Natural Selection

• What do offspring generally appear similar to?

  Their parents
• Are any two individuals identical?

  No
• What ability do organisms have regarding offspring?

  They can produce large numbers of offspring
• What is the general trend of population sizes in nature?

  They tend to remain fairly stable
• What did Darwin think about survival?

  There is a struggle to survive
• What happens to better adapted individuals according to Darwin?

  They survive and pass on their characteristics
• What can happen over time due to changes in species?

  New species may arise
• What causes variation within a species?

  Genetic differences caused by different alleles and random mutation
• Who is more likely to survive and reproduce?

  Organisms best adapted to a selection pressure
• What happens to alleles that confer successful adaptation?

  They are passed onto the offspring
• What is the result of advantageous alleles being passed on over generations?

  The frequency of individuals with the advantageous allele increases
• What can happen over many generations involving multiple alleles?

  This process can lead to the evolution of a new species
• What is natural selection?

  The selection of organisms best fitted to their environment
• What does natural selection rely on?

  Variation between individuals through mutation
• Who developed a similar theory to Darwin independently?

  Alfred Russel Wallace
• What did Alfred Russel Wallace do regarding his ideas?

  He wrote to Darwin about them
• What was the outcome of Wallace and Darwin's collaboration?

  They presented their ideas together to the scientific community
• What did Wallace's evidence do for Darwin's theory?

  It added support to Darwin's ideas
• How does artificial selection differ from natural selection?

  Artificial selection is driven by human choice
• What is speciation?

  The process of a new species forming from an old one
• What must happen for a new species to form?

  There must be reproductive barriers of some form
• What is allopatric speciation?

  Speciation in different geographical areas
• What is sympatric speciation?

  Speciation in the same geographical area