Zusammenfassung der Ressource
AQA GCSE Biology
B1.7 Evolution
- Lamarck
- Suggested a theory called 'the inheritance of acquired characteristics'
- Theory stated that characteristics which develop during
an organism's lifetime can be passed on to the next
generation
- People found this difficult to believe
- Darwin
- Suggested the theory of 'natural selection'
- Theory stated that small changes in an organism
took place over a very long time and all organisms
in a species vary and therefore some are more
likely to survive. Those that are best adapted breed
and pass on characteristics
- The theory of natural selection was only very gradually accepted as:
- It challenged the theory of creationism
- Insufficient evidence at the time
- The mechanism of variation and inheritance
was not known until 50 years later
- Natural Selection
- Evolution occurs via natural selection
- Individuals in a specific species may show a
wide range of variation due to differences
and mutations in their genes
- Individuals with the characteristics best suited to the
environment in which they live are more likely to survive
- They are therefore more likley to breed
successfully and pass on the genes to their
offspring
- Where new forms of a gene
result from mutation, there
may be a rapid change in a
species if the environment
changes.
- Classification
- Studying the similarities and differences between
organisms allow us to classify organisms into
animals, plants and microorganisms, and helps us
to understand evolutionary and ecological
relationships
- Models allow us to suggest relationships between organisms.
- Evolutionary trees are an example of these.