Evidence of Evolution

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  • Created by: joshd
  • Created on: 17-03-14 13:02
What is a fossil?
A fossil is any trace of an animal or plant that lived long ago.
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How can fossils be formed from gradual replacement by minerals?
Things like teeth, shells and bones don't decay easily so can last ages when buried. The're eventually replaced by minerals, forming a rock-like substance shaped like the original hard part. The fossil stays distinct inside rock, until it's dug up.
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How can fossils be formed from casts and impressions?
Fossils can form where an organism's buried in soft material like clay. The clay hardens around it and the organism decays, leaving a cats of itself. Footprints can be pressed into these materials when soft, leaving an impression when it hardens.
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How can fossils be formed from preservation in paces where no decay happens?
As the conditions aren't suitable for microbes to work (e.g, in glaciers - too cold, in peat blogs - too acidic and in amber - no oxygen or moisture)
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What do fossils found in rock layers tell us. (1)
-What the creatures and plants looked like. -How long ago they existed. Generally, the deeper the rock, the older the fossil.
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What do fossils found in rock layers tell us. (2)
How they've evolved.From studying the similarities and differences between fossils in differently aged rocks, we can see how species have changed and developed over billions of years. You can then put together a family tree of a specie evolving.
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Why is the fossil record incomplete/have missing links?
-Very few dead plants/animals turn into fossils. Most decay away. - Some body plants,like soft tissue, tend to decay away completely. -There are fossils yet to be discovered that might help complete the picture.
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What is a PENTadactyl limb? Where can you see it?
A limb with five digits. You can see it in many species. (e.g, mammals, reptiles, amphibians)
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Compare th pentadactyl limb in each of the species. Give an example.
They have a similar bone structure, but usually a different function. E.g, a human's hand and a bat's wing are both pentadactyl limbs and look alike, but humans can't use theirs to fly.
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What does the similarity in bone structure provide?
It provides evidence that species with a pentadactyl limb have all evolved from a common ancestor (that had a pentadactyl limb). If they'd all evolved from different ancesotrs, it'd be highly unlikely that they'd share a similar bone structure.
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Other cards in this set

Card 2

Front

How can fossils be formed from gradual replacement by minerals?

Back

Things like teeth, shells and bones don't decay easily so can last ages when buried. The're eventually replaced by minerals, forming a rock-like substance shaped like the original hard part. The fossil stays distinct inside rock, until it's dug up.

Card 3

Front

How can fossils be formed from casts and impressions?

Back

Preview of the front of card 3

Card 4

Front

How can fossils be formed from preservation in paces where no decay happens?

Back

Preview of the front of card 4

Card 5

Front

What do fossils found in rock layers tell us. (1)

Back

Preview of the front of card 5
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