classification- fossils

Soft tissues decay first, leaving behind…

Bones and teeth

What are the decomposer microbes?

Bacteria, fungi, detritus feeders

Mineralisation

1. ____________ (b, df, f) decay ____ tissue, leaning behind bones/____/shells.

2. Over many years _______ covers bones.

3. Over ________ of years, sediment and _________ builds up, FORCING _________ INTO DECAYING BONES.

4. This forms a ____-like fossil.

Microorganisms, soft, sediment, millions, pressure, minerals, rock

What is the first thing that happens in mineralisation?

Microorganisms such as bacteria, fungi, and detritus feeders decay soft tissue

In mineralisation, what builds up over millions of years, causing minerals to be forced into the decaying bones?

Pressure

Steps in mineralisation

1. Microorganisms decay soft tissue, leaving behind shells/bones/teeth.

2. Over many years sediment covers the bones.

3. Over millions of years, sediment and pressure builds up, forcing minerals into the decaying bones.

4. This forms a rock-like fossil

What causes the formation of cast fossils?

• an organism gets covered in soft rock (OVER MANY YEARS) and decays.

• The soft rock hardens, leaving behind a cast.

What causes the formation of ____ fossils?

• an organism gets ______ in soft rock (OVER _____ YEARS) and decays.

• The soft rock ______, leaving behind a ____.

Cast, covered, many, hardens, cast

Impression (simple description)

• footprint made in soft rock

• Soft rock hardens, leaving an impression

Preservation steps

1. Organism lands on tree.

2. Amber comes out of the tree as liquid and runs onto organism.

3. Amber solidifies.

4. Organism preserved in it.

Why does preservation via amber actually work?

• no oxygen can get to the organic matter for the microorganism to respire.

• And no water/ moisture present for decay.

What causes organisms to be preserved in ice?

its too cold for the enzymes in microbes to work/ decay

peat bogs are too _____ for microbes to decay whole humans

Acidic

Give reasons why we haven’t found all the fossils/why there aren’t many

• fossils underground- can’t dig up ground everywhere.

• Most organisms decay before fossils are formed.

• Tectonic plates move, destroying fossils beneath us.

• ________ plates move, destroying fossils beneath us.

Tectonic

• Most organisms _____ before fossils are formed.

Decay

Define fossils

The remains of organisms/their presence from many years ago which is found in rocks.

List the abiotic factors which affect microbes activity

Oxygen, moisture, temperature, pH

“Explain why the dodo became extinct [4]”

• dodo = large _________ bird.

• Humans ______ them.

• Humans introduced animals that ___ their ____.

• Humans destroyed ______ where their ______ were.

• Dodo couldn’t _____ quick enough to _____ the changes to their __________.

Flightless, Hunted, ate, eggs, forests, habitats, evolve, survive, environment