Welcome to biology-online.org! Please login to access all site features. Create an account.
Log me on automatically each visit
Digging into the past and investigating the origins of life. Find out …
Tutorials » The Origins of Life » Dinosaur Extinction
No one truly knows how the dinosaurs became extinct, but the fact is they disappeared and a whole host of ecological niches were made available to other organisms, who could harness the resources of these niches due to the absence of competition (and predation) by dinosaurs.
The dinosaurs disappeared around 65 million years ago, with many other land dwelling organisms also dying out around this time. Regardless of what killed off the dinosaurs, it was comprehensive. The general consensus is that a major geological event killed off many of the land dwelling organisms, particularly the larger ones.
This would have caused an overall drop of biomass on land, and therefore 'less food to go round' all the organisms that occupied dry land. Also, many food chain relationships would have been disrupted, causing a gradual breakdown of populations in the long term, sometimes leading to extinction, essentially survival of the fittest.
Insects, due to their size, were adaptable and already diverse, meaning that at least their short term survival and close relationship with plants (at the bottom of any food chain) was secured
Marine life was still plentiful, and diversifying, while mammals were emerging to be the next dominant force on plant Earth.
Birds were also diversifying, and taking advantage of their proportionately larger body in comparison to insects, alongside their ability to fly.
On the other hand mammals were specialising on land, and trees, which we further investigate on the next page of the timeline below...
Next Tutorial PageThe Ancestors of Mammals
rating: 4.07 from 1614 votes | updated on: 1 Jan 2000 | views: 852212 |
share this tutorial | email to friends
suggest a revision
print this page
print the whole tutorial
© Biology-Online.org. All Rights Reserved. Register | Login | About Us | Contact Us | Link to Us | Disclaimer & Privacy