Comment: 03:02 - 03:55 (00:53)
Source: Annenberg/CPB Resources - Earth Revealed - 11. Evolution Through Time
Keywords: "Dee Trent", fossil, erosion, "plate tectonics", "sedimentary rock", "terrestrial life", vertebrate, weathering, predation, scavenging
|
Our transcription: That fossils exist at all is startling considering the vigorous processes of erosion and plate tectonics acting on Earth's surface.
The preservation of fossils is probably best in the ocean where you have a super abundance of organisms.
So that when you have many millions of little critters that can fall on the sea floor, many tens or even hundreds or thousands may be preserved.
So probably our best fossil record comes from marine sedimentary rocks when the organisms are small and the chances for preservation are best.
Terrestrial life, however, is not as dense as it is in the ocean, and because of the chemical weathering and predation, scavenging, and so on by other animals, the record, especially of vertebrates, is not really as complete as would be desirable.
|
Geology School Keywords
|
