Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. What evidence is there now to support Darwin'stheory of evolution?
   • We have now unearthed fossils which we have been able to sequence the genomes of as well aslook at similar characteristics which have developed over time in a range of fossilised remains. Testing of antibiotic resistant bacteria has also shown rapid evolution within the species in order to help them survive treatment with antibiotics.
2. What are fossils?
   • Fossils are the remains of organisms from millions of years ago, which are found in rocks.
3. How can fossils be formed?
   • Fossils may be formed: ? from parts of organisms that have not decayed because one or more of the conditions needed for decay are absent ? when parts of the organism are replaced by minerals as they decay ? as preserved traces of organisms, such as footprints, burrows and rootlet traces.
4. Why is there little evidence of very early life forms?
   • Many early forms of life were soft-bodied, which means that they have left few traces behind.
5. Why can we not be certain of how life on earthformed even from hard bodied organisms?
   • What traces there were have been mainly destroyed by geological activity. This is why scientists cannot be certain about how life began on Earth.
6. What is the main thing we can learn from fossils?
   • We can learn from fossils how much or how little different organisms have changed as life developed on Earth.
7. Why is the fossil record described as incomplete?
   • Due to the constantly changing earth many fossils have been lost to us due to geographical changes suchas volcanoes and earth quakes. Some fossils have simply yet to be found and others still lie beneath the oceans.
8. How do scientific methods and theories develop over time?
   • Scientists constantly refine scientific methods by replicating them and finding and fixing flaws through new technology or knowledge. Theories are also challenged and evidence gathered regularly.
9. What is extinction?
   • Extinction occurs when there are remaining individuals or a species still alive.
10. What are some of the factors that contribute to extinction?
    • Extinctions can occur when: changes to the environment occur, such as a change in climate, new diseases, new predators and new competitors.