Evolution & Natural Selection. Evolution. Means “change.” In a narrower sense referring to organisms, means a permanent change occurring in a species over generations. Can evolution be a fact?. Forms that evolution may take. Extinction. Artificial selection.
Natural Selection works with Variation.
Variation refers to:
In the case of natural selection, the force of selection stems from the environment:
The environment is all-encompassing, amounting to anything that can potentially kill an individual from the moment it is conceived, e.g. mom’s drug or alcohol use, diet, etc. while pregnant.
Sexual selection acts upon (and explains) secondary sexual characteristics.
Secondary sexual characteristics are those physical traits which differentiate males from females, excluding the sexual organs (the primary sexual characteristics).
Natural selection cannot work without failure!!!!!
What would happen to a population if all organisms lived and mated?
One of the most important concepts in the theory of natural selection is Fitness.
Definition of fitness: differential reproductive success. Reproduction must result in viable offspring for an individual to be deemed fit.
Famous people with 0 fitness:
W.A. Mozart., L. van Beethoven, Johannes Brahms, George Washington, Abraham Lincoln, Oprah Winfrey.
The Clintons, Anna Nicole Smith
Bottom line: for an individual to have an evolutionary impact, genes must be passed to the next generation and beyond.
Was Darwin fit?