Variation and evolution
Key Words
Species - class of plants or animals whose members have the same main characteristics and are able to breed with each other.
Variation - differences in within-species eg. In humans, hair colour or eye colour etc.
Genetic Variation - caused by different genes from the parents.
Environmental variation - differences caused by the conditions that organisms live and grow in.
Mutations - random changes in an organism's DNA. These can sometimes be inherited.
Charles Darwin - came up with the Theory of Evolution:
All of today's species have evolved from simple life forms that first started to develop over three billion years ago.
Phenotypic variation - wide variation in a species characteristics.
'Survival of the fittest' - organisms that are more likely to survive because of their suitable characteristics for the environment they live in.
Speciation - populations of the same species change enough to become reproductively isolated.
Reproductively isolated - species can't interbreed to produce fertile offspring.
Extinction - when no individuals of a species remain.
Fossils - remains of plants and animals found in rocks. They can be formed in three ways:
- Gradual replacement - the remains replaced by minerals while buried. Fossil is distinct inside the rock.
- Casts and impressions - soft remains decay leaving a cast or impression.
- Preservation - no decay takes place it's preserved in amber, glaciers or peat bogs.
Classification - organising living organisms into groups.
Linnaean system - created by Carl Linnaeus, it groups living things according to their characteristics and the structures that make them up.
Also see Reproduction, Genetics
Links for Learning
[wp-svg-icons icon="screen" wrap="span"] Websites [wp-svg-icons icon="film" wrap="span"] Videos [wp-svg-icons icon="dice" wrap="span"] Games [wp-svg-icons icon="signup" wrap="span"] Quizzes
[wp-svg-icons icon="screen" wrap="span"] Bitesize: Evolution
[wp-svg-icons icon="screen" wrap="span"] Revision Science: Evolution & Extinction
[wp-svg-icons icon="screen" wrap="span"] Live Science: Darwin's Theory of Evolution
[wp-svg-icons icon="screen" wrap="span"] Bitesize: Variation
[wp-svg-icons icon="screen" wrap="span"] Revision World: Variation & Mutation
[wp-svg-icons icon="screen" wrap="span"] Bitesize: Evidence for evolution - rock fossils
[wp-svg-icons icon="screen" wrap="span"] Bitesize: Linnaean system of classification
[wp-svg-icons icon="screen" wrap="span"] Bitesize: Classification of animals
[wp-svg-icons icon="screen" wrap="span"] Bitesize: Variation test
[wp-svg-icons icon="screen" wrap="span"] Bitesize: Evolution test
[wp-svg-icons icon="screen" wrap="span"] Bitesize: Classification of living organisms test
Find out what kind of learner you are and the best revision techniques for you.
Visit our Revision Tips page for more.
Biology Revision Buddy Shop
For even more products visit our full Biology Shop
[supsystic-gallery id=5]