Re: how did dolphins evolve from dogs?

Hello,
Well the simple answer to your question is that dolphins did not evolve from dogs. This is very similar to the misconception that man evolved from chimps. Dolphins and dogs evolved from a common ancestor that was neither dolphin nor dog (just as humans and chimps evolved from an ancestor that was neither human nor chimp). The dolphins belong to the cetacea (a phylogenic classification) and dogs belong to the carnivora. Both of these have evolved from a group called the mesonychidae. There is a great dolphin website I found (http://library.thinkquest.org/17963/evolution.html) that has some nice information on dolphin evolution (with references!). The dolphins are more closely related to hippos and hoofed animals (than dogs), and it is suggested that they were once terrestrial also. They became aquatic and lost their legs so that they could utilize new resources (other aquatic life). This is, of course, extremely simplified and it would be best for you to go to the website itself. Another great website is the Tree of life (http://ag.arizona.edu/tree/ phylogeny.html). Here you can follow the phylogenetic tree, and it will tell you where some of the controversies are found. You can also see for yourself that dolphins didn't evolve from dogs! Take care.
Derrick