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

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

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

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

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

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

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

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.

Types of Selection Directional Selection Stabalizing Selection Disruptive Selection

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

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

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