- Ex. Giraffes stretching for branches generation after generation would lead to them having longer necks.
DARWIN'S theory of evolution was that all varieties of life descended from shared (in common) ancestors. This means complex creatures naturally evolved from simpler ancestors, over time. In other words more agile or better fit organisms tend to survive and to pass on their superior characteristics to subsequent generations.
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Natural Selection is the process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution.
Examples:
1. In a habitat there are green bugs and brown bugs. The birds prefer the taste of the green bugs, so soon there are many brown bugs and few green bugs. The brown bugs reproduce and make more brown bugs and eventually there are no more green bugs.
2. A species of rats live in a certain type of tree with the branches evenly spaced. Smaller rats could not reach from branch to branch and larger rats would break the branches and fall. Soon, all rats were just the right size for the tree branches.
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During and since Darwin's time, people have been looking for and studying evidence in nature that teaches them more about evolution. Some types of evidence such as fossils and similarities between related living organisms, were used by Darwin to develop his theory of natural selection, and are still used today. Others, such as DNA testing, were not available in Darwin's time, but are used by scientists today to learn more about evolution.
Evidence examples?
- Ancient Organism remains
- Fossil layers
- Similarities among organisms alive today
- Similarities in DNA
- Similarities of Embryos
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