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EVOLUTION. What is Evolution?. Evolution is the relative change in the characteristics of populations that occurs over successive generations. Diversity of Life. Diversity is the cornerstone of evolutionary biology Not all individuals of a species are exactly alike
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What is Evolution? • Evolution is the relative change in the characteristics of populationsthat occurs over successive generations
Diversity of Life • Diversity is the cornerstone of evolutionary biology • Not all individuals of a species are exactly alike • Differences between individuals are not always immediately visible • Diversity is important for the long term survival of a species
Biodiversity • Differences in characteristics between individuals may be: • Advantageous • Harmful • Neutral • Characteristic may not give an individual an advantage now, but may become critical for survival later if the environment changes
What controls the characteristics of individuals? • Genes!! • There are different versions of genes, known as alleles, in a population which is the basis of biodiversity. • Gene pool – total of all genes in a population
What is Evolution? • Evolution is • the relative change in the characteristics of populations that occurs over successive generations • any shift in the gene pool of a population • ratio of characteristics in a population change over successive generations
Who can evolve? • Individuals cannot evolve! • Individuals cannot change their genes. • Populations are the smallest unit that can evolve. • Populations can have a shift in their gene pool.
Why would populations evolve? • So that a population becomes better suited to its habitats. • Increased survival • Better chance of passing on characteristics to offspring. • Takes place over many generations.
How does a population evolve? • A shift in the gene pool so that a higher ratio of individuals have a particular adaptation. • Adaptation • a particular structure, physiology or behaviour that helps an organism survive and reproduce in a particular environment. • e.g. camouflage, superb sense of smell, bill shape
Example of a population that evolved:Peppered moths in England