AP Biology 3.5 Evolution. What is the reproductive barrier in the video best described as?
|Evolve in changing environment||Reproductive isolation|
|Test Prep||AP Biology|
And here are the potential answers: Many species are seasonal breeders based on
favorable conditions, such as abundant food and water supplies.
Many species’ wives wish they were romantic breeders who would bring home flowers and [Rhino wife wishing for more romantic Rhino husband]
chocolates once in a while.
Species like ring-tailed lemurs, horses, hamsters, and groundhogs prefer breeding in spring, [two groundhogs together in a forest]
while sheep, goats, elk, and mice prefer the fall.
Rabbits, however, pay no attention to the calendar. [lots of rabbits together]
Though is this seasonal reproductive barrier best described as “mechanical”?
Well, “mechanical” refers to the fact that some species are unable to mate with [A snake and a turtle side by side]
other species because…well, physically they just can’t.
The mechanics of the process are incompatible, which means A is incorrect.
How about B?
Is seasonal mating a geographical reproductive barrier?
Let’s say a body of water separates one herd of hippos from another. [Two hippo's either side of a body of water]
While that would be a darn shame, it wouldn’t have anything to do with the seasons.
So B isn’t our answer, either. [Hippo entering the ocean]
Let’s look at answer “D”.
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]
Since this is a pretty big no-no in nature, a post-zygotic reproductive barrier kicks
in to insure that the hybrid is infertile and won’t reproduce. [Hybrid of zebra and horse disappears]
Since “D” is all about isolation mechanisms, we can eliminate it as our correct answer.
That leaves us just with “C,” temporal.
Temporal separation is defined as a mating barrier achieved by differences in the timing
of species’ mating seasons.
Looks like C is our right answer.
Now will someone please get that poor rhino a box of chocolates…? [Two rhinos sniffing for chocolates]