3. 1. 4 - New evidence for evolution

Question 1

how can DNA profiling produce new evidence for evolution?

Answer 1

• can produce an insight into evolutionary links
  (e. g now DNA can be extracted from suitable fossils under 100 000 years old)
• the more mutations there are in DNA from two individuals, the longer time since they had a common ancestor

Question 2

what is the problem with this?

Answer 2

• DNA starts to degrade immediately after death
• fragments can survive for 50 000 - 100 000 years
• the rate at which different parts of DNA mutates can vary
• the evidence needs to be viewed with caution

Question 3

Apart from human DNA, how else can you look into human evolution?

Answer 3

Parasitic lice: head lice, pubic lice and body lice
- head and body lice are related to chimpanzee lice
- common ancestors of humans and chimps diverged about 6 million years ago –> head lice species diverged at the same time
- pubic lice more closely linked gorilla louse –> human and gorilla ancestors diverged about 6 million years ago
but pubic and gorilla lice only only diverged 3 millions years ago
- humans lost body hair by then

Question 4

what is the role of the scientific community?

Answer 4

• to peer review submitted articles by a number of experts to see if it is reliable for publishing
• it helps to promote the development of new techniques
• provides opportunity to challenge the validity of results
• it facilitates the exchange of ideas, data and techniques between scientists from all over the world in their specific field of study