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16 Cards in this Set
- Front
- Back
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What are fossils and where are they found? |
Fossils are the preserved remains or traces of dead organisms. They are found in rocks. |
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Describe 3 ways fossils can be formed |
Hard body parts, such as bones and shells, which do not decay easily. Parts of organisms which have not decayed. For example, dead animals and plants can be preserved in amber (hardened tree resin), peat bogs, tar pits or in ice. Casts or impressions, such as foot prints or burrows. These become covered by layers of sediment, which eventually become rock. |
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True or false? Fossils of the simplest organisms are found in the oldest rocks, and fossils of more complex organisms in the newest rocks. This give support to the theory of evolution |
True |
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Name one of the few animals for which we have a fairly complete evolutionary record. |
The horse |
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Describe one adaptation that occurred during the evolutionary development of the horse. |
In the process its multi-toed feet, that were adapted for walking across the forest floor, evolved into single-toed hooves more suited for running over open country. |
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The horse evolved from what to what and over what period of time? |
Over 60 million years, the horse evolved from a dog-sized creature that lived in rainforests into an animal adapted to living on the plains and standing up to 2 metres high. |
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What is extinction |
When a species has failed to adapt to its environment and therefore does not continue to survive. |
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What are some of the factors that can cause a species to become extinct? |
New diseases New predators New, more successful competitors Changes to the environment over geological time - such as a change in climate A single catastrophic event - such as a massive volcanic eruption or a collision between an asteroid and the Earth Speciation |
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True or false? The fossil record shows that many species have become extinct since life on Earth began. |
True |
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Why can it be said that much extinction today occurs because of human activities? |
We compete with other living things for space, food and water, and we are very successful predators. |
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Describe how dodos became extinct. |
Dodos lived on Mauritius, an island in the Indian Ocean. The island was uninhabited and the birds had no natural predators.Then Mauritius was colonised by the Dutch in 1638. Dodos were hunted for food and easy to catch because they were not afraid of people. New competitors were brought onto the island, including pigs, cats and rats. These ate the dodos' eggs and their young. Within 80 years, the dodo was extinct. |
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Name 4 ways new species can develop |
Isolation Speciation Genetic variation Natural selection |
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What is isolation |
This is where two populations of a species become geographically separated allowing distinct changes in features to occur. |
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What is genetic variation? |
Where each population within a speicies has a wide range of alleles that control their characteristics |
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What is Natural Selection? |
Where the alleles which help an organism to survive are selected in each population |
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What is Speciation? |
Where the populations within a speicies become so different that successful interbreeding cannot happen anymore |
