History of Evolution

• 1831, Darwin, naturalist on H.M.S. Beagle• Galapagos, Coast of S. America• James Hutton(1785)– earth is millions, not

thousands of years old• Thomas Malthus (1798) – predicted that the

population of earth would exceed it’s resources• Jean-Baptiste Lamarck(1809) – proposed that

inheritance was acquired (1st mechanism for organisms changing over time)

Cont.

• Darwin (1831) – naturalist who proposed the theory of evolution (1859) On the Origin of Species

• Charles Lyell (1833)- proposed that the process occurring now have shaped the earth for long periods of time; published Principles of Geology

• Alfred Wallace (1858)– contemporary of Darwin, speculated on evolution through natural selection

Theory of Evolution

• Fitness – individuals ability to survive and reproduce in it’s environment

• Adaptation – inherited traits/characteristics that increase the chance of survival

• Artificial selection – humans manipulate traits

• Natural selection – inherited over time by the process of nature (can not be seen directly)

• Over time organisms produce different structures, establish different niches, or occupy different habitats – descent with modification

• Fossil record supported Darwin’s theory

• Fossil record shows how species have changed overtime or died

Formation of Earth

• 4.6 billion years old (universe 15 billion)• Elements arranged themselves by

densities creating the planet (radioactive decay creates heat, core heaviest metals) least dense formed early atmosphere (H and N)

• Atmosphere was toxic to life as we knew it (it was what we didn’t know could exist in this environment, cyanobacteria)

Cont.

• 3.8 billion, earth cooled enough to allow water to remain liquid, creating rain

• Under these conditions, organic compounds were formed (building blocks for life)

• DNA is transcribed into RNA then translated into proteins

Oxygen-evolution

• 2.2 billion increase in oxygen allowed organisms to evolve (move from water to land)

• 2 billion eukaryotic cells (nucleus) appeared, endosymbiotic theory proposes that eukaryotes evolved from prokaryotic communities

Geologic Time Scale

Cont.

• 90% of earths history occurred during Precambrian (life only existed in the water)

• Paleozoic Era – abundance of marine life• Cambrian – hard parts appear, most

animal phyla evolve• Devonian – vertebrates appear• Mass extinction occurs• Mesozoic Era – rise of dinosaurs and

flowering plants

Cont.

• Jurassic – dino’s ruled the earth for 150 million yrs.

• Cretaceous – leafy trees, shrubs, flying birds, large reptiles still dominant earth

• Mass extinction (meteor) wipes out half of all plant and animal groups (including all of the dino’s)

• Cenozoic Era – animals evolve adaptation for land, water and air

Pattern of Evolution

• 99% of all species that have lived are now extinct.

• Macroevolution – large scale evolutionary patterns and processes that occur over long periods of time

• 6 specific areas of macroevolution – extinction, adaptive radiation, convergent evolution, coevolution, punctuated equilibrium, and changes in developmental genes