Thi Thing

Section One: Research

  a) Using your own words briefly outline the Darwin/Wallace Theory of Evolution by Natural Selection and Isolation.

  The theory of evolution by natural selection and isolation was proposed jointly by Charles Darwin and Alfred Russel Wallace in 1858 to account for observations made on their extensive voyages.
  The theory outlines that characteristics favourable to the reproduction and survival an organism in their environment will be selected for, and over time, new species will appear in response to environmental changes.

  Some organisms possess characteristics more suited to the environment than others. These organisms are therefore more likely to survive and more likely to reproduce passing their characteristics onto their offspring. Gradually, over many generations, new organisms better adapted to the environment will evolve. The theory of natural selection is simply “the survival of the fittest” with fitness not only referring to being healthy, but to being well adapted to the environment but also to the reproductive capacity of the individual. The core of Darwin's theory is natural selection, a process that occurs over successive generations and is defined as the differential reproduction of genotypes.

  The theory is based on five important factors:

  1. All organisms produce more offspring than can actually survive.
  2. Each organism must face a constant struggle for survival.
  3. The individuals of a given species have varying characteristics as a result of sexual reproduction.
  4. Those individuals with characteristics best suited to the selective pressures of the environment will survive and reproduce.
  5. Over many generations these characteristics will increase in the population.
The Process of Natural Selection

  A new species will develop if members of the same species are subjected to different environmental pressures. This requires some form of isolation. The commonest...