Timeline of Darwin’s life Born 1809 Study (Edinburgh and Cambridge) 1825-1831 Voyage of the Beagle...
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Transcript of Timeline of Darwin’s life Born 1809 Study (Edinburgh and Cambridge) 1825-1831 Voyage of the Beagle...
Timeline of Darwin’s lifeBorn 1809Study (Edinburgh and Cambridge) 1825-1831
Voyage of the Beagle 1831-1836Retired to Down 1842The Origin of Species 1859Died 1882
Not just an Evolutionist Not even a biologist to start withCollected beetles for funStudied geology more seriouslyConsidered himself a geologist
throughout the Beagle voyage and for some time after
Famous for working out how coral atolls are formed
An atoll is a ring-shaped coral reef, island, or series of islets. An atoll surrounds a body of water called a lagoon. Sometimes, atolls and lagoons protect a central island. Channels between islets connect a lagoon to the open ocean or sea.
His books (not just on evolution)Beagle voyageCoral reefsVolcanic islandsGeology of South
AmericaBarnaclesSpeciesMan
• Emotions• Climbing plants• Domestication• Cross and self
fertilization• Orchids• Worms• Autobiography
Contributor’s to Darwin’s thinking included:
Charles Lyell- Uniformitarianism is the assumption that the natural processes operating in the past are the same as those that can be (1797-1875) observed operating in the present.
Georges Cuvier –species extinction (1769-1832)
More people that contrubutored to Darwin’s ideas.
Thomas Malthus- struggle for existence 1766-1834
Jean Baptisite de Lamarck- evolution by acquired characteristics 1744-1829
Alfred Russell WallaceThought of natural selection at the same time as
Darwin (1959)Wrote to Darwin, collaborated with Darwin on
solidifying the theory of evolution through natural selection.
Darwin had been working on bookPublished a “letter” jointlyWallace didn’t put in the years of data that
Darwin did.Darwin published The Origin of Species without
Wallace
Darwin was MiscreditedDied famous for evolution (which
was not his idea)Natural selection was his big idea--
not widely accepted, even among his supporters
Darwin remained convincedOnly 40-50 years later did scientists
appreciate his foresight.
Charles Darwin’s IdeasNaturalist on the HMS Beagle, Five
year journeyVisits the Galapagos IslandsHe studied many organisms that
were unique to the islands, but similar to elsewhere.
After 22 years he proposed the process of natural selection.
The Voyage of the Beagle
Darwin’s Finches
Galapagos Islands500-600 miles west off the coast of EcuadorLocated directly on the equatorCold ocean coming from the south and warm
ocean current coming from the north meet at the islands
Galapagos Islands• Islands are of
volcanic origin (much like the Hawaiian islands)
The oldest islands are thought to be 5-10 million years old. (much younger than South America)
Started as a “blank slate.”
Not paid for 5 years on Beagle. Actually, he had to pay! Was the “Naturalist”Was lucky to get on
Replaced someone who was shot in a duelhis father opposed him going
Mainly asked because of his class, to keep Captain Fitzroy company
It was the making of him
Joining the Beagle Voyage
Portrayed as a “Eureka” experience. Did not recognize significance until back in England, 1837.Worked out theory much later.First inkling of natural selection in 1838.
Tortoises & finches were key evidence
Galapagos, 1835
How did living things get to the islands?Remember they have to survive a 500 mile journey.
Rafting on debris or chunks of land.
Birds may fly or be blown out in a storm.
How would you survive in this environment?
Galapagos Islands
Marine Iguana• Have been thought to evolve from an
ancestor similar to what we know as a green iguana.
Marine Iguana Live by
swimming in the ocean and scrapping algae off rocks.
Only known iguana that swims.
Marine Iguana CharacteristicsFlat Nose – Why?To scrape algae off
rocks.
Marine Iguana CharacteristicsLong, flat tailAllows it to swim in
the oceanBig clawsAllows it to hold
onto rocks while feeding
Marine Iguana CharacteristicsWhite stuff on back –
What is it?Salt – Salt glands in
nose– eats salty foods and the glands allow it to sneeze the salt out
Black Color – Why?Allows it to warm up
after being in the cold ocean
Land Iguana• Have been thought to evolve from an
ancestor similar to what we know as a green iguana.
Land Iguana
Lives on the landIs an Herbivore, eating mostly the fruit and
pads of cactus
Land Iguana CharacteristicsBigger jaw/mouth
than the marine iguana – WHY?
Allows it to eat cactus
Lighter coloring –WHY?
Doesn’t heat up as fast.
Land Iguana CharacteristicsNeck flap (gular sack)
WHY?Acts as a cooling system,
allows heat to escape body
Short, stubby legs – Why?
Allows it to support it’s big weight
Bigger Body – WHY?Resists heating up in the
desert sun
SOMETHING TO THINK ABOUTWhy did the land iguana and marine iguana evolve so differently from one another?
Galapagos Tortoise
Galapagos TortoiseHave been thought to evolve from an
ancestor similar to our desert tortoise.
Galapagos Tortoise CharacteristicsLive around 150
yearsThere were around
250,000 around Darwin’s time.
Numbers have declined to 15,000 or less.
Key source of meat for pirates and explorers.
ContinuedHigh shell at neck – Why?Allows it to stretch to reach
food.Bigger body size – Why?Takes longer for an organism to
warm up in the hot desert sun.
Plants Evolve Too!
Swallow-tail GullFlies and feeds at night
Swallow-tail Gull CharacteristicsDark, Black coloring –
WHY?Allows it to fly at night
without being spotted by Frigate Bird
Red Ring around the eye – WHY?
Red eye ring is thought to attract more light to allow bird to see at night.
White spot on beak – WHY?
When feeding at night chicks can peck on the white spot to tell the mother where they are.
MockingbirdMockingbirds will
peck at the iguanas, tortoises, and other birds and drink their blood during hard times when water is scarce.
This is an example of a behavioral adaptation.
How have humans impacted the islands?Introduced Exotic Species
Pigs, dogs, catsInvasive species of plants
TourismMany people travel to the islandsWhile the islands are mostly national parks and quite
regulated, they have to deal with the conservation problems that humans yachts and trash bring to the islands.
Increase in PopulationPeople are moving to the islands looking for workThe increase in tourism brings the need for more workersThis puts more pressure on the natural resources of the
islands
Natural SelectionA mechanism for change in populations.
Natural Selection1. In nature,
organisms produce more offspring than can survive.
2. In any population, individuals have variations.
3. Individuals with certain useful variations survive in their environment, passing those variations to the next generation. “Survival of the Fittest”
4. Over time, offspring with certain variations make up most of the population and may look entirely different from their ancestors.
Peppered MothsOnline Example