2 What is a Theory? Everyday Language Scientific Language Hunch; Guess Created after years of experiments and observationBased on testable evidenceStood the test of timeBased on gravitational theory, what do you think would happen if I dropped a pen?
4 Jean Baptiste de Lamarck Acquired Inheritance: Early theory where changes acquired over a lifetime could be passed to offspringEx: Evolution of the giraffe neckShort neck ancestors stretched their necks to reach leavesStretched neck was passed to offspringWhy this is wrong: Only traits linked to DNA can be passed to offspring
5 Silly Example of Acquired Inheritance If Jacob has children in the future, how many arms will they have?Jacob lost his left armJacob is in a car crashMeet Jacob
6 Charles Darwin Observations: Organisms have variations based on their environmentVariations provide advantagesNatural Selection: Process where organisms with favorable traits survive and reproduce1859: Published The Origin of SpeciesNotch in shellSurvive in areas with higher vegetationNo notch in shellSurvive in areas with ground vegetationThose with short necks died. Those with longer necks survived and had babies.So how did giraffes get a long neck?
8 Adaptation vs. Variation Variation: Inherited traits that make an individual different from othersEx: Galapagos finches vary in their beaksAdaptation: Variation that increases the chance of survivalEx: Which finch would be better adapted to an island with large seeds for food?
9 Butterflies won'tlay eggs on plantswith fake egg spots
12 Natural Selection in Action: The Peppered Moth Analysis Before the industrial revolution, the trees in the forest around Manchester, England were a light grey/green due to the color of lichens (fungus) on their trunks.
13 Natural Selection in Action: The Peppered Moth Analysis Peppered moths, or Biston betularia, which lived in the area were found in two varieties: 1) Light with dark spots (most common) and 2) Dark with light spots (less common).
14 Natural Selection in Action: The Peppered Moth Analysis Because there were not enough resources to support the entire population, the two varieties of this species had to compete for survival. Their coloring, when against a similar background, served as camouflage against predators such as birds and lizards, thus increasing chances of survival.
15 Natural Selection in Action: The Peppered Moth Analysis As the Industrial Revolution progressed, the trees became covered with sulfur dioxide, which killed the light colored lichen and thus turning the tree trunks dark.
19 Kobe Kuiz What is a theory? What did acquired inheritance state and how was it thought to work?What does natural selection state and how is it thought to work?How does a variation and adaptation differ?