Scientists Who Influenced Darwin James Hutton (1726-1797) Jean-Baptiste de Lamarck (1744-1829) Thomas Malthus (1766-1834) Charles Lyell (1797-1875)

James Hutton Hutton estimated that the Earth was millions of years old. At that time, Earth’s age was thought to be thousands of years old based on religious beliefs Earth is now estimated to be 4.54 billion years old

James Hutton Proposed the Plutonic theory – “volcanic activity was the source of rocks on the surface of the Earth” Evidence of repeated cycles of uplift & erosion in the geology of the land Introduced the idea of “repair” into geological history Previous idea was decay from initial creation

James Hutton Concluded incorrectly that the repeated cycles of decay & repair erased history from the geological record

Charles Lyell Student of James Hutton He was a geologist – one who studies the origin, history, and structure of the earth. He proposed the theory of Uniformitarianism – “all geologic phenomena may be explained as the result of existing forces having operated uniformly from the origin of the Earth to present time” Introduced “Stratigraphic Ages” – uses strata of different rocks to separate the ages of previous geological history Noted changes in fossils in strata to fix relative ages

Grand Canyon Formed by the Colorado River – water erosion initially, then soil and wind erosion Took millions of years, exposing nearly 2 billion years of the Earth’s history in rock strata

Hawaiian Islands Volcanic in origin Each made up of at least one primary volcano, although many islands are composites of more than one.

Shield Volcanoes Shield-volcano eruptions such as this one at Kilauea, Hawaii are not explosive, and they are hundreds of feet high rather than tens of thousands of feet high.

Shield Volcanoes Gently sloping mountains produced from a large number of generally very fluid lava flows A volcano emerging from beneath the ocean results in the formation of a new island Hawaiian Islands are built on the moving sea floor of the North Pacific A volcanic eruption can also destroy an area of land & all its inhabitants

Jean-Baptiste de Lamarck Believed there were multiple origins with gradual change over time No extinctions We did not all evolve from a common ancestor

Lamarck’s 3 Theories Desire to Change – Organisms change b/c they have an inborn urge to better themselves & become more fit for their environment Use & Disuse – Change occurs b/c organisms could alter their shape by using their bodies in new ways. If an animal did not use a particular part of its body, that body part would decrease in size & might finally disappear Passing on Acquired Traits – Acquired characteristics are inherited

Lamarck’s 3 Theories How was he incorrect?

Giraffe Evolution Look at these giraffes. How would Lamarck have explained their long necks? How would Darwin have explained their long necks?

Were you right?

Alfred Wallace Middle-class family Limited education, worked many jobs: construction, surveying, assistant to a watchmaker, teacher... Loved natural history and the outdoors Traveled to Brazil, explored the Amazon, sold collections of biological specimens, especially insects

Wallace’s Formative Years 1848: Wallace sailed for South America, gathered large collections of specimens 1852: Sailed back to England, ship caught fire and sank after 3 weeks! Passengers rescued but collections lost! 1854: Wallace collected in the Malay Archipelago & recognized the Archipelago as biologically divided by a narrow strait, separating Asian fauna from Australian fauna, still recognized as Wallace's Line. 1859: Gathered more than 14,000 species in Brazil

Wallace Forms His Ideas on Natural Selection Applied geological idea of uniformitarianism to biology Charts of a species might look more like a tree than a straight line No species came into existence unless coexisted with another similar species that was its predecessor 1855: Wrote paper arguing for evolution of species.

Wallace and Darwin June 1858: Wallace drafted his thoughts, sent them in letter to Darwin, Darwin was very upset because Wallace got published first (Remember, in Science you win if you get your research published FIRST!) July 1858: Joint credit was given to Darwin & Wallace The announcement attracted no particular scientific or public attention (nobody really cared about their theories)! 1859: Darwin worked intensely for the next year on his manuscript, On the Origin of Species by Means of Natural Selection (1859) HIS BOOK WAS A BEST-SELLER, SOLD OUT ON THE FIRST DAY OF PUBLICATION!!!!

Thomas Malthus What does this image indicate?

Thomas Malthus Population grows exponentially while resources grow arithmetically When the population exceeds the resources, populations will begin to die off until reasonable numbers are reached Name three factors that reduce population sizes.

3 Factors That Limit Population Famine – an extreme & general scarcity of food, as in a country or large geographical area Plague – an epidemic disease that cause high mortality War – military conflict

Malthusian Graph Explain what is meant by the graph above.

Malthusian Graph Carrying capacity is the maximum number of organisms of a particular species that can be supported indefinitely in a given environment Population increases at a much faster rate then the available resources such as food, shelter, clothing, etc. When the population exceeds the available resources necessary for life, the population will begin to die off.

Now…go answer the questions