Fossils ppt

FossilsFossils

What are Fossils?What are Fossils?

• Fossils are the remains or marks of plants Fossils are the remains or marks of plants and animals that lived a very long time and animals that lived a very long time ago. They are usually found in rock and ago. They are usually found in rock and stone.stone.

• Fossils are important because they tell us Fossils are important because they tell us a story about things that lived on the earth a story about things that lived on the earth before us. before us.

What Things Become Fossils?What Things Become Fossils?

• Animals and plants become fossils.Animals and plants become fossils.

• So do nests, eggs, footprints and even So do nests, eggs, footprints and even animal droppings! animal droppings!

How are Fossils Made?How are Fossils Made?

• Fossils are made from the hard parts of Fossils are made from the hard parts of plants and animals, such as:plants and animals, such as: - bark, seed cases, bones and teeth. - bark, seed cases, bones and teeth.

• These parts do not easily rot away after These parts do not easily rot away after plants and animals die.plants and animals die.

• Fossils take millions of Fossils take millions of years to form.years to form.

Turning to StoneTurning to Stone• For example:For example:

- A starfish dies.- A starfish dies.

- The soft parts of its body rot away quickly.- The soft parts of its body rot away quickly.

- The harder parts slowly get covered by mud.- The harder parts slowly get covered by mud.

- After millions of years, the starfish is deep in the ground. - After millions of years, the starfish is deep in the ground.

- The mud around it is crushed by the land on top and - The mud around it is crushed by the land on top and turned to stone. turned to stone.

- So are the remains of the starfish. - So are the remains of the starfish.

- Millions of years later, the stone gets worn away and the - Millions of years later, the stone gets worn away and the fossil can be seen. fossil can be seen.

How Fossils are FormedHow Fossils are Formed

From the SeaFrom the Sea

• The first creatures on the earth lived in the The first creatures on the earth lived in the sea.sea.

• Some sea creatures made good fossils Some sea creatures made good fossils because they had hard shells and hard because they had hard shells and hard bones. bones.

Horseshoe Crab FossilHorseshoe Crab Fossil

Trilobite FossilTrilobite Fossil

Fish FossilFish Fossil

PlantsPlants

• At first, there were only At first, there were only living things in the sea.living things in the sea.

• Slowly, over millions of Slowly, over millions of years, plants began to grow years, plants began to grow on the land.on the land.

• Some of these plants have Some of these plants have left fossils in the rock.left fossils in the rock.

Pine Cone FossilPine Cone Fossil

Animals Animals

• Animal fossils are often bones that have been turned to rock.  Sometimes Animal fossils are often bones that have been turned to rock.  Sometimes part of the flesh is preserved, but most of the time only skeletons remain.  part of the flesh is preserved, but most of the time only skeletons remain. 

• Because of this, it is more difficult to find fossils of invertebrates. Because of this, it is more difficult to find fossils of invertebrates. (Invertebrates are animals that don’t have bones.)(Invertebrates are animals that don’t have bones.)

• We have discovered several types of animal fossils: bones, skin, teeth, We have discovered several types of animal fossils: bones, skin, teeth, claws, eggs, nests, muscles, and organs. claws, eggs, nests, muscles, and organs.

• We have also found lots of fossils of footprints, which tell us how much We have also found lots of fossils of footprints, which tell us how much animals and dinosaurs weighed and how they might have walked.animals and dinosaurs weighed and how they might have walked.

When Did They Live?When Did They Live?• First Fish First Fish 570 million years ago. 570 million years ago.

• First plants on land First plants on land 440 million 440 million years ago.years ago.

• First insects and amphibians First insects and amphibians 400 400 million years ago.million years ago.

• First reptiles First reptiles 360 million years ago. 360 million years ago.

• First dinosaurs First dinosaurs 245 million years 245 million years ago.ago.

• First birds First birds 210 million years ago. 210 million years ago.