ShmoopTube

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Here’s your Shmoop du jour, brought to you by

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barriers, the sworn enemy of Ronald Reagan. [Raegan smashing down a barrier and Mikhail Gorbachev appears]

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Check out the following:

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Two neighboring species mate during different seasons.

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This reproductive barrier is best described as….what?

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And here are the potential answers: Many species are seasonal breeders based on

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favorable conditions, such as abundant food and water supplies.

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Many species’ wives wish they were romantic breeders who would bring home flowers and [Rhino wife wishing for more romantic Rhino husband]

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chocolates once in a while.

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Species like ring-tailed lemurs, horses, hamsters, and groundhogs prefer breeding in spring, [two groundhogs together in a forest]

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while sheep, goats, elk, and mice prefer the fall.

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Rabbits, however, pay no attention to the calendar. [lots of rabbits together]

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Though is this seasonal reproductive barrier best described as “mechanical”?

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Well, “mechanical” refers to the fact that some species are unable to mate with [A snake and a turtle side by side]

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other species because…well, physically they just can’t.

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The mechanics of the process are incompatible, which means A is incorrect.

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How about B?

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Is seasonal mating a geographical reproductive barrier?

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Let’s say a body of water separates one herd of hippos from another. [Two hippo's either side of a body of water]

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While that would be a darn shame, it wouldn’t have anything to do with the seasons.

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So B isn’t our answer, either. [Hippo entering the ocean]

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Let’s look at answer “D”.

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A hybrid zygote is formed when no barriers exist to interspecies mating. [A zebra and a horse together and a hybrid of the two appears]

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Since this is a pretty big no-no in nature, a post-zygotic reproductive barrier kicks

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in to insure that the hybrid is infertile and won’t reproduce. [Hybrid of zebra and horse disappears]

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Since “D” is all about isolation mechanisms, we can eliminate it as our correct answer.

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That leaves us just with “C,” temporal.

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Temporal separation is defined as a mating barrier achieved by differences in the timing

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of species’ mating seasons.

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Looks like C is our right answer.

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Now will someone please get that poor rhino a box of chocolates…? [Two rhinos sniffing for chocolates]

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