AP Biology; Chapter 24 Review

Rank the following in order from most general to most specific: •gamete isolation •reproductive isolating mechanism •sperm-egg incompatibility in sea urchins •prezygotic isolating mechanism

2, 4, 1, 3

Know the difference between biological, morphological, phylogenic, and ecological species concepts.

Biological- not a species if they can not make or produce viable offspring. Morphological- defines a species by what they look like. (body shape and structural features) Phylogenetic- trace of the phylogenetic history of a species by comparing its characteristics with other organisms. Ecological- defines a species in terms of its ecological niche. (where they live)

Three populations of crickets look very similar, but the males have courtship songs that sound different. What function would this difference in song likely serve if the populations came in contact?

a prezygotic isolating mechanism; behavioral isolation.

Define hybrid zone

a region in which members of different species meet and mate

Dogs (Canis lupus familiaris) and gray wolves (Canis lupus) can interbreed to produce viable, fertile offspring. These species shared a common ancestor recently (in geologic time) and have a high degree of genetic similarity, although their anatomies vary widely. Judging from this evidence, which two species concepts are most likely to place dogs and wolves together into a single species?

biological and phylogenetic

In which order do the following occur during allopatric speciation: Genetic Drift, Genetic Isolation, Divergence.

genetic isolation, genetic drift, divergence

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

habitat isolation

What are hybrid zones, and why can they be viewed as "natural laboratories" in which to study speciation?

hybrid zones are regions where members of different species meet and mate. they can be viewed as "natural laboratories" because they have the potential to create a whole new species.

Summarize key differences between allopatric and sympatric speciation. Which type of speciation is more common, and why?

in allopatric speciation, a new species forms in geographic isolation from its parent population. Sympatric speciation requires the emergence of a reproductive barrier that isolates a subset of a population from the remainder of the population in the same area. Allopatric, because sympatric is rarer and can occur when gene flow to and from the isolated subpopulation is blocked.

How many genes influence the formation of new species?

it only takes one, but it could be more than one.

Most causes of speciation or relatively slow, in that they may take many generations to see changes, with the exception of what?

polyploidy

Two species of frogs belonging to the same genus occasionally mate, but the embryos stop developing after a day and then die. Is this a prezygotic or postzygotic reproductive barrier? Which type?

postzygotic; reduced hybrid viability

Contrast punctuated equilibrium and gradualism

punctuated equilibrium is periods of stasis punctuated by sudden change while gradualism is small changes that occur over time.

Mules are sterile hybrids. Which postzygotic reproductive barrier is this an example of?

reduced hybrid fertility

What is the largest unit within which gene flow can readily occur

species

Describe gametic isolation

sperm of one species may not be able to fertilize the eggs of another species. (pollen is a form of sperm)

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it?

sympatric speciation; habitat differentiation

Define macroevolution

the broad pattern of evolution above a species level.

When is reinforcement likely to occur?

when barriers of reproduction are being strengthened; decrease in hybrids.

When is fusion likely to occur?

when barriers of reproduction are weakened; increase in hybrids