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Evolution: Mechanisms

Explore the journey of Charles Darwin and the concept of natural selection that revolutionized our understanding of the natural world. Discover the mechanisms of evolution, from artificial selection to genetic variations, and see its impact on species over time. Learn about directional, stabilizing, and disruptive selection through real-life examples like antibiotic resistance and changes in allele frequencies. Gain a deeper understanding of the forces that shape the diversity of life on Earth.

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Evolution: Mechanisms

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  1. Evolution: Mechanisms To see where we might be going, we must understand where we have been Robert Tamarkin, 1993

  2. Natural Selection “Things exist either because they have recently come into existence or because they have qualities that made them unlikely to be destroyed in the past.” ― Richard Dawkins, The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design

  3. Charles Darwin • Not exactly a star student, but he revolutionized the scientific view of the natural world with his Theory of Natural Selection • Traveled on the Beagle where his journey began in 1831 for a 5 year voyage • The Beagle traveled from Europe to the Galapagos Islands then to Australia around the Cape of Good Hope and back to Europe

  4. Observations aboard the Beagle • Species vary globally a. Two similar species live in different areas of the world • Species vary locally • tortoises in the Galapagos islands • finches in the Galapagos island • Species vary overtime • Fossils of extinct animals looked like living animals

  5. Artificial Selection • Darwin also believed artificial selection supports the idea of evolution

  6. Artificial Selection • manipulated by humans to produce desirable traits. • With table buddy list three examples

  7. Natural Selection • Natural Selection: best suited to their environment survive and produce offspring • Fitness-How well an organism can survive • Adaptation- heritable characteristic

  8. Conditions Necessary for Natural Selection • Overpopulation-leads to completion for resources • Struggle for existence • Genetic Variations – size, form, speed, camouflage, strength, horns, etc. - • Survival of most fit- pass along characteristics to offspring.

  9. Types of Selection • Directional Selection • Stabalizing Selection • Disruptive Selection

  10. Directional Selection • Favoring one phenotype over others – Examples • Darker-colored Peppered Moths in England and the Industrial Revolution • mouse population- brown mice on the brown forest floor. • Antibiotic resistance in bacteria and the use of antibiotics • Pesticide resistance in insects

  11. Antibiotic Resistance • Antibiotic-Resistant Mycobacterium tuberculosis (TB) • Methicillin-Resistant Staphylococcus aureus (MRSA) • Vancomycin-Resistant Enterococci • (VRE) • Neisseria gonorrhoeae (Gonorrhea) • Clostridium difficile. • Gram-negative Bacteria.

  12. Allele Frequency Changes Peppered Moths During the Industrial Revolution in England Dark Color is Dominant Show a change over time in three generations following darkening of the trees

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