Life first appeared in Earth's primordial seas some 3.6 billion years ago and evolved into a wide diversity of marine and terrestrial creatures before dinosaurs arose. Unicellular organisms, echinoderms, mollusks, insects, arachnids, crustaceans, fish, sharks, mosses, ferns, conifers, amphibians and many reptiles appeared before the dinosaurs and continue to evolve today.
Dinosaurs ruled our planet throughout the Mesozoic, which stretched from 225 to 65 million years ago (MYA), but other life forms also arose during that Era. Turtles, crocodilians and the earliest mammals appeared in the Triassic Period (225-190 MYA), ancestral birds and flowering plants graced the Jurassic Period (190-135 MYA) and the Cretaceous Period (135-65 MYA) witnessed the rise of ants, social bees, snakes, marsupials and the first deciduous trees.
Since the end of the Mesozoic (65 MYA), when dinosaurs became extinct, these "terrible lizards" live on as birds and Earth's mammals have exploded in number and variety. Primates, bats, cetaceans, manatees, rodents, canids, felines, ruminants, horses and essentially all of our modern mammals arose after the Age of Dinosaurs. Hominids have walked the Earth for no more than 6 million years and the human species is less than 150,000 years old.
