bio final

• Evolution


  The process of how present-day organisms have descended from ancient ones
• Theory


  Well supported, testable explanation of a natural phenomenon
• Natural selection


  • Key factor for an organism to thrive and reproduce depends on how well suited the organism is to the environment
• Fitness


  The ability of an individual to survive and reproduce in a specific environment
• Phylogenetic Tree/Evolutionary Tree


  Diagram showing the evolutionary relationships among various biological species
• Dodo Bird


  • Found on the small island of Mauritius in the Indian Ocean, east of Madagascar
  • Non flying, overweight, pigeon like birds that were allegedly unfit to the environment because they could not fly
  • This made them easy prey
• Principle of common descent


  Species descend through generations with several changes over time
• Types of natural selection

  • Stabilizing
  • Directional
  • Diversifying
• Stabilizing natural selection


  Occurs when intermediate phenotypes are more likely to survive in the environment
• Directional natural selection


  Organisms with a phenotype that is well suited to their current environment are more likely to survive
• Diversifying natural selection


  Occurs when extreme phenotypes are more likely to adapt to the environment
• Camouflage


  Adaptation that helps an organism blend into its environment
• Artificial selection


  Individuals with desirable traits or characteristics are bred to increase the chances of having offspring with the same desirable traits
• Selective breeding


  Technique for artificial selection
• Non random mating


  Contributes to the population change from one generation to the next by the selected probability of mating with another individuals in the population
• Inbreeding


  When individuals are more likely to mate with their close relatives than with distant relatives
• Genetic drift


  Caused by unpredictable changes in allele frequencies due to small population sizes
• Population bottleneck


  Occurs when a sudden sharp decline in the population results in a drastic reduction of the total genetic diversity of the original population
• Founder effect


  Happens when there is a loss of genetic variation because of the migration of a small subgroup in a population
• Mutation


  The change in the structure of a gene caused by alterations in the DNA sequence of an organism
• Types of mutation

  • Substitution
  • Insertion
  • Deletion
• Substitution mutation


  Occurs when the genetic codon has one altered nitrogenous base
• Insertion mutation


  Characterized by the addition of an extra set of base pairs to the genetic material
• Deletion mutation


  Occurs when a set of base pairs in the genetic material is omitted
• Neutral mutation


  Affects the organism's phenotype but has no impact on its survival or reproduction
• Beneficial mutation


  Affects the phenotype of organisms, resulting in an increase in their chances of survival or reproduction
• Recombination


  This process naturally occurs during the crossing over stage in meiosis, where there is an exchange of DNA between homologous chromosomes
• Gene flow (migration)


  Happens when there is transfer of genes from the gene pool of one population to another
• Emigration


  Happens when organisms leave their habitat
• Immigration


  Happens when organisms enter another habitat and live in it
• Charles Darwin was born in England on 12 February 1809. In 1831, Darwin went aboard the H.M.S. Beagle in its voyage around the world.
• Jean-Baptiste Lamarck was a French naturalist, and was one of the first scientists to recognize that living things have changed over time. In 1809, Lamarck published his theory of how organisms changed over time.
• Theory of use and disuse


  According to the theory, organisms could alter the size, shape, or structure of particular body parts or organs by continuously using them in new ways
• Theory of inheritance of acquired characteristics


  States that organisms inherited their traits from their parents, and that they may also pass them on to the next generation of offspring
• Evidence of evolution


  • Biogeography
  • Fossil record
  • Homology
  • Embryology
  • DNA/Protein sequence
• Biogeography


  The distribution of organisms in an environment can be used as an important tool for explaining evolution
• Fossil record


  A fossil contains preserved remains or evidence of ancient organisms, and shows how different groups of organisms have changed over time
• Homology


  Evidence of evolution can be found by studying and comparing certain body parts of different animals, which may have different mature forms but came from the same set of embryonic tissues
• Embryology


  Different organisms have similar structures during their early embryological development, and the shared embryological development is responsible for the similar growth of their homologous structures
• DNA/Protein sequence


  Similarities in DNA sequences among organisms indicate their close relation with one another, and studying DNA and other molecular evidence makes it easier to trace the evolutionary history of organisms