<Tr> <Td> 251.4 Ma </Td> <Td> The Permian--Triassic extinction event eliminates over 90 - 95% of marine species . Terrestrial organisms were not as seriously affected as the marine biota . This "clearing of the slate" may have led to an ensuing diversification, but life on land took 30 million years to completely recover . </Td> </Tr> <P> From 251.4 Ma to 66 Ma and containing the Triassic, Jurassic and Cretaceous periods . </P> <Table> <Tr> <Th> Date </Th> <Th> Event </Th> </Tr> <Tr> <Td> </Td> <Td> The Mesozoic Marine Revolution begins: increasingly well adapted and diverse predators pressurize sessile marine groups; the "balance of power" in the oceans shifts dramatically as some groups of prey adapt more rapidly and effectively than others . </Td> </Tr> <Tr> <Td> 248 Ma </Td> <Td> Sturgeon and paddlefish (Acipenseridae) first appear . </Td> </Tr> <Tr> <Td> 245 Ma </Td> <Td> Earliest ichthyosaurs </Td> </Tr> <Tr> <Td> 240 Ma </Td> <Td> Increase in diversity of gomphodont cynodonts and rhynchosaurs </Td> </Tr> <Tr> <Td> 225 Ma </Td> <Td> Earliest dinosaurs (prosauropods), first cardiid bivalves, diversity in cycads, bennettitaleans, and conifers . First teleost fishes . First mammals (Adelobasileus). </Td> </Tr> <Tr> <Td> 220 Ma </Td> <Td> Seed - producing Gymnosperm forests dominate the land; herbivores grow to huge sizes to accommodate the large guts necessary to digest the nutrient - poor plants . First flies and turtles (Odontochelys). First coelophysoid dinosaurs . </Td> </Tr> <Tr> <Td> 205 <P> Ma </P> </Td> <Td> the Massive extinction of Triassic / Jurassic, that wiped out most of the group of pseudosuchians and was given the opportunity of dinosaurs including the Apatosaurus, Tyrannosaurus, Perrotasaurus, and Stegosaurus to enter its golden age . </Td> </Tr> <Tr> <Td> 200 Ma </Td> <Td> The first accepted evidence for viruses that infect eukaryotic cells (at least, the group Geminiviridae) existed . Viruses are still poorly understood and may have arisen before "life" itself, or may be a more recent phenomenon . <P> Major extinctions in terrestrial vertebrates and large amphibians . Earliest examples of armoured dinosaurs </P> </Td> </Tr> <Tr> <Td> 195 Ma </Td> <Td> First pterosaurs with specialized feeding (Dorygnathus). First sauropod dinosaurs . Diversification in small, ornithischian dinosaurs: heterodontosaurids, fabrosaurids, and scelidosaurids . </Td> </Tr> <Tr> <Td> 190 Ma </Td> <Td> Pliosauroids appear in the fossil record . First lepidopteran insects (Archaeolepis), hermit crabs, modern starfish, irregular echinoids, corbulid bivalves, and tubulipore bryozoans . Extensive development of sponge reefs . </Td> </Tr> <Tr> <Td> 176 Ma </Td> <Td> First members of the Stegosauria group of dinosaurs </Td> </Tr> <Tr> <Td> 170 Ma </Td> <Td> Earliest salamanders, newts, cryptoclidids, elasmosaurid plesiosaurs, and cladotherian mammals . Sauropod dinosaurs diversify . </Td> </Tr> <Tr> <Td> 165 Ma </Td> <Td> First rays and glycymeridid bivalves </Td> </Tr> <Tr> <Td> 163 Ma </Td> <Td> Pterodactyloid pterosaurs first appear </Td> </Tr> <Tr> <Td> 161 Ma </Td> <Td> Ceratopsian dinosaurs appear in the fossil record (Yinlong) and the oldest known Eutherian Mammal appear in the fossil record: Juramaia . </Td> </Tr> <Tr> <Td> 160 Ma </Td> <Td> Multituberculate mammals (genus Rugosodon) appear in eastern China </Td> </Tr> <Tr> <Td> 155 Ma </Td> <Td> First blood - sucking insects (ceratopogonids), rudist bivalves, and cheilostome bryozoans . Archaeopteryx, a possible ancestor to the birds, appears in the fossil record, along with triconodontid and symmetrodont mammals . Diversity in stegosaurian and theropod dinosaurs . </Td> </Tr> <Tr> <Td> 130 Ma </Td> <Td> The rise of the angiosperms: Some of these flowering plants bear structures that attract insects and other animals to spread pollen; other angiosperms were pollinated by wind or water . This innovation causes a major burst of animal evolution through coevolution . First freshwater pelomedusid turtles . </Td> </Tr> <Tr> <Td> 120 Ma </Td> <Td> Oldest fossils of heterokonts, including both marine diatoms and silicoflagellates </Td> </Tr> <Tr> <Td> 115 Ma </Td> <Td> First monotreme mammals </Td> </Tr> <Tr> <Td> 110 Ma </Td> <Td> First hesperornithes, toothed diving birds . Earliest limopsid, verticordiid, and thyasirid bivalves . </Td> </Tr> <Tr> <Td> 106 Ma </Td> <Td> Spinosaurus, the largest theropod dinosaur, appears in the fossil record </Td> </Tr> <Tr> <Td> 100 Ma </Td> <Td> Earliest bees </Td> </Tr> <Tr> <Td> 90 Ma </Td> <Td> Extinction of ichthyosaurs . Earliest snakes and nuculanid bivalves . Large diversification in angiosperms: magnoliids, rosids, hamamelidids, monocots, and ginger . Earliest examples of ticks . Probable origins of placental mammals (earliest undisputed fossil evidence is 66 Ma). </Td> </Tr> <Tr> <Td> 80 Ma </Td> <Td> First ants </Td> </Tr> <Tr> <Td> 70 Ma </Td> <Td> Multituberculate mammals increase in diversity . First yoldiid bivalves . </Td> </Tr> <Tr> <Td> 68 Ma </Td> <Td> Tyrannosaurus, the largest terrestrial predator of what is now western North America appears in the fossil record . First species of Triceratops . </Td> </Tr> </Table> <Tr> <Th> Date </Th> <Th> Event </Th> </Tr>

When did the first mammals appear on planet earth
find me the text answering this question