Mini test 3 -1

Mini Test 3

01 Biology

listen to a lecture in a biology class.

W: Our next topic is mimicry in animals. See, in nature, animals have different ways of defending themselves from predators.

Some animals change their behavior to become less appealing to those that are hunting them, such as oh, such as when an opossum plays dead.

But others have an evolutionary defense mechanism through which they are able to change their appearance in order to discourage predators.

This is called mimicry OK? Mimicry. But don’t confuse mimicry with camouflage. Camouflage is when an animal takes on the appearance, uh, looks like its surroundings, but mimicry refers specifically to the instances when animal models its appearance after another organism.

Are we clear with that? Great, why don’t we discuss some more specific types of mimicry then?

Well, then, I guess we can start with Batesian mimicry. Batesian mimicry is when an animal mimics the appearance of another in order to protect itself from predators.

The real distinguishing factor between Batesian mimicry and other types of mimicry is Batesian mimicry, the animal that changes its appearance has no characteristic of its own that would discourage predators otherwise.

Let me explain further… see, it isn’t as though animals just randomly pick another animal to mimic.

They model themselves after animals that either taster really icky, uh bad, or are poisonous.

By looking like a poisonous species, predators are going to pass over them when they are out hunting.

Are we all still on the same page? Why don’t I give you all an example just to clarify?

OK, so let’s consider the Brazilian butterfly Pierdiae. There’s no real reason why a bird wouldn’t want to eat one of these guys except for one thing − it looks exactly like a butterfly from the Heliconiidae family.

The Heliconiidae are not a species that birds are interested in eating because – well, they taste funky, you know, unusual and not at all tasty.

Just by having similar coloration as the Heliconiidae, the Pierdiae are able to escape getting eaten.

So basically, the tasty Pierdiae looks like the not-so-tasty Heliconiidae and thus avoids predation.

Pretty cool, huh? Anyway, the case of the Pierdiae butterfly was the first time that this type of mimicry was observed, by a man named Henry Bates, hence the name.

But don’t be fooled. Batesian mimicry occurs in all types of bugs, cockroaches, all different kinds. Scientists haven’t completely figured out how animals evolve to have the same coloring and features as other animals, but genetic research has revealed that the patterns of color inheritance is probably influenced by geography.

That means that bugs from different areas have different genes to determine which species they mimic.

If there aren’t any questions, I think we should talk some about Mullerian mimicry.

OK… after the discovery of Batesian mimicry, scientists started studying mimicry in all sorts of animals.

What scientists noticed, though, were animals that had a defense mechanism of their own, yet they still mimicked other species.

This was called the Batesian paradox, because it made no sense at all for an organism that was already unappetizing to predators to mimic another animal.

Then a German zoologist named Fritz Muller proposed that the reason an organism would do this so that predators would learn that lesson about not eating them from another inedible species that looks like them.

Does that make sense? Here, let me put it this way… See, birds and other predators aren’t born knowing which bugs are good to eat and which ones are going to make them sick or whatever.

So when a bug with its own defense mechanism mimics another type of bug, it benefits because then the predator learns not to eat them by first trying a different but similar-looking species.

And once the predator learns, it’s going to avoid bugs that resemble it. Think of it as kind of like a warning pattern that’s shared between many bugs.

In fact, the group of bugs that share the pattern, which is called a mimicry ring, by the way, usually go through some signal standardization.

All that means is that all the animals in the mimicry ring evolve in order to have the same warning signal.

1) How does the professor organize the information about mimicry that she presents to the class?

2) Why does the professor mention opossums?

3) What does the professor imply when she says this: But don’t confuse mimicry with camouflage. Camouflage is when an animal takes on the appearance, uh, looks like its surroundings, but mimicry refers specifically to the instances when animal models its appearance after another organism.

4) What does the professor imply about how predators choose their prey?

5) Based on information from the lecture, to which type of mimicry does each statement relate? Place a checkmark in the correct box.