|
|
|
| Natural Selection gives individuals with an advantageous trait a better chance to reproduce and further their genetic line. | The second important basis of Darwin’s theory
is a process called Natural Selection. Selection is the most
important factor in evolution and provides the step of choosing the
organism best adapted to its environment. Darwin’s idea
was that hereditary traits provide individuals with a greater
chance of survival and reproduction. Darwin also proposed that there were different types of selection. The most controversial he proposed was sex selection. This states that females, perhaps having more practical bodies, have a greater advantage over males with their more awkward bodies, in some populations. An example of this type of selection is the male peacock. His tail is oversized and brightly coloured. The female, on the other hand, is plain coloured and small tailed. The male’s tail is used to attract the female for mating, though often it attracts predators also. His large tail also hinders his escape and often he ends up as dinner. Stabilising selection is always occurring in every
population. It kills off individuals with excessive
abnormalities or mutations. Many of these mutants die either
before birth or immediately after birth. Directional Selection is a process that increases the number of
individuals with an extreme observable characteristic. It
usually results in the gradual replacement of genes within a
genepool. (A genepool is made up of all the alleles of all the
genes of every individual in the species). Natural Selection gives individuals with an advantageous trait a
better chance to reproduce and further their genetic line.
Over time a stronger population is produced and unreliable
characteristics are lost. |
 |
|
 |
Your say: What is your opinion on evolution? |
 |
A look at plant and animal life especially adapted to its surroundings. |
 |
|
 |