Past Ecosystems Flashcards
How can Ice Core Drilling provide evidence for past changes in ecosystems?
Gas bubbles get trapped in the ice layers when the liquid is solidified. This gas remains chemically unchanged for the life of the ice bubble and contains information about the atmosphere at the time of solidification.
Outline the 4 general steps of fossilisation
- Rapid burial
- Fossilisation
- Petrification Method or Natural Moulds Method
- Uplift and weathering to expose fossils
Identify the 6 types of fossil preservation
- Mould
- Cast
- Permineralization
- Carbonisation
- Trace fossil
- Full preservation
Explain the 3 Conditions of Fossilisations
C1: Quick Burial
- prevents bones being eaten or scattered,
- slows down the process of decay
- keeps the organism parts generally intact
- most fossils are aquatic organisms, as quick burial is far more likely in water
C2: Suitable Body Parts
- Hard body parts survive fossilisation more easily than soft body parts
C3: Little geological disturbance
What is the Law of Superposition?
Younger sediments are layered above older layers.
How does Geological Evidence provide insight into the conditions of past ecosystems?
- Weathering of rocks by water, ice, wind and temperature changes provides evidence of environmental processes and conditions over time.
- Distinct mineral and chemical signatures in specific layers indicate past environments.
