Old and new species key points
- Created by: millera
- Created on: 23-03-14 11:45
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- old and new species
- Origins of life on earth
- Fossils are the remains of organisms from many years ago that are found in rocks
- Fossils may be formed in different ways
- Fossils give us information about organisms that lived millions of years ago
- It is very difficult for scientists to know exactly how life on earth began because there is little evidence
- Exploring fossil evidence
- Causes of extinction
- New predators
- New diseases
- New or more successful competitors
- What we learn from fossils
- How much or how little organisms have changes
- Causes of extinction
- Extinction
- Caused by
- Environmental change over geological time
- Mass extinction
- Caused by
- Single catastrophic events
- e.g Volcanoes or asteroid strikes
- Single catastrophic events
- Caused by
- Caused by
- Isolation and evolution of new species
- New species arise when two populations become isolated
- Populations become isolated when they are separated geographically
- e.g. on Islands
- There are natural cycles linked to environmental change when species from and when species die out
- In an isolated population alleles are selected that increase successful breeding in the new envrionment.
- Speciation
- Takes place when an isolated population becomes so different from the original population that the successful interbreeding can no longer take place
- Origins of life on earth
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