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EVOLUTION.

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Presentation on theme: "EVOLUTION."— Presentation transcript:

1 EVOLUTION

2 Early theories (pre-1700’s)
nature is seen as not changing and having originated through spontaneous generation Carolus Linnaeus was the first one to try to classify life (1735, placed us with primates)

3 1700’s an understanding of the age of the Earth develops through geology inheritance of acquired traits (use and disuse) ex. Baby giraffes are born with long necks because their parents stretched their necks to reach leaves (Jean-Baptiste Lamarck, 1801)

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5 Darwin and the Voyage of the Beagle
in December, 1831’s, Charles Darwin, a naturalist in his 20’s began a 5-year journey around the world on a ship called HMS Beagle Darwin’s role was to observe, record, and collect specimens of rocks, minerals, plants, and animals from a well- educated family, , in part to find evidence to support biblical creation (Darwin left England believing in the immutable nature of species) - when they got to Galapagos, a chain of volcanic islands off the coast of Ecuador, Darwin saw that although a lot of the species were similar to those of the S. America’s mainland, they had some unique traits

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8 Darwin: PBS

9 Darwin collected 1000’s of specimens and shipped them to England, mainly from South America and a chain of volcanic islands called Galapagos he collected them but did not realize what he was seeing until years later (ex. didn’t catalogue the finches very well, ate turtles that would later support his theories, etc.) Darwin spent the next 20 yrs analyzing his findings in light of artificial selection (ex. breeding of pigeons, breeding of dogs, etc.)

10 Darwin’s Finches Arrival Success Competition Diversity & Opportunity
Radiation How does evolution really work?

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12 Hawaiian honeycreeper

13 Natural Selection as the Cause of Evolution
- called “natural selection” because it happens on its own 1. Genetic Variation - there are many varieties of alleles - caused by random mutations - can be passed onto offsprings (inherited variation) 2. Overproduction of Offsprings - organisms make too many offsprings

14 3. Struggle for existence
- competition for limited resources 4. Differential survival and reproduction - only organisms that have certain characteristics will survive to reproduce - non-random, caused by the environment: amount of food, competition (ex. Darwin’s finches)

15 PBS Evolution: The Evolutionary Arms Race (12 min)

16 Sideways Sharks Up & Down Dolphins
Wiggles work Limbs for leverage Upright & under Stepping & Striding Arching & Aquatic

17 All of this takes a LOOOOOOONG time


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