Evolution - IntroductionBiological Changes over time

Principles of Evolution Populations of living things contain

variation of individuals Mutations can cause further variation in

population Mutations can be beneficial, harmful or

neutral If mutation is beneficial can alter gene

pool of population

Artificial Selection – a case of synthetic evolution Domestication has forced changes in

organisms to best suit human needs We have selected certain traits over

others causing a change in phenotype of organisms

Referred to as Artificial Selection

Example of artificial selection

Broccoli A human engineered

vegetable with origins to sea cabbage (brassica oleracea)

Selection of Brassica Agriculture caused ancient farmers

(2000 y.a) to select brassica with the largest most desired features

Broccoli was created by selecting plants with the largest stems and flowers and allowing them to breed

Over time stems and flowers became very large and pronounced

Other B. oleracea offshoots

Kale

Cabbage

Kohlrabi

Artificial Selection can be powerful!

Science of Breeding Hypothesis: Breeding selected

individuals with certain favoured traits will result in the favoured traits becoming more prevalent and more pronounced

Procedure:1. Choose a useful species that can be bred in captivity.2. Breed a large number of individuals.3. Choose a trait that you wish to favour, such as large size, a particular colour, or sweetness.4. Identify individuals that exhibit the favoured trait most strongly.5. Breed only these individuals to produce the next generation of individuals.6. Repeat Steps 4 and 5 over many generations

Concerns Selection can lead to loss of genes Can make organisms susceptible to

disease Some traits can be linked to others that

could be detrimental to the population(ie; pure white colour in cats is linked to deafness)