5073928
Description
Flashcards by francesca graham, updated more than 1 year ago
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Created by francesca graham
over 8 years ago
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| Question | Answer |
| What are fossils? | Remains of plants and animals |
| What are the 3 forms of fossils? | 1) gradual replacement by minerals 2) Casts and impressions 3) Preservation |
| Explain how casts and impressions happen. | When an organism is buried in a soft material like clay. When the clay hardens around the organism it decays leaving a cast of itself |
| Name 3 natural things that an organism can be preserved in | 1) Amber 2) Glaciers 3) Peat bogs |
| Why doesn't organisms decay in amber? | Because there isn't and oxygen or moisture present do decay microbes can't survive |
| Why don't organisms decay in glaciers? | Because it's too cold for decay microbes to survive |
| Why don't organisms decay in Peat bogs? | Because it's too acidic for decay microbes |
| Why are Peat bogs are called Peat bogs? | Because a fully preserved man they named Peat Marsh was found in a bog |
| What do fossils show us? | How many of today's species have evolved over millions of years |
| Give 2 scientific hypothesis of how life on Earth started | 1) Primordial swamp (or under the sea) 2) Organic matter brought to Earth by comets that became more complex |
| Why can't hypothesis about how life on Earth started be supported or disproved? | Because there is a lack of valid reliable evidence |
| Give 2 reasons why there is a lack of evidence for how Life on Earth started | 1) Because many scientists believe that the first life forms were soft bodied so they would have decayed completely and quickly 2) Fossils that could have formed millions of years ago may have been destroyed by geological activity |
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