1 / 22

Devonian – the Age of Fish

Devonian – the Age of Fish. Dunkelosteus. Life on Land. First fossils of life on land Ordovician Period Possibly Middle Cambrian Why did Earth go so long without life on land? What prevented life from inhabiting the land?. Barriers to life on land. Dehydration

mrinal
Download Presentation

Devonian – the Age of Fish

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Devonian – the Age of Fish

  2. Dunkelosteus

  3. Life on Land • First fossils of life on land • Ordovician Period • Possibly Middle Cambrian • Why did Earth go so long without life on land? • What prevented life from inhabiting the land?

  4. Barriers to life on land • Dehydration • Osmoregulation: fresh vs. salt water • Reproductive dispersal • Support • Food supply • Temperature extremes • Exposure to UV and other radiation

  5. Life on Land • What do you suppose the earliest colonizers were like? • Where would they have lived? • What advantages might there be to living on the land?

  6. The Fossil Record: • Limited record of marine macrophytes – environmental requirements vs. preservation • Ordovician (Middle Cambrian?) - spores in marine sedimentary rocks • Spores indicate primitive, moss-like (non-vascular) plants

  7. First Vascular Land Plants • Conducting tissue • Stomates • No true roots – simple “hold fasts” • Appeared in Late Silurian to Early Devonian

  8. Cooksonia

  9. Rhynia

  10. Aglaophyton

  11. Asteroxylon

  12. Archaeopteris – Middle Devonian

  13. Archaeopteris/Callixylon

  14. Callixylon/Archaeopteris • The “Gilboa Forest” • First forest – Gilboa, NY • A new ecosystem • New conditions – adaptations to shade

  15. Zosterophyll – Middle Devonian

  16. What about Animal Life? • Rhyniaphytes show scars from arthropod (insect) predation • Why would arthropods be first to colonize land? • What about vertebrates?

  17. Eusthenopteron

  18. Eusthenopteron – a “missing link”

  19. Acanthostega – an early amphibian

  20. Latimeria – a modern crossopterygian

  21. Ichthyostega – First Amphibian(M. Dev.)

  22. Ichthyostega

More Related