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.
a wide range of animals are considered to use tools including mammals birds fish cephalopods and insects rarely animals have been observed making their own tools e g primates sharpening a stick to use as a weapon or removing leaves and twigs from a branch and fishing for termites with a stem frayed by chewingool use has been reported many times in both wild and captive primates particularly the great apes the use of tools by primates is varied and includes hunting mammals invertebrates fish collecting honey processing food nuts fruits vegetables and seeds collecting water weapons and shelter