Zusammenfassung der Ressource
GCSE AQA Biology 1 Evolution
- Evolution
- The theory
of evolution
Anmerkungen:
- More than 3 billion years ago, life on Earth began as simple organisms from which all the more complex organisms evolved.
- Similarities/differences
allow classification
Anmerkungen:
- 1) Plants make their own food and are fixed to the ground
2) Animals move about and can't make their own food
3) Microorganisms are different to plants & animals
- Evolutionary and ecological relationships
- Evolutionary
Anmerkungen:
- * Species wich similar characteristics - similar genes because they share common ancestor (closely related), often look alike and live in similar habitat
* Genetically different species can look alike too
* Evolutionary trees show common ancestors/ relationships between organisms (more recent, more closely related)
- Ecological
Anmerkungen:
- * Organisms in same environment with similar characteristics - might be in competition
* Differences between organisms in same environment can show predator-prey relationships
- Natural Selection
- Charles Darwin's idea
- 1) Individuals within species show variation due to differences in genes
- 2) Individuals with characteristics that make them better adapted to environment
have better chance of survival - more likely to breed successfully
- 3) Useful genes more likely to
be passed on to next generation
- Mutations
- Mutation: Change in organism's DNA
- Mostly, mutations have no effect but can be
beneficial i.e. produce useful characteristic
- Beneficial mutation
more likely to be passed
on by natural selection
- Over time, beneficial mutation
will accumulate in a population
- Darwin's idea was very
controversial at the time...
- Wasn't enough evidence to
convince many scientists
Anmerkungen:
- Not many other studies had been done into how organisms change over time
- No good explanation of how
appeared or passed on - didn't
know about genes/mutations
- Went against
religious beliefs -
no need for God
- Lamarck
- Argued that if
characteristic was used a
lot it would become more
developed in its lifetime
- Believed
acquired
characteristics
would be passed
onto next
generation
- Evidence
- Lamarck's hypothesis rejected
- experiments didn't support
- Discovery of genetics supported Darwin's idea
Anmerkungen:
- Provided explanation of how organisms born with beneficial characteristics can pass them on (via their genes)