In addition, quite a few caecilians and some species of anurans and salamanders give start to live younger. Fish copy methods differ, however most fishes lay a lot of small eggs that are fertilized and scattered exterior of the physique. The eggs of pelagic (open ocean) fishes normally remain suspended in the open water, whereas many shore and freshwater fishes lay eggs on the bottom or among plants. The mortality of the young and particularly of the eggs may be very high, and often only some people develop to maturity out of tons of, hundreds, and in some cases tens of millions of eggs laid. © Comstock Images/JupiterimagesThe first fishes are thought to have emerged some 518 million years ago in the course of the Cambrian Period of Earth’s historical past.
Fossilized skeleton of Diplodocus carnegii, displaying an extreme example of the backbone that characterizes the vertebrates. The vertebrates traditionally … Read More