mechanism of evolution

• Mutation


  A change in the genetic makeup caused by environmental stressors. Expands diversity of organisms
• Geneflow


  The movement of genes from one population to another. When this happens, there is a tendency to increase the gene diversity in the populations
• Mechanisms of Evolutionary Changes

  • Mutation
  • Geneflow
  • Genetic drift
  • Natural selection
  • Nonrandom mating
• Genetic drift


  A change in the gene pool of a population due to chance
• Bottleneck effect


  • Takes place when population decreases due to various environmental factors such as fires, earthquakes and floods
• Founder effect


  • Happens when a small population of organisms separates from the larger group to invade a new area
• Nonrandom mating


  Increases the frequency of animals with desirable traits. It causes evolution because it intrudes the natural pool of gene variations
• Lamarck believed that organisms change during their lifetime to survive then pass these changes to their offspring
• Darwin believed in natural selection and struggle for existence. When an organism is fit and can adapt to its environment, it survives and has more chance to reproduce
• Natural Selecetion

  explains the difference in survival of individual and reproduce in a particular environment.
• what does the illustration show?

  genetic drift : founder effect

  
• what does the illustration show?

  gene flow

  
• what does the picture shows?

  mutation

  
• what does the picture shows?

  natural selection