Once upon a time, long long ago, there lived a race of lizard-like creatures on a swamp world that revolved around a nearby star. This world was hot, wet, steaming and green. Much of it was sea, but the land that existed was mostly covered in marshes or swamps or tropical forests. The lizard creatures dominated in every aspect - the sea, the land, the sky. There were many different kinds of reptiles, ranging from quick and sleek to huge and powerful, but all were tough and suited to the swampy climate.
They had ruled the planet for millions of years. It seemed that the planet had been especially created for them to dominate it, with their lizard skins, their powerful bodies, and their wrenching jaws. The lizard creatures could never imagine a time when they would not be the supreme creature on Swamp World.
But then something happened. The lizard creatures didn't comprehend the change, but over time Swamp World became less.... well, swampy. Was it that asteroid? Was it the locking up of vast amounts of carbon deep in the earth's crust? Did the Earth's poles change? The reptiles didn't know, but nevertheless they were severely impacted by the changes.
Temperatures cooled and the seas receded as the oceans were locked up in ice caps at the poles. Despite all their power, their toughness, their ubiquitous presence, the lizards began to die out. Many survived - but mostly only the small reptiles. The largest ones could not adapt to this new world where they no longer dominated, this world that no longer suited them so perfectly.
As the climate cooled, other species were able to compete with the lizards. They filled the gaps that the reptiles once had monopolized. The world now was much more hospitable to their smaller bodies, opposable thumbs, social and communication skills, and tool-making abilities.
And now, swamp world is no longer recognizeable. It became a beautiful planet with a variety of climates - icy poles, wind-swept tundras, breathtaking mountains, gorgeous coral reefs, temperate forests, tropical paradises. We have no memory of that long distant past, when the world was an inhospitable place for us, where we would have been only a tiny snack for those lizard kings.
But just as long ago, the climate changed and eliminated much of the habitat of the reptiles, reducing them from the dominant life-form to a much smaller creature living in the niches of the planet, our climate is mutating once again; growing warmer and wetter, melting ice caps and swelling tides, with ever more violent and unpredictable weather.
Who knows what will emerge to take advantage of this new climate, this new planet being birthed before our very eyes?