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13 Cards in this Set
- Front
- Back
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Coyne and Orr’s studies of reproductive isolation and genetic divergence between pairs of Drosophila populations and species showed that... |
among recently diverged populations, premating isolation tends to be stronger than postmating isolation. |
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The notion that a species is a single lineage of populations or organisms that maintains a separate identity from other lineages is called the _______ |
evolutionary species concept - it has its own evolutionary tendencies and historical fate |
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The difference between primary and secondary hybrid zones is that primary hybrid zones _______, while secondary hybrid zones _______. |
are formed in situ as natural selection alters allele frequencies in continuously distributed populations; arise when two formerly allopatric species come in contact again |
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Suppose that two populations sharing many of the same gene lineages become reproductively isolated from each other. Over time, different lineages are lost in each population, and eventually these populations may speciate. Which of the following describes how genetic lineages change over time in this hypothetical scenario? |
Polyphyly (describes a group of organisms whose last common ancestor is not a member of the group) → paraphyly (group which does not include all its descendents) → monophyly(common descent from a single ancestor) |
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Even though species typically are defined by their reproductive isolation, the propensity of organisms to interbreed or to produce fertile offspring cannot always be determined experimentally. In the absence of experimentation, evolutionary biologists can infer reproductive isolation by measuring |
ALL OF THE ABOVE a. differences in phenotypic characters. b. whether loci are in Hardy-Weinberg equilibrium indicating a single population. c. total similarity of genetic markers. d. whether independent genetic markers are in linkage disequilibrium or not. |
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The biological species concept has been widely adopted, but it also has some practical difficulties (species are groups of actually/potentially interbreeding natural pop that are reproductively isolated from other such groups). Which of the following is not one of these difficulties? |
The concept is poorly defined. p 446, concept IS defined WELL |
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According to the biological species concept, speciation consists of the evolution of biological barriers to gene flow. The most important distinction is between _______ and _______ barriers. |
prezygotic; postzygotic |
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Which of the following ideas is central to the biological species concept? |
Reproductive isolation |
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Which of the following terms refers to a variant of a species that is associated with a particular type of habitat (usually used within the botanical literature)? |
Ecotype |
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Which of the following is not one of the possible fates of a hybrid zone? |
Extinction of all populations due to hybridization |
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In many groups of insects, the genitalia of related species differ in morphology, such as these three Drosophila species below. One explanation for the differences is that this trait is not highly constrained. |
the “lock and key” hypothesis. |
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Reproductive isolation as a result of Dobzhansky-Muller incompatibility is caused by |
b. the inability of two or more loci from different lineages to function well together. |
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What class of barrier to gene flow would we be observing if we noted that the offspring of a lion and a tiger (two different species) are awkward, gangly beasts that have poor survival in the wild? |
Postzygotic barrier |
