8-3 NOTES: DARWIN VS. LAMARCK

BEFORE DARWIN People believed earth was only thousands of years old and organisms did not change. However, this did not explain the fossil record that showed very different organisms living in areas in the past.

EVOLUTION o Development of new types of organisms from preexisting organisms over time. o Two scientists had theories as to how organisms changed over time. o Darwin and Lamarck

Lamarck’s Ideas o Proposed the idea of acquired traits to explain the changes. o Changes in environment caused an organism behavior to change creating a new physical trait.

Lamarck’s ideas o Traits used most often would be enhanced and passed to offspring o Traits that were not used would diminish and disappear from offspring Using what we know about genetics, can we disprove the theory of inheritance of acquired traits? Using what we know about genetics, can we disprove the theory of inheritance of acquired traits?

Darwin’s Ideas o Argued that descent with modification occurs o Proposed that Natural selection is the mechanism for evolution. o Darwin’s idea that small changes accumulate over generations.

Darwin’s Ideas o The variation of trait that is beneficial for survival became more common. o Ex. Giraffes with slightly longer necks survived and reproduced

VOYAGE ON THE H.M.S BEAGLE o Darwin went on a five year voyage where he collected many artifacts

VOYAGE ON THE H.M.S BEAGLE o Went to Galapagos Islands and noticed variations of animals were well suited to animals environment o variation- differences in physical traits

Darwin’s Finches o 13 finch species that evidence suggests descended from one original species from Ecuador

Darwin’s Finches o Each island had different climates and food sources o Each finch species beak was best suited for eating the available food source

VOYAGE ON THE H.M.S BEAGLE o He said some how they had to adapt to their surrounding!

VOYAGE ON THE H.M.S BEAGLE o Darwin observed fossil and geologic evidence supporting an ancient Earth. o Suggested that modern organisms have relationship to fossil forms.

VOYAGE ON THE H.M.S BEAGLE Darwin said, like the Earth, organisms must some how gradually change over time

DARWIN VIDEO

CLASS WORK Darwin and Lamarck 4-squares Darwin vs. Lamarck