There was abundant plant and animal life under those conditions: 200 to 150 Ma is pretty much the Jurassic period and 400 to 600 Ma would have encompassed the Cambrian explosion. According to Wikipedia mean temperatures during the Jurassic period were about 3C and during the Cambrian about 7C above today's. Certainly nothing like Venus where surface temperatures are around 480C. Almost no known life could survive those temperatures, except perhaps some of the lifeforms found around black smokers.