Organisms that belong to the kingdom Animalia. General characteristics of these organisms include: eukaryotic cell type, mitochondria, and a complex nervous system. This group of life includes organisms like sponges, jellyfishes, arthropods (insects, shrimp, and lobsters), mollusks (snails, clams, oysters, and octopuses), fish, amphibians (frogs, toads, and salamanders), reptiles (turtles, lizards, alligators, crocodiles, snakes), birds, and mammals (kangaroos, bats, cats, rabbits, elephants, whales, porpoises, monkeys, apes, and humans).