BY2 - Evolution & Classification (2)
- Created by: beth-marie2511
- Created on: 31-05-16 12:15
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- Evolution & Classification
- Evidence of Common Ancestry
- Closely related species are recognised by their similar morphology.
- E.G. Homologous Structures
- Structures that have a common origin but serve a different function.
- Pentadactyl Limb in vertebrates
- Humans
- Hand
- Used for grasping and holding things
- Cats
- Legs
- Used as support for jumping and walking etc.
- Whales
- Flipper
- Used for movement in water - swimming
- Bats
- Wing
- Used for flight
- Humans
- E.G. Homologous Structures
- Biochemical Methods
- Measure between the proportion of genes or proteins shared between different species to determine relatedness.
- Proteins tend to be displayed as bands on an electro-phoresis gel.
- Biochemical methods can reduce the mistakes made in classification due to convergent evolution.
- The tendency of unrelated organisms to develop / acquire similar structures.
- Closely related species are recognised by their similar morphology.
- Analogous Structures
- Structures that have the same function but a different origin.
- E.G. The wings of a bird and an insect are not an indication that they are related.
- Convergent Evolution
- The process by which two lines of evolutionary development brings about superficially similar creatures.
- When different groups of organisms are subjected to the same environmental selection pressures they tend to evolve similar design features.
- Biodiversity
- A measure of the number of species on the planet.
- Rainforests and coral reefs are the most diverse habitats on the planet.
- Species
- A group of organisms that can interbreed and produce fertile offspring.
- Extinction
- The loss of a species.
- Evolutionary history shows that biodiversity has gone through several 'bottlenecks' called mass extinctions.
- Followed by the radiations of new species.
- Causes
- Deforestation
- Construction
- Development of industry
- Evolution
- The process by which new species are formed from pre-existing ones over very long periods of time.
- Natural selection drives the evolution of new species .
- Due to selective advantages developing and being inherited by the offspring and then passed on to new generations.
- Development of a new species from a common introduced into the environment
- Adaptive Radiation
- Evidence of Common Ancestry
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