Evolution is evidence that life changes over time and an example is the Blue Moon Butterfly of the Samoan islands was
being attacked by a parasite which destroyed male embryos. This led to a
gender imbalance whereby males made up only 1% of the butterfly
population. However, within ten generations (~1 year) males had returned
to 40% of the population. This is not because the parasite has
disappeared, it is still present, but it is no longer deadly to male
embryos. This case shows how a mutation giving an advantage can rapidly
spread throughout a population. Any male with the ability to survive
infection would be able to mate with a great many females, due to the
paucity of other males, and spread his immunity through the gene pool.
Fossils are also evidence that life changes over time and the evidence is that paleontologists
and zoologists have long accepted that birds and reptiles are related. The two
groups share many common traits including many skeletal features, the laying
of shelled eggs, and the possession of scales, although in birds, scales are
limited to the legs. Among modern birds, the embryos even have rudimentary fingers
on their wings. In one modern bird, the South American hoatzin the wings of the juvenile have large moveable claws on the first
and second digits. The young bird uses these claws to grasp branches.
