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Charles%20Darwin%20

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Darwin s achievements. Transformed biological science . Both style and content. Still the cornerstone of biology . Now the cutting edge of psychology – PowerPoint PPT presentation

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Title: Charles%20Darwin%20


1
Charles Darwin Natural Selection
2
Lifeline
  • Born 1809
  • Study (Edinburgh and Cambridge) 1825-1831
  • Voyage of the Beagle 1831-36
  • Retired to Down 1842
  • The Origin of Species 1859
  • Died 1882

Darwins home at Down, near London
3
Darwins achievements
  • Transformed biological science
  • Both style and content
  • Still the cornerstone of biology
  • Now the cutting edge of psychology
  • Transformed attitudes of humanity to our place in
    the universe

4
Not just an evolutionist
  • Not even a biologist to start with
  • Collected beetles for fun
  • Studied geology more seriously
  • Considered himself a geologist throughout the
    Beagle voyage and for some time after
  • Famous for working out how coral atolls are formed

5
Natural selection
  • Developed theory in complete isolation
  • In face of violent (religious) opposition
  • With no knowledge of genetics
  • With no knowledge of DNA
  • With no knowledge of plate tectonics
  • With no observations of natural selection
    actually occurring

6
Joining the Beagle Voyage
  • Not paid for 5 years on Beagle.
  • Actually, he had to pay!
  • Was lucky to get on
  • replaced someone who was shot in a duel
  • his father opposed him going
  • Mainly asked because of his class, to keep
    Captain Fitzroy company
  • It was the making of him

7
CHARLES DARWIN
  • Video Who Was Charles Darwin?

8
Galapogos, 1835
  • Portrayed as a Eureka experience.
  • Actually, was hugely homesick
  • Did not recognise significance until back in
    England, 1837.
  • Worked out theory much later.
  • First inkling of natural selection in 1838.
  • Turtles finches were key evidence
  • On boat home, ate turtles, dumped shells
  • Thought finches different species didnt even
    label them properly

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11
The Big Idea Natural Selection
Darwins sand walk at Down a daily thoughtful
stroll
  • He knew about fossils
  • Collected many for extinct animals
  • Knew about Lyells theory of evolution of
    geology
  • Read Malthus (an economist) on population and
    competition for resources.
  • Video Clip
  • His ideas developed steadily over 20 years

12
Alfred Russel Wallace
  • Thought of natural selection independently
  • Wrote to Darwin
  • Darwin had been working on book
  • Published a letter jointly
  • It was Darwin who put in the hard yards
    collecting and documenting evidence to support
    theory

13
Natural Selection
  • Process of change in populations over many
    generations
  • Individuals with certain traits survive local
    environmental conditions
  • Pass on favourable alleles to offspring
  • Environment exerts selective pressure
  • This has led to biodiversity

14
Assumptions of Natural Selection
  • Variation
  • -All members of a species display a variety of
    characteristics in their appearance and behavior.
  • -Many are inherited.

15
Assumptions of Natural Selection
  • 2. Competition
  • The number of offspring produced by individuals
    in a species exceeds the number of offspring that
    will survive to adulthood

16
Assumptions of Natural Selection
  • 3. Fitness
  • Some offspring, because of their differences,
    are better able to adapt to the conditions of the
    environment than others.

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18
Assumptions of Natural Selection
  • 4. Adaptation
  • The better-adapted organisms pass on their
    characteristics to their offspring and, as a
    result, the population changes.

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22
Descent with Modification
  • Darwin never used the word evolution in his
    book On the Origin of Species
  • Used the term descent with modification instead

23
Artificial Selection
  • Selective pressure exerted by humans on
    populations
  • Improve or modify particular desirable traits
  • Eg. Selective breeding in farm animals

24
Artificial Selection
  • In food crops
  • Wheat, corn, rice and veggies have all been
    selectively bred
  • Wild mustard plant has been modified to produce
    broccoli, Brussels sprouts, cabbage and
    cauliflower
  • Breed for nutritional value, as well as harvest
    yield and pest resistance

25
Designer Dogs
  • How many breeds of dogs are there now?
  • Examples
  • What do you get when you cross a Yorkie and a
    Poodle?

Yorkie-poo
26
Designer Dogs
  • What about a Pug and a Beagle?

Puggle
  • Or a Bichon Frize and a Poodle?

Bich-Poo
27
Consequences of Artificial Selection
  • In dogs respiratory problems (bulldogs) and hip
    dysplasia (labs)
  • In crops reduces genetic variation
    (monoculture)
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