The galapagos islands are a home to many endemic species. these species are found nowhere else on earth. the picture shows some examples of marine iguanas and how they differ from island to island.

on isabella, they are huge, mostly dark, and have huge spikes down their back. on espanola, they are very colorful. on fernandina, they are dark and moderate in size.
how did these iguanas, with such physical differences from island to island, change over time?
a) the different populations of iguanas on each island were established separately. each population originated from s. america and most likely came over on floating vegetation.
b) according to the theory of evolution, the individual selects which traits are best suited to the environment and chooses to pass these traits on to offspring. because the island populations are isolated from each other, these differences accumulate over time.
c) marine iguanas acquire traits that are best suited to them during their lifetime and pass on these traits to their offspring. for example, some iguanas who need protection, will grow larger spikes on their head. this trait will then be passed to their offspring.
d) an original population of land iguanas came over on floating vegetation from south america. over time, two species evolved, land and marine. marine iguanas made their way to different islands and once isolated on their own islands, accumulated adaptations most suited to their island.