The Cambrian Explosion Flashcards
When did the Cambrian Explosion occur?
Approx. 540 mya
What is the Cambrian explosion?
This refers to the sudden appearance (over a 10 million year period) of many different animals with a range of different body plans.
Where has much of the evidence come from?
Fossils which date back to when the Cambrian Explosion was said to have happened. It is thought that this was when animals developed hard bodies, making it easier for them to fossilise. A trilobite is a good example.
How do sedimentary fossils form?
When a fish dies, it falls on the rock bed. Over time, particles fall on the rock bad and the hard organic matter is replaced by inorganic minerals.
What could expose these sedimentary fossils?
Any movement in the earths crust.
What are trace fossils?
Footprints or other imprints of organisms.
What do scientists think indirectly lead to the Cambrian Explosion?
The evolution of a very simple eye 540 mya. This would mean that naturally harder shelled organisms would have been able to escape form these new ‘sighted’ predators. And when they reproduced, they passed on their hard shells and they became slightly harder. This is how it is thought to have developed.
What are the two most important senses possesed by a large number of animals?
Hearing and Sight
What is the human ear?
A complex structure which can detect sound waves and convert them into electrical impulses which can be deciphered
by the brain
What were the missing links in our evolutionary past?
- Ida
- Archaeopteryx
- Lucy
What is Archaeopteryx?
The fossil that is thought to be the missing link between dinosaurs are birds.
