Biology 110 Unit 2 – Flashcards
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During his voyage around the world, Darwin was inspired to think about evolution by a number of different observations. What were they?
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Fossils, Geographical Distribution, Oceanic Islands
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Describe the term "natural selection."
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Individuals that have superior physical, behavioral, or other attributes are more likely to survive than others not so well endowed
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In natural selection, what factor determines "success"?
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those who can respond to the challenges of their environment become more common, "survival of the fittest"
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What insight did Darwin gain from reading Thomas Malthus's essay on human suffering?
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the inescapable consequence of the potential for human populations to increase faster than food supplies and other resources.
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What is the difference between Lamarkian and Darwinian evolution?
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Lamarckian evolution believes all acquired characters are inherited by the next generation. Darwinian evolution believes in survival of the fittest.
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Describe the difference between artificial selection and natural selection.
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whether the difference in reproductive success is driven by naturally occurring processes, or whether the selection is imposed by humans.
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How do vestigial organs, embryology, and molecular similarities among organisms relate to evolution?
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Vestigial organs, embryology, and molecular similarities in organisms show that the organisms have evolved in some way. It shows that there are some organs that they no longer need, all organism's embryos are almost the same, and that at the cellular levels all organisms are alike.
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microevolution
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changes in the gene pool of a population over time that result in changes to the varieties of individuals in a population.
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macroevolution
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Evolution happening on a large scale, e.g. at or above the level of a species, over geologic time resulting in the divergence of taxonomic groups.
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What is the smallest unit that can "evolve"?
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population
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How are divergence and convergence different?
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Divergence: The evolutionary process wherein a population of species diverge into two or more descendant species, resulting in once similar or related species becoming more and more dissimilar Convergence: A kind of evolution wherein organisms evolve structures that have similar (analogous) structures or functions in spite of their evolutionary ancestors being very dissimilar or unrelated.
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What is the difference between homologous and analogous structures? What are some examples of each?
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Homologous: Structures derived from a common ancestor or same evolutionary or developmental origin (cat, bat, bird) Analogous: Structures of different species having similar or corresponding function but not from the same evolutionary origin (dragon fly)
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What is the Hardy-Weinberg rule (What are the H-W equations, What do p and q stand for in the equations, What is the definition of Hardy-Weinberg equilibrium)?
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p + q = 1, p = frequency of the dominant allele, q = frequency of the recessive allele
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How do new alleles originate?
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mutation
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What are the criteria necessary for a population to be in Hardy- Weinberg equilibrium? How do these criteria relate to the factors involved in microevolution?
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Extremely large population size. (No genetic drift), No gene flow, No mutations, Random mating, No natural selection.
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How do new combinations of existing alleles originate?
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sexual reproduction
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genetic drift
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a change in a gene pool of a small population due to chance.
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founder effect
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small sample of gene pool leads to radical change in allelic frequency in subsequent generations, eg island populations (Galapagos).
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gene flow
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is a gain or loss of alleles from a population
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bottleneck effect
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disaster eliminates alleles from gene pool, eg. elephant seals.
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inbreeding
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The mating of two closely related persons.
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selective predation
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involves predators preferring prey of a certain size.
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What are the 5 (mechanisms of evolution) evolutionary forces that cause allele frequencies in population to change (deviate from the Hardy-Weinberg equilibrium)?
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Mutation, gene flow, genetic drift, nonrandom mating, natural selection.
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In a large sexually reproducing population, the frequency of an allele changes from 0.8 to 0.1. What can be deduced from this?
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evolution has occurred
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directional selection
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a mode of natural selection in which extreme values for a trait are favored over intermediate values
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disruptive selection
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a mode of natural selection in which a single phenotype is favored, causing the allele frequency to continuously shift in one direction
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stabilizing selection
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a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value
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What are the 6 types of prezygotic mechanisms discussed?
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temporal isolation, behavioral isolation, mechanical isolation, prevention of gamete fusion, ecological isolation, geographical isolation
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prezygotic isolating mechanisms
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prevent the formation of viable zygotes
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postzygotic isolating mechanism
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prevent hybrids from passing on their genes.
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Describe how genetic variation exists within a population and between populations.
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within-polymorphism between-geographic variation
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What is the biological species concept?
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A species is a reproductive community of populations (reproductively isolated from others) that occupies a specific niche (breed among themselves)
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How do the evolutionary species concept and the phylogenetic species differ from the biological species concept?
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Species as members of populations that actually or potentially interbreed in nature, not according to similarity of appearance.
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allopatric speciation
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occurs when a single species becomes geographically separated; each group evolves new and distinctive traits.
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sympatric speciation
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occurs when two individual populations diverge from an ancestral species without being separated geographically.
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What are some mechanisms of sympatric speciation?
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polyploidy, autopolyploidy, allopolyploidy
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polyploidy
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extra sets of chromosomes
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allopolyploidy
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hybrids that have a chromosome Number double that off their parents.
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autopolyploidy
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An occurrence where both sets of chromosomes in parents have been duplicated in the offspring, sometimes resulting in the formation of a new species.
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adaptive radiation
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The diversification of several new species from a recent ancestral source, each adapted to utilize or occupy a vacant adaptive zone
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The original source of all genetic variation is_____.
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mutation
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In evolutionary terms, an organism's fitness is measured by its _____.
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contribution to the gene pool of the next generation
