H1 This is up top

Part 3 - H2 Heading on darker??

Evolution is the change in the heritable characteristics of biological populations over successive generations. It occurs when evolutionary processes such as genetic drift and natural selection act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. The process of evolution has given rise to biodiversity at every level of biological organisation.

The scientific theory of evolution by natural selection was conceived independently by two British naturalists, Charles Darwin and Alfred Russel Wallace, in the mid-19th century as an explanation for why organisms are adapted to their physical and biological environments. The theory was first set out in detail in Darwin's book On the Origin of Species. Evolution by natural selection is established by observable facts about living organisms: (1) more offspring are often produced than can possibly survive; (2) traits vary among individuals with respect to their morphology, physiology, and behaviour; (3) different traits confer different rates of survival and reproduction (differential fitness); and (4) traits can be passed from generation to generation (heritability of fitness). In successive generations, members of a population are therefore more likely to be replaced by the offspring of parents with favourable characteristics for that environment.

In the early 20th century, competing ideas of evolution were refuted and evolution was combined with Mendelian inheritance and population genetics to give rise to modern evolutionary theory. In this synthesis the basis for heredity is in DNA molecules that pass information from generation to generation. The processes that change DNA in a population include natural selection, genetic drift, mutation, and gene flow.

H3 Heading

• First level bullet point
• Another first level item
  • Second level sub-bullet
  • Another sub-bullet with more content
  • Third sub-bullet item
    • Third level nested item
    • Another deeply nested item
• Final first level item

H4 Heading

1. First numbered item
2. Second numbered item with sub-items
   1. Sub-item one
   2. Sub-item two
   3. Sub-item three with nested list
      1. Deeply nested item
      2. Another deep item
3. Third numbered item
4. Final numbered item

Button 01 Button 02