02:53
Survivors: Long-Term Survivors
Despite the challenges of long-term survival on Earth, some phyla-including sponges, jellyfish, arthropods and mollusks-have endured for hundreds of
Subject: phyla
Transcript: [narrator:] some phyla, including sponges, jellyfish, arthropods and mollusks, have survived for hundreds of millions of years, even in the most
01:06
Survivors: Early Invertebrates
The first animals on Earth were invertebrates-animals without backbones-and they diversified rapidly in the geologic period known as the Cambrian.
Subject: phyla
Transcript: animal phyla just sort Of came into being. Animal life, the classification of it, Is looked at by taxonomists, and people interested in evolution And