answersLogoWhite

0

The Cambrian Explosion, a period between about 540 and 530 million years ago when many major animal groups appeared in the fossil record. This is when animals first developed hard shells and skeletons, so they became much more easily fossilised.

Nobody is quite sure what caused the Cambrian Explosion, but increased oxygen levels in the air after the melting of a huge ice age around 600 million years ago may have led to an increase in the size of animals in the oceans; in turn they developed skeletons and shells to support their larger bodies. The evolution of predators may have inspired prey animals to develop shells, as well.

We do have fossils before the Cambrian Explosion, but these are simple, soft-bodied, small and rare, so the origins of animals are still shrouded in mystery.

User Avatar

Wiki User

14y ago

What else can I help you with?

Related Questions

When did modern humans appear on earth according to fossil records?

According to the fossil records, the modern humans did appear on earth more than 130,000 years ago.


How many years did dinosaurs roam the earth according to fossil record?

I don't know by fossil record but I have a book called walking with the dinosaurs and it said 220 million years ago


In general the first mammals of any group to appear in the fossil record?

resembled dogs and cats


Approximately how long have Homo sapiens been on earth according to the fossil recordAsk us anything?

Homo sapiens have been on Earth for approximately 300,000 years, based on evidence from the fossil record.


What is a record fossil?

A fossil record is a historical sequence of life indicated by fossils found in layers of Earth's crust.


How long have homo sapiens been on earth according to fossil record?

Homo sapiens have been on Earth for approximately 300,000 years according to the fossil record. This time frame is based on archaeological and anthropological evidence of early human remains found in different regions around the world.


What does the fossil record about the evolution of life on Earth?

years


What does the rock and fossil record represents?

The history of the Earth and the history of life on Earth.


What does the fossil record reveal about the evolution of the life on Earth?

years


What the fossil record reveal about the evolution of life on earth?

years


What does the fossil record reveal about the evolution life on Earth?

years


The fossil record indicates that Earth has experienced?

5 mass extinctions