3 2) Charles Darwin1831At only 22 years old, this British nature lover went for a 5-year cruise onboard her majesty’s Beagle ship.He sailed around the world to look at stuff. The most famous stop being the Galapagos islands off the coast of South America.
8 3) Darwin’s NotesObservation 1:Overproduction – Organisms make more offspring than can survive.Observation 2: Resources are Limited.Conclusion 1: Competition for survival and reproduction among species.Observation 3: Individuals Differ from one another within a species’ population.Conclusion 2: Fitness – the most well-adapted individuals from one generation will usually leave the most offspring.
9 4) Twenty Years LaterDarwin finally publishes his book On the Origin of Species, sharing his theory of Evolution by Natural Selection (1859).
10 5) Darwinian Terms Natural Selection- Nature selects who stays!! This is what drives evolution.Evolution- change in population genotypes from one generation to the next.a.k.a. change over time.
11 Variation- Differences between individuals of the same species. Adaptation- A trait that helps an organism to survive & reproduce (born with it).Adaptations are favorable variations.Variation- Differences between individuals of the same species.Examples: color, shape, size, behavior, chemistry.Variations come from:Mutations.Meiosis Cross Over (challenge topic)
12 Populations will have a pool of genes. A gene pool is all the genes that occur in a population.
14 Introduction:Recall that a scientific theory is testable; and explains many observations.A claim must have evidence.In other words, show sound reason, or be logical.So…Show me the proof that biological evolution accounts for the origin of species.
15 1) FossilsFossils are the remains of past life dug up from the earth’s crust.Fossil formation is rare.Most fossils form in sedimentary rock.Examples of Fossils:Bones, teeth, molds, casts, impressions.Because the Earth’s crust is layered over time, younger fossils are found closer to the top.
17 1a) Fossil RecordIf you piece together all the millions of fossils that scientists have dug up and sequence them by time (age), you have the Fossil Record.How do you know a fossils age?Relative datingTop vs. Bottom layers.Radioactive datingUnstable element decay of nearby rocks.
19 2) EmbryologyLooking at the early development of one organism and comparing it to another allows scientists to make inferences about their evolutionary relationship.Embryo: Not yet born, developing multicellular organism.Inference: using clues to make a conclusion.
31 6) SummaryEvolution by means of natural selection explains the history of life on earth. This claim is supported by an abundance of evidence.Key Concepts are:Species share common ancestors.Descent with modification: (perpetual change)Nature chooses which species stay (extant) and which go (extinct).
32 7) High School Challenge Describe the role that geographic isolation can play in speciation.Speciation = new species formation.Research:Allopatric speciationVicariant vs. founder effect.Sympatric speciation
33 Darwin’s Work1. Variation: There is Variation in Every Population. 2. Competition: Organisms Compete for limited resources. 3. Offspring: Organisms produce more Offspring than can survive. 4. Genetics: Organisms pass Genetic traits on to their offspring. 5. Natural Selection: Those organisms with the Most Beneficial Traits are more likely to Survive and Reproduce.
34 The History of Evolutionary Thought Plato (Greek philosopher B.C.E.)-Aristotle (Plato’s student BCE)-