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Evolution Part I. Evolution. Changes in a population over time. Earths Position in the Universe. 400 years ago the general public thought that the earth was the center of the universe Sun revolves around the earth The earth does not move. Galileo and Corpernicus. - PowerPoint PPT Presentation
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Evolution Part I
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Evolution
• Changes in a population over time
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Earths Position in the Universe
• 400 years ago the general public thought that the earth was the center of the universe– Sun revolves around
the earth
– The earth does not move
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Galileo and Corpernicus
• Demonstrated scientific evidence that the sun is at the center of our solar system and the earth moves around the sun
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Galileo and the Church
• Religious leaders felt the heliocentric theory (sun at the center) was a direct contradiction to the literal interpretation of the Bible
• Galileo found guilty of heresy
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Copernican System (Heliocentral Theory)
• Did not destroy peoples belief in God
• Public now accepts the overwhelming evidence for the heliocentric theory
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Theory of Evolution
• Science has overwhelming evidence that all life is constantly evolving
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Charles Darwin 1809-1882
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HMS Beagle 1831-1836
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Ostrich in Africa Rhea in South America
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Adaptive Radiation
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Land Iquana
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Marine Iquana
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Different Tortoises on Each Island
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Origin of Species 1859
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Natural Selection
• One mechanism of evolution
• Main concepts of natural selection– Overproduction of offspring– Inherited variation in offspring– Competition – Best adapted in a given environment survive
and reproduce to increase their kind• They are naturally selected
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Overproduction of Offspring
• Elephants (very slow reproductive rate)– If all the offspring of one elephant pair survive and all
their offspring survive then:• 750 years = 19,000,000 elephants• 1200 years = Enough elephants to cover the earth!
• Beetles– A handful that weighs 10 mg each– 82 weeks
• 61,000,000,000,000,000,000,000 ton– The weight of the earth!
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Variation of Offspring
• Offspring of the same parents are different from each other
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Competition
• Since more individuals are born than can survive for an extended period of time, they compete for resources– Food– Living space– Mates
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Best adapted to a given environment are selected to survive
• Brown bears– Adapted to survive in
Oklahoma
• Polar bears– Adapted to survive in
Alaska
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Artificial Selection
Collie crossed with Scandinavia Spitz
Sheltie
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Evolution is Change• Changing alleles in a population can
produce new species
• Dogs have evolved from wolves
• Man has artificially selected traits to produce the various dog breeds
• Nature uses natural selection and other mechanisms for evolution
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Natural Selection of
Flies
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Scientific Disciplines That Give Evidence for Evolution
• Paleontology
• Comparative anatomy
• Biogeography
• Molecular biology
• Others
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Paleontology
• Study of fossils – Allows us to see
anatomical similarities between living species and organisms that lived in the past
– Allows us to see how life has changed over time
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Life Has Changed
• Millions of species have been found that are different from life today
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Horse Evolution
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50 Million Years of Change
50 MYA 30 MYA 15 MYA Modern
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Comparative Anatomy
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Homologous Structures• Same structures used for different purposes
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Homologous Structures
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HomoplasyAnalogous Structures
Similar structures due to convergent evolution,
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Biogeography
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Why No Polar Bears in Antarctica or No Penguins in Arctic?
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Why marsupials in Australia?
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Molecular Biology
• The study of the molecules of life including DNA and proteins
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DNA Similarity
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Homeobox or HOX
• First discovered in fruit flies in 1983
• Later found in mice, man and other organisms
• Controls embryonic development of different body regions
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Evolution of New Body Plan
• Hox gene Ubx of crustacean mutated in lab
• Caused suppression of leg development
• Mechanism for evolution of insect body plan 400 MYA
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Comparing DNA
• Human DNA compared to:– Chimpanzee 99% same
– Gorilla 97.7% same
– Orangutan 96.3% same
– Another human 99.9% same
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Comparing Protein Sequences
• Many proteins in all of man are identical
• Organ transplants require similar proteins in the donor and the recipient– A sibling or parent is often the best source for
an organ transplant
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Which would be the closest protein match for an organ transplant?
Assuming all are alive and healthy.
• A persons father
• A persons great grandfather
• A persons 10th great grandfather
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Molecular Clock
• The further you go back in time, the more proteins (and DNA) are different.
• Differences in protein sequences and DNA can be used to estimate time when two species shared a common ancestor
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Related Organisms
• Close similarity of protein sequences indicates close relationship
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Cytochrome C
• Protein used to release energy from food
• 104 amino acids• 20 of the amino acids
occupy the same position in all eukaryotes
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Comparison of Human Cytochrome C
• 100 amino acids different in tuna fish
• 12 amino acids different in a horse
• 8 amino acids different in a kangaroo
• 1 amino acid different in a monkey
• Identical to chimpanzee
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Pattern of Evolution Originally Based on Fossil Record
• DNA comparisons confirm the same pattern
• Protein sequences confirm the same pattern
• 150 years of research by thousands of scientists demonstrate beyond doubt that life evolves.