Fossil Evidence for Evolution

What is a fossil? A fossil is a physical

remain of an ancient organism.

The study of fossils is called paleontology.

Fossils of a fish and a wasp.

How are fossils made? The organism dies and is

covered by mud, dirt or rock.

The body starts to decay, caused by bacteria metabolizing the organic material.

If few bacteria are present, mineral replacement occurs and eventually the organism becomes rock.

Many times there are too many bacteria and the organism decays before fossilization can occur.

Because of this, the fossil record is far from complete.

Soft Tissue Fossils Soft tissue can sometimes

make a fossil record if it leaves an impression in mud that hardens and is preserved

Soft tissue fossils can also happen in ice or amber, where the actual organism was preserved

For example, insects in amber or wooly mammoth in Arctic ice

Extinction Extinction is when the last

living member of a species dies out

Extinctions have been happening at a much faster rate

This is due to the increase in human population-hunters, decrease of habitat

ie; passenger pigeon

A passenger pigeon.

How do fossils provide evidence for Evolution?

Fossils provide physical records of organisms that are not alive today.

These are very helpful for scientists to study body structures of ancient organisms and relate them to modern species.

Fossils also are evidence of the rate of evolutionary change.

Fossils in intermediate stages between species and their ancestors give clear evidence of evolution.

Fossils of feathered dinosaurs found in China reveal some evolutionary stages between dinosaurs and birds.