2. Charles Darwin Son of wealthy businessman
Trained at Oxford U to become a minister
Avid naturalist
Had to get father’s approval for
Voyage of the Beagle (1/27/ /2/36)
circumnavigation

3. Charles Darwin After return, published The Voyage of the Beagle
Gave up plans to become a minister
Focused on his natural history studies
Agonized over revolutionary ideas of natural selection
Not enough evidence ?
Concerned about scientific reputation
Wallace’s 1858 letter with similar ideas provided additional evidence and impetus to publish first

4. Alfred Russel Wallace Came from poor family Left school at age 13
Keen student of natural history, esp. variation within species
Traveled extensively in S. America and East Indies

5. Alfred Russel Wallace
Between April, 1854 and February, 1862 Wallace traveled in the little explored Malay Archipelago, between Asia and Australia.
In 1858, during a bout of malaria in the Spice Islands, he conceived the theory of evolution by natural selection.
Sent letter to Darwin explaining his ideas
Darwin presented Wallace’s and own ideas to Linnean Society of London (7/1/58)

6. Later…
Darwin published On the Origin of Species by Means of Natural Selection (1859); Wallace credited
Revolutionary ideas backed by evidence and solid reasoning
Died in 1882
Wallace continued to travel, explore and publish scientific papers on the Malay archipelago (modern day Malaysia & Indonesia)
Died in 1913

7. Darwin’s Finches
Finch?
Sparrow?
Woodpecker?
Warbler?
Darwin found many different birds on the Galapagos Islands.
Finch?
Sparrow?
He thought he found very different kinds…
Woodpecker?
Warbler?

8. But Darwin found… a lot of finches
Darwin was amazed to find out:
All 14 species of birds were finches…
Finch?
Sparrow?
Woodpecker?
Warbler?
But there is only one species of finch on the mainland!
Large ground finch
Small ground finch
Finch?
Sparrow?
Darwin asked:
If the Galapagos finches came from the mainland, why are they so different now?
Warbler finch
Tree finch
Woodpecker?
Warbler?

9. The finches cinched it! Darwin found:
Ahaaaa! A flock of South American finches were stranded on the Galapagos…
The finches cinched it!
Darwin found:
The differences between species of finches were associated with the different food they ate.
Finch?
Sparrow?
Woodpecker?
Warbler?
different beaks are inherited variations
serve as adaptations that help birds compete for food
these birds survive & reproduce
pass on the genes for those more fit beaks
over time nature selected for different species with different beaks
Large ground finch
Big seed eater
Small ground finch
Small seed eater
Insect eater
Warbler finch
Leaf & bud eater
Tree finch

10. Relationship between species (beaks) & food

11. Darwin’s finches Darwin’s conclusions Variations in beaks
differences in beaks in the original flock
adaptations to foods available on islands
Natural selection for most fit
over many generations, the finches were selected for specific beaks & behaviors
Offspring inherit successful traits
accumulation of winning traits: both beaks & behaviors
Separate into different species

12. From 1 species to 14 species…
Warbler finch
Woodpecker finch
Small insectivorous
tree finch
Large
insectivorous
Vegetarian
Cactus finch
Sharp-beaked finch
Small ground
finch
Medium
ground finch
Large ground
Insect eaters
Bud eater
Seed eaters
Cactus
eater
Warbler
Tree finches
Ground finches
natural selection for best survival & reproduction
variation

13. Earlier ideas on Evolution
LaMarck
evolution by acquired traits
creatures developed traits during their lifetime
give those traits to their offspring
example
in reaching higher leaves giraffes stretch their necks & give the acquired longer neck to offspring
not accepted as valid

15. Darwin’s view of Evolution
giraffes that already have long necks survive better
leave more offspring who inherit their long necks
Variation
Selection & survival
Reproduction & inheritance of more fit traits 

16. Artificial Selection
Artificial selection, nature provides the variations, humans select those they find useful. Darwin tested with artificial selection by raising pigeons.

18. Natural Selection
The process by which organisms with variations most suited to their local environment survive and leave more offspring.
Natural selection occurs in any situation in which more individuals are born than can survive, there is natural heritable variation, and there is variable fitness among individuals.
Struggle for existence
Variation and adaptation
Survival of the fittest.

19. Struggle for Existence
Inspired by Malthus, a scientist who believed that if all humans were to survive and population grew unchecked, there wouldn’t be enough resources for everyone, so war, famine, and disease controlled our population.
Darwin applied this to other species and realized that some species produce millions of offspring each year, and if they were all to survive, there wouldn’t be enough space for all species.
So if more individuals are produced than can survive, members of a population must compete to obtain food, space, and other necessities of life.

20. Variation and Adaptation
Some variations are more suitable than others.
Any characteristics that increases an organism’s ability to survive and reproduce in its environment is called an adaptation.
Ex. Ability to run fast in deer
Camouflage
Mimicry
Plants ability to photosynthesize

21. Venomous Coral snake non–venomous Scarlet King snake

22. Survival of the Fittest
Differences in adaptations affect an individual’s fitness, which impacts how well an organism survives and reproduces in its environment.
Individuals with adaptations that are well suited for their environment can survive and reproduce and are said to have high fitness.
Assignment
Page 479
#1-12- Answer in complete sentences