why do zebras have stripes? and why is a giraffes neck so long? and why did these species survive past darwin?

Answer 1

Let me answer both your questions:

(1) Zebras have stripes because their main predator, the lion, is color blind. So while to us they stand out strongly against their background, a lion has a very difficult time seeing them in tall grass.

(2) Giraffes are basically deers with very long necks - these necks evolved in order to help giraffes reach leaves at the top of trees (rather than the bottom, where they'd already been eaten by most other animals).

Answer 2

As weird as may seem any of those adaptation, you have not too much to be surprised at. Giraffe's long necks allow them to reach the food no other animals can reach, and that lack of competition for the source make giraffes a sucessful specie even when they have to contort like chinese acrobats to take a sip of water. Zebras live in packs, and their stripes altogether make difficult to know where does a zebra ends or begins, somewhat discouraging predators that find themselves trying to stalk something in a chaotic mass of white and black stripes. while isolated from other zebras, a specimen is most likely to become a next meal. Hmm, I wonder how a giraffe steak would taste like....

Answer 3

You have to understand that the phrase 'survival of the fittest' does not have to imply that what makes an animal fit is obvious to you. On the Giraffes they would have an obvious advantage of being able to reach food high up in a tree that other animals are unable to reach. This means that they may be able to survive even during droughts. As for the zebra/stripe thing I cant begin to guess how that might help them survive.

Answer 4

Zebras have stripes so that people can identify them from horses. Giraffes have a long neck so they can reach the branches of the trees to eat the leaves. There used to be short necked giraffes but they are now extinct because they starved to death.

Answer 5

What you're describing above is actually Lamarckian evolution, which was disproved a long time ago. Acquired traits aren't passed on, so how much a proto-giraffe stretched its neck (or didn't stretch its neck) would have no bearing on the neck length of its offspring. There are two main ideas in Darwinian evolution. The first is that there's natural variation within each generation - offspring aren't exactly like their parents, nor are they a perfect blend. Lets say that we have a group of proto-giraffes, with short necks (similar to horses). When two of those proto-giraffes get together and reproduce, some of those offspring will have necks shorter than their parents, some the same lengths as their parents, and some longer than their parents. The second idea is that there is selection from that pool of variants. Some will have traits that make it easier to survive, which boosts their chances of surviving long enough to reproduce. Some traits will make it harder to survive, lowering their chances. Back to the proto-giraffes from above, the ones with slightly longer necks will have a little more access to food, so they'll have a higher chance of surviving. This means they're more likely to have offspring, some of which will inherit their long-necked genes. These offspring will have access to more food, so they'll have a better chance of survival, and so on and so forth, until the longer-necked proto-giraffes have out-reproduced the shorter-necked ones, and all proto-giraffes have slightly longer necks. Repeat a bunch of times, and lots of small increases in neck length can add up to a big increase in neck length. The really important thing to remember is that evolution doesn't think ahead. Don't think of the proto-giraffes evolving long necks because they needed them. Rather, the proto-giraffes that happened to be born with sightly longer necks were at an advantage and were able to survive and reproduce more (producing more longer-necked offspring), and those born with slightly shorter necks were at a disadvantage and didn't reproduce as much. So, on to your questions below. Proto-giraffes probably ate leaves. It's important to think of evolution in terms of lots of tiny advantageous steps, rather than one big sudden requirement. Proto-giraffes had access to leaves on lower branches - the thing is, they had to share them with other animals. They still had food available on lower branches, but they had *more* food available higher up. As for where they originally came from, I don't know. An environmental change is certainly possible. Perhaps low bushes and grass became less common, or another species moved in and competed with them for food closer to the ground. If anyone out there has more specific information on this bit, I'll defer to them.

Answer 6

What you talk about? Darwin was human, and humans like zebras and giraffes, still exist.

What's the point?

Answer 7

Food is high...neck gets long...that is evolution

Stripes = camouflage