Theory of Evolution

  • Variation exists within genes of every population or species as a result of random mutation
  • In a particular environment some individuals of a population are better suited to survive and to have more offspring
  • Over generations the traits that make certain that certain individuals of a population ale to survive and reproduce tend to increase in that population
  • Evidence from fossils and many other sources indicate that living species evolved from species that no longer exist
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Evolution is the change in the inherited traits of a population of organisms through successive generationsThe main cause of variation is mutation, which changes the sequence of a gene. Altered genes, or alleles, are then inherited by offspring.Over many generations, mutations produce successive, small, random changes in traits, which are then filtered by natural selection and the beneficial changes retained. This adjusts traits so they become suited to an organism's environment: these adjustments are called adaptations.
Evolution theorizes that all organisms evolved from a common ancestor, this causes all organisms to have the same type of genetic material, DNA
Fossile sprovide most insight on the history of evolution, through the finding of fossils and the use of radioactive isotopes, scientists have agree on three basic points

  • The earth is approximately 4.5 billion years old
  • Over time organisms of increasing complexity appeared on earth
  • All organisms living today evolved from earlier life forms

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1. Which is a result of natural selection?
A. Changes in the environment
B. More offspring than can survive
C. Changes in the genes of a population
D. Genetically identical individuals

Some large snakes such as pythons have small internal leg bones, What are these bones examples of?
A. Fossil organs
B. Vestigial structures
C. Polyploidy
D. Extinction

3. Do you believe in evolution, why or why not?

4. What came first, the chicken or the egg?