What observations did Darwin make during his time on the Galapagos Islands?

Question

What observations did Darwin make during his time on the Galapagos Islands?

What did Darwin infer about how things may have evolved from his observations of life on the Galapagos Islands?

Answer 1

Darwin made detailed sketches and observations of a variety of flora and fauna (plants and animals)--focusing on the variations that made these varieties different from those of the same secies that lived elswhere.

His essential inference is that from time to time, "mutations" occurred that resulted in the new varieties emerging (the word mutation, BTW, is from the Latin for "change"). Based on this and his other work, he suggested that this was also how new species emerged over time.

One thing that is often misunderstood is that this is entirely different from the process of natural selection. Natural selection is a readily observed process in nature (and known, if informally, long before Darwin). Essentially, it says that in any population, those members who are best adapted to a given environment are more likely to survive and reproduce.

Natural selection comes into play where Darwin's theory is concerned only in that he said that whether a new species would survive would be determined by how well adapted to its environment it was. If the "mutations" made a new species better able to survive, than likely it would--if not, it would be unlikely to last very long. But the process of natural selection has nothing to do with the processes that give rise to new varieties or species--that operates independantly. You might think of natural selection as a sort of "judge" that decides if a new species will "make the grade."

Answer 2

The big thing he discovered were finches. The important thing to remember is that these birds were different than mainland(South American) finches and different from one another, with a species unique to each island. Each had a beak specialized for its island, such as a large beak for cracking large nuts, or a small beak for small ones. He also discovered everything else the Galapagos is known for, including the giant tortoise and the marine iguana.
Darwin hypothesized that finches naturally have a diversity of beak size, with some birds having larger ones than others in a population. If the island these birds are on has only large nuts, then the birds with smaller beaks will die off, not being able to crack those nuts and, thus, starving. From there, birds with even larger beaks will survive better(have more offspring) than those with somewhat large beaks, up to a point. this is because they don't need to spend as much time cracking nuts and time is valuable, especially in nature, where disease and predators always roam free and where mating opportunities are usually scarce. In this way, average beak size increases overtime.

hope I explained this well enough

Answer 3

Darwin figured that the Galapagos was populated by animals from Ecuador and Peru, perhaps by swimming, flying or on a log. But somehow they ended up on these islands permanently separating themselves from their fellow species members in South America. Over the course of hundreds of generations each species changed, a little, adapting to their island environment.

Answer 4

READ THE BOOK.
It's absolutely brilliant - you can see the theory of evolution as if it's swimming around just under the surface.

Answer 5

Turtles = tasty. And great for long storage and then eating later.

Sorry, I should be going to bed. I think the real answer has something to do with finches - try wikipedia on it.