AP Science Writer
NEW YORK (AP) — A remarkable trove of fossils from Colorado has revealed details of how mammals grew larger and plants evolved after the cataclysm that killed the dinosaurs.
The thousands of specimens let scientists trace that history over a span of 1 million years, a mere eyeblink in Earth's lifespan.
Sixty-six million years ago, a large meteorite smashed into what is now the Yucatan Peninsula of southeastern Mexico. It unleashed broiling waves of heat and filled the sky with aerosols that blotted out the sun for months, killing off plants and the animals that depended on them.
More than three-quarters of species on Earth died out.
But life came back, and land mammals began to expand from being small creatures into the wide array of forms we see t