malaria being the force of natural selection?
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The advantage of having both alleles for a specific gene.
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Directional
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One extreme phenotype is favored by natural selection, phenotype shifts in that direction, horses growing in size.
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Disruptive
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Natural selection to both extremes to the phenotype, small and big fish survive, medium ones don’t.
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Stabilizing
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When the intermediate or most common phenotype is favored.
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What factors of the non-living world affect natural selection?
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Weather conditions, dependent chiefly on temperature and precipitation.
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Natural selection may involve the biotic and abiotic environment. What components of the living world affect natural selection?
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Competition, predation, and parasitism.
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In class, we talked about various types of genetic drift. Be able to define a bottleneck and its consequences for a population of organisms.
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Bottleneck is when a catastrophic event drastically reduces the number of organism of the population, can change the allele frequency.
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Be able to explain the founder effect and its consequences for a population.
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The founder effect occurs when combinations of alleles occur at higher frequency in a population that has been isolated from a larger population.
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Natural selection may involve the biotic and abiotic environment. What components of the living world affect natural selection?
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Competition, predation, and parasitism.
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What is sexual selection? Are they examples of random or non-random mating?
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Favoring the traits that increase the likelihood of securing a mate. Non-random mating.
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How is it different from runaway sexual selection?
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Runaway Sexual selection is the portrayal of ridiculous physical traits.
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What is the difference between assorative and disassortive mating? Are they examples of random or non-random mating?
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Assorative is when mates are selected based on a similar phenotype, Disassortive involves mating with dissimilar phenotypes. Non-random mating.
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Using the Rat Snake as an example, which of the conditions in question #4 best explains the lack of speciation among the various populations of these snakes?
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Gene Flow
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What are the conditions that lead to microevolution?
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Mutations, Gene Flow, Non random mating, Genetic Drift, Natural Selection.
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Mutations
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Introduction of a new variation into a population
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Gene Flow
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When breeding members of a population leave or when new members enter
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Non Random Mating
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When males and females reproduce together strictly by chance.
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Genetic Drift
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Chance events that cause the allele frequency to change
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3. The Hardy-Weinberg equation is useful in defining the conditions that must be met for a population to remain in equilibrium. This equation also tells us that ________ alone is insufficient to lead to changes within the population.
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sexual reproduction
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What is meant by the term gene pool? Would you refer to the gene pool of an organism or only of a population of organisms?
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Various alleles at all the gene loci in all the individuals of a population. Population.
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How do scientists define a population of organisms?
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A single species occupying a particular area and reproducing with one another.
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