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)