Skip to main content

Effects of Past Global Change on Life (1995) / Chapter Skim
Currently Skimming:


Pages 29-29

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 29...
... We can reject the Cloud hypothesis; we can suggest that oxygen levels actually decreased during the Meso- or early Neoproterozoic; or we can suggest that the first macroscopic animals did not possess well developed circulatory systems and, therefore, required oxygen levels substantially greater than l5~o PAL. It is certainly premature to choose the first option, and we know little about the history of atmospheric oxygen between 1900 and 600 Ma or the internal architecture of Ediacaran animals.
Read the entire page →

Key Terms

  • macroscopic animals
  • late proterozoic
  • earth history


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
    More information on Chapter Skim is available.