Mass Extinction Evolution

During ordinary times, it is natural for some species to die off and become extinct. After they die, their homes, called ecological niches, become vacant. Species have a natural tendency to spread out and quickly take over any vacant ecological niches. Then they slowly adapt to their new homes. Fossil records show how living creatures grow new body parts or change a particular behavior in order to fit into their new environment. This adaptation usually takes place over thousands of years, and species

TRICERATOPS

The Triceratops traveled in enormous herds, like today's elephants do. The largest adults formed the outside of the herd. They protected their young by surrounding them. These parenting abilities show that some dinosaurs formed strong social communities. This may help explain why dinosaurs survived and thrived for 150 million years.

become more diverse over this long period of time. Those species that do not adapt eventually perish.

However, after a mass extinction, millions of ecological niches are suddenly left empty. The survivors of mass extinction rapidly begin to fill these empty niches. This allows many more species to adapt to new environments than under normal circumstances. Scientists think this is the reason behind the huge explosion of life's diversity after extinction. Life quickly evolves to fill every single empty nook and cranny of the world.

Billions of species have lived and died since life began on Earth. Fossil records show that a species never repeats itself.

Fossilized human skeletons were discovered in caves in southern France. Dating of the fossils tells us that prehistoric humans lived there about 2 million years ago in the Late Tertiary Period.

Think of the biodiversity the world has witnessed! It is estimated that there are 10 million different species alive today.

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