Evolution is the process by which this occurs and it is spread out over many generations. Thus, the short minimal definition of biological evolution is, Evolution is a process that results in heritable changes in a population spread over many generations. This is a good working scientific definition of evolution; one that can be used to distinguish between evolution and similar changes that are not evolution.
Bone, cartilage, or dentine is used in the Ostracoderm fish and turtles. Chitin forms the exoskeleton in arthropods including insects, arachnids such as spiders, crustaceans such as crabs and lobsters (see arthropod exoskeleton), and in some fungi and bacteria. Calcium carbonates constitute the shells of molluscs (see Mollusc shell), brachiopods, and some tube-building polychaete worms.
Many animals use basic tools, and the fact that chimps use tools means it's very likely that our last shared ancestor used them too around 7 million years ago. Tool use may also have been seen before then in other animals.arlier species of Homo, such as Neanderthals used tools several hundred thousand years before our species first entered the scene. There were other tool using hominid species that preceded them.