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 (1/27/32 - 10/2/36) circumnavigation

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

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

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)

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

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?

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?

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

Relationship between species (beaks) & food

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

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

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

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 

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

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.

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.

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

Venomous Coral snake non–venomous Scarlet King snake

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