• The?allele frequencies?(within the gene pool) of a population can?change?over time due to processes such as natural selection
• When the?allele frequencies?of a population change?sufficiently?over time, the?characteristics?of the species will also change
• These changes can become so?great?that a?new species?forms
• This process is known as?evolution
• Evolution can be defined as:

The formation of new species from pre-existing species over time, as a result of changes to gene pools and allele frequencies from generation to generation

• The formation of new species via the process of evolution has resulted in a?great diversity of species?on planet Earth
  • Theoretically, at the origin of life on Earth, there would have been just?one?single species, to begin with
  • This species evolved into?separate species?(i.e. new species)
  • These species would then have?divided?again, each forming new species once again
  • Over millions of years, evolution has led to countless numbers of these?speciation?events, resulting in the millions of species now present on Earth

   

Evolutionary change over a long period of time has resulted in a great diversity of species

• The evolution of a new species can take a?very long time?and?many generations
• For organisms with a?short generation time?(such as bacteria), evolution can be observed far more?quickly