BIO 150 Lecture Notes - Lecture 20: Natural Selection, Mutation, Genetic Drift
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BIOLOGY 150- 3/26/2018: NOTES
• 7 to 15 billion species on the planet earth.
• 750 thousand insect species
• The size determines the class the organisms in diversity.
• 350 thousand species of beetles- diverse pattern,color,size
• 4 thousand species of mammals.
• Ecology- how organism interact with their environment- biotic or abiotic factors. - short term
• Evolution- how organisms have changed overtime- long-term changes.
• Evolution is concerned with the diversity of organism. How are they related? Evolution- what
adaptations allow organisms to do what they do?
• Evolution is “descent with modification”- it is a scientific theory.
• Evolution is both a pattern and a process-
1.Organisms are related by descent from common ancestors.- you look like your parents.
2. Organisms have changed overtime.
• Charles Darwin helped us see the root process of evolution.
Misconceptions of Evolution
50% of americans don’t know the definition of evolution
75% think it’s unproven and a theory.
• Theory- colloquial use- a guess
• In science its very well substantiated.
• Theories don’t become laws or facts.- they explain facts and laws.
• Scientific Explanations:
1. Be based on evidence from natural processes that can be observed and replicated,
2. Produce findings or hypothesis that can be tested and falsified.
3. Also must be open to debate and change.
• Ptolemy- scientific ideas are modified- Earth is center of the universe.
• Copernicus- sun is the center of the universe.- which was then approved 300 years later.
• Diseases arise from “bad air”- original theory
• Theories can take a really long time to change but can change years later.
• Scientific ideas change when new data confront old ideas and may take hundreds of years to be
• Is Evolution useful?
Can it make correct predictions?
▪ Organisms adapting to similar environments should evolve similar morphologies- also
called convergent evolution.
• Conversation- compare populations to one another.- we may look at badgers that live in
different locations in one place.- Milwaukee couty and ozakee county.
• Evidence for the pattern:
1.Organisms are related by descent from common ancestors:get from slide