6The Darwin Dude 5 year voyage on Beagle (1831-36) Naturalist: surveyed coast of S.A.Wrote “Origin of Species”
7The Darwin Dude Collected: Rocks Fossils Plants Animals Charles Lyell’s Principles of Geology proposed Earth was millions of years old!
8Lyell: Explained marine life at high elevation in the Andes Giant fossil versions of smaller living mammalsEarthquakes could lift rocks great distances very quickly.
9Galapagos Island Facts Part of Ecuador13 main volcanic islandsFormed between MYA
10Darwin & Galapagos Organisms adapted to their environment “Darwin’s Finches”Gould (ornithologist) finches were separate species not found any where else.Mechanism for evolution = Natural Selection
11Artificial Selection: Darwin believed new species appear gradually through small changes in ancestral species.Breeders – can promote specific traits by selecting and breeding organisms that have the most exaggerated expressions of those traits.Known as Artificial Selection!
12Inference:If humans could change species by artificial selection, the same process could work in nature!Given enough time this process could produce new species!
20Thomas Malthus:Human population, if unchecked, would eventually outgrow its food supply, leading to a competitive struggle for existence.Darwin believed Malthus’s ideas could be applied to the natural world.Some competitors are better equipped for survival than others!
21Natural Selection Organisms with favorable traits survive & reproduce Variation is key
22Natural Selection (cont.) Struggle for existenceSpecies become better fit for their environmentIf not they could DIE!
23Natural Selection (cont.) 4 Main Principles (pg 421):VariationHeritabilityOverproductionReproductive Advantage
241. Variation: Individuals in a population differ from one another. Example:
252. Heritability:Variations are inherited from parents.Example:X
263. Overproduction:Populations produce more offspring than can survive.Example:48 white tiger litters produces 148 cubs105 of them died without reproducing 71%
274. Reproductive Advantage: Some variations allow the organism that possesses them to have more offspring than the organism that does not possess them.Example:White tigers have powerful jaws & teeth, very strong sense of smell, sharp eyesight, and excellent swimmers!
36V = Variation: All life forms vary genetically within a population. It is this genetic variation upon which selection works.I = Inheritance: Genetic traits are inherited from parents and are passed on to offspring.S = Selection: Organisms with traits that are favorable to their survival get to live and pass on their genes to the next generation.T = Time: Evolution takes time. Evolution can happen in a few generations, but major change, such as speciation, often takes long periods of time.
37Evidence of Evolution Fossil Record Fossils: preserved evidence Found in Sedimentary rock
38Evidence of Evolution Provides record of species that lived long ago. Some similar to current ones!Some species unchanged!
56Comparative Biochemistry: The more closely related the species are, the greater number of amino acid sequences they will share.Ex. Chimpanzees and Humans share 96% similar sequences!
57Humans & Chimpanzees:Human genome is 96% similar to great ape species.Pan troglodytes (species of chimp) used in studyThe number of genetic differences between humans and chimps is ten times smaller than that between mice and rats.
64Liger http://www.youtube.com/watch?v=WdTln4QwexQ&feature=related In addition to accidental Ligers there have been accidental Ti-Ligers (Female ligers who have bred with male tigers) and Li-Ligers (Female ligers who have bred with male lions). This has happened on several occasions due to wide spread myth. It was believed that the offspring of a Lion and a Tigress was infertile, therefore these beasts were often housed with other large cats. However, female ligers are not infertile and can (and will) produce offspring. These creatures resemble their fathers more than their mothers, this is believed to be due to the fact that they are then 75% of that type of cat, whether he be a lion or a tiger
65Species Loop Hole Not a perfect definition Used for classification Some different species can produce fertile offspring
70Cause of Speciation 3. Reproductive Isolation Examples: mating at different timesbirds mating with others who sing a particular song.
71Patterns of Evolution: Adaptive radiation (divergent evolution)CoevolutionConvergent evolution
721. Adaptive Radiation: Relatively short period of time 1 species gives rise to manyUsually occurs after mass extinctions
732. Coevolution:Evolution of 1 species affects the evolution of another species.
743. Convergent Evolution: Unrelated species evolve similar traitsUnder same environmentalpressuresMara and Rabbits: Maras have stocky bodies, three sharp-clawed digits on the hind feet, and four digits of the forefeet. Maras have been described as resembling long-legged rabbits. Patagonian maras can run at speeds up to 29 km (18 mi) per hour. Maras can weigh over 11 kg (24 lb) in adulthood.Most maras have a brown head and body, a dark almost black rump with a white fringe around the base, and a white belly.Maras may amble, hop in a rabbit-like fashion, gallop, or bounce on all fours. They have been known to leap up to 6 ft (1.8 m).