UNIT 3 DARWIN AND MENDEL I Darwins Contributions

UNIT 3: DARWIN AND MENDEL

I. Darwin’s Contributions

I. Darwin’s Contributions A. Life - Born Feb 12, 1809

I. Darwin’s Contributions A. Life - Born Feb 12, 1809 - Graduated Cambridge, intending to join the clergy

I. Darwin’s Contributions A. Life - Born Feb 12, 1809 - Graduated Cambridge, intending to join the clergy - 1831 -36, Naturalist on H. M. S. Beagle

I. Darwin’s Contributions A. Life - Born Feb 12, 1809 - Graduated Cambridge, intending to join the clergy - 1831 -36, Naturalist on H. M. S. Beagle - 1859: Origin of Species

I. Darwin’s Contributions A. Life - Born Feb 12, 1809 - Graduated Cambridge, intending to join the clergy - 1831 -36, Naturalist on H. M. S. Beagle - 1859: Origin of Species - Died April 19, 1882, interred in Westminster Abbey

B. The Origin of Species

B. The Origin of Species 1. “One Long Argument” - observations leading to the conclusions that: - life changes through time

B. The Origin of Species 1. “One Long Argument” - observations leading to the conclusions that: - life changes through time - species descend from shared ancestors A B C

B. The Origin of Species 1. “One Long Argument” – evidence of ancestry 2. Proposed Hypothesis for HOW change occurs: - Natural Selection

B. The Origin of Species 1. “One Long Argument” – evidence of ancestry 2. Proposed Hypothesis for HOW change occurs: - Natural Selection 3. Dilemmas – things that didn’t “fit”

C. Observations 1. Geology - The Earth is OLD - James Hutton (1726 -1797) Scottish Geologist

Hadrian’s Wall, but by the Roman Emperor Hadrian in 122 A. D. 2000 years old, but no sign of erosion. How much older must highly worn and eroded granite outcrops be?

And how long must it have taken for the layers of sediment comprising the White cliffs of Dover to accumulate? If rates of erosion and mountain building have been uniform, governed by the processes we see operating in nature today, then: "(in geology) we find no vestige of a beginning, —no prospect of an end. " …. (The Earth is immeasureably old. )

C. Observations 1. Geology - The Earth is OLD - Charles Lyell (1797 -1875) British Geologist Principles of Geology Promoted the concept of UNIFORMITARIANISM (slow, steady change, accumulating over long periods of time, can result in major effects…)

C. Observations 2. Paleontology a. Major groups appear at different times - additive recent Mammals Birds Reptiles Amphibians Jawed fishes past Jawless fishes

C. Observations 2. Paleontology b. Within a lineage, there are patterns of gradual change

C. Observations 2. Paleontology b. Within a lineage, there are patterns of gradual change c. Within a lineage, there are patterns of radiation (many descendants from few ancestors).

C. Observations 3. Comparative Anatomy - Homologous Structures

C. Observations 3. Comparative Anatomy - Homologous Structures Same structure, but different uses in different environments (correlated pattern)

C. Observations 3. Comparative Anatomy - Analogous Structures

C. Observations 3. Comparative Anatomy - Analogous Structures Different structures, but same uses in the same environment. (again, a correlation between anatomy and environment)

C. Observations 3. Comparative Anatomy - Vestigial Structures – Whale hip bones

C. Observations 3. Comparative Anatomy- Vestigial Structures Human structures

Argentina C. Observations 4. Biogeography - Community Convergence In similar environments, there are organisms that fill similar ecological roles – and they are morphologically similar. Correlated patterns… Australia

C. Observations 4. Biogeography – Island Faunas

C. Observations 4. Biogeography – Island Fauna - Fauklands – species same as mainland - Galapagos – species different from mainland a. degree of isolation correlated with uniqueness of inhabitants…. .

Voyage of the Beagle – Darwin (1845) "The natural history of these islands is eminently curious, and well deserves attention. Most of the organic productions are aboriginal creations, found nowhere else; Flightless Cormorant

“…there is even a difference between the inhabitants of the different islands; yet all show a marked relationship with those of America, though separated from that continent by an open space of ocean, between 500 and 600 miles in width. ” Green Iguana – Central and South America

“…The archipelago is a little world within itself, or rather a satellite attached to America, whence it has derived a few stray colonists, and has received the general character of its indigenous productions. Considering the small size of the islands, we feel the more astonished at the number of their aboriginal beings, and at their confined range. ” Galapagos Land Iguana, pallid species, only on Santa Fe island.

“… Seeing every height crowned with its crater, and the boundaries of most of the lava streams still distinct, we are led to believe that within a period geologically recent the unbroken ocean was here spread out. ”

“…Hence, both in space and time, we seem to be brought somewhat near to that great fact -- that mystery of mysteries -the first appearance of new beings on this earth. ” The Voyage of the Beagle – Charles Darwin

C. Observations 4. Biogeography – Island Faunas a. Isolation correlates with uniqueness

C. Observations 4. Biogeography – Island Faunas a. Isolation correlates with uniqueness b. islands are dominated by dispersive forms