Flashcards in Chapter 8 Fossils Deck (41)
Naturally preserved evidence of life,
Whole body isn't fossilized, soft parts decay or get eaten. Hard parts buried in sediment slowly turn into rock
Hardened sediment that form around organism
Model of organism that forms when sediment fills a mold and hardens
What happens to an organisms stored energy when it dies?
Remains in organism cells; temperature and pressure layers above change dead organism into fossil fuels
Energy rich resources form from buried remains of organisms that were once alive
Petroleum & natural gas
Mainly form from organism that lived in the ocean
Form from decayed swamp plants piling up, decaying, and pressed into coal
Where are fossil fuels found
Since petroleum and natural gas form mainly from organisms that lived in the ocean, these fossil fuels are found where oceans used to be. Coal deposits found where swamps were
How old is the earth?
4.6 billion yrs old
Why is no rock on earths surface as old as the earth?
Rock is constantly being created and destroyed
Fossils of organisms that lived during a relatively short time span, are common, and found in many places
What does it mean when the same fossil types are found in widely separate places on Earth?
Land masses used to be in different places
Process by which continents have moved slowly from one position to another
How can you find out what kinds of ecosystems existed in certain areas in the past?
Look at fossils
How do scientists study organisms that are extinct?
Study their fossils
Shows how the kinds organisms that lived on Earth have changed over time
Period in which a large number of species become extinct relatively quickly
Do scientists know what caused a mass extinction?
No, they think any event greatly changing the environment can cause a mass extinction
How do some species avoid extinction?
Examples of fossils
Preserved remains, mold, cast, animal's burrow, animal's waste, footprint
Why are animals with hard parts parts more likely to become than animals with soft parts?
Soft parts decay or get eaten
Explain how fossil fuels form?
Animal dies but stored energy remains, overtime it's buried by sediment. Temperature & pressure slowly turn remains into fossil fuels
Why has natural gas use replaced coal use?
Burns cleaner producing less air pollution
What can be assumed about an area that is rich with petroleum?
It was an ocean
What can scientists learn from the fossil record?
How earth has changed over time
What do you know about different layers of rock that you see?
Oldest layers are on bottom, youngest on top
A place in CA where organisms are trapped in tar and become fossilized
When an organism dies, stored energy in its body is changed by heat and pressure into what?
Organism with these parts are more likely to form fossil fuels