Geologic Processes, Climate Change and Evolution  Location of continents and oceanic basins influence the earths climate, determining where plants and animals can live.  The movement of continents has allowed species to move, adapt to new environments and form new species through natural selection. Continental movement, earthquakes and volcanoes can isolate, join together or destroy populations.

pANGAEA In 1915, the German geologist and meteorologist Alfred Wegener ( ) first proposed the theory of continental drift, which states that parts of the Earth's crust slowly drift atop a liquid core. The fossil record supports and gives credence to the theories of continental drift and plate tectonics. Wegener hypothesized that there was an original, gigantic supercontinent 200 million years ago, which he named Pangaea, meaning "All-earth". Pangaea was a supercontinent consisting of all of Earth's land masses. It existed from the Permian through Jurassic. It began breaking up during the late Triassic period.

Changing climates- species can’t adapt fast enough Asteroids colliding wit h the earth

Changes in Ice Cover

How do speciation, extinction, and human activities affect biodiversity? Under certain circumstances, natural selection can lead to an entirely new species. This process is called speciation and is when 2 species arise from 1. A new species has formed when some members of the population can no longer breed with other members to produce fertile offspring. (refer to speciation webquest for details)

How Do New Species Evolve? Geographic isolation (allopatric) Migration, separation by a physical barrier, carried away by wind or water Reproductive isolation- geographic separation prevents reproduction, mutations in one population occur, and a new species forms.

Geographic Isolation Can Lead to Reproductive Isolation

Extinction is Forever Extinction Endemic species – species found in only one area Particularly vulnerable ( Golden toad in Costa Rica is extinct lived in a small area in the cloud rain forest)

Background extinction- normal rate of extinctions Mass extinction- a significant rise in extinction rates where 25-95% of species may be wiped out. 5 mass extinctions have occurred Mass extinctions give opportunity for the evolution of new species to fill unoccupied niches or to create new ones. Many believe we are headed toward the 6 th mass extinction.

Background extinction- normal rate of extinctions Mass extinction- a significant rise in extinction rates where 25-95% of species may be wiped out. 5 mass extinctions have occurred Mass extinctions give opportunity for the evolution of new species to fill unoccupied niches or to create new ones. Many believe we are headed toward the 6 th mass extinction.

What Roles Do Species Play in Ecosystems? Ecological niche, niche Pattern of living Generalist species Broad niche Specialist species Narrow niche

Specialized Feeding Niches of Various Bird Species in a Coastal Wetland

Niches Can Be Occupied by Native and Nonnative Species Native species Nonnative species; invasive, alien, or exotic species May spread rapidly Do not have natural predators Compete with native species Not all are villains

Keystone, Foundation Species Determine Structure, Function of Their Ecosystems Keystone species – important for the entire community/ecosystem Pollinators- bees and bats Top predators – alligator, wolf, lion Ex: krill, sea star, gopher tortoise, sea otter, beaver Foundation species Create or enhance their habitats, which benefit others Ex: elephants, beavers Some species can be both a keystone and foundation species

Most of what we know of Earth’s life history comes from fossils Mineralized or petrified replicas of skeletons, bones, teeth, shells, leaves and seeds Core samples from glacial ice The fossil record- an uneven and incomplete record Fossils found probably represent only 1% of all species that have ever lived! Paleontologists study fossils. Fig. 4-3, p. 81

A more common time limit defines fossils as being prehistoric thus; fossils preserve remains or activities of ancient organisms older than 10,000 years The majority of fossils are found in sedimentary rocks. Organisms become trapped within sediment layers due to the action of water, wind or gravity.

Fossilization often occurs as a result of rapid burial, usually by water-borne sediment, followed by chemical alteration. Rapid burial and specific chemical environments help to reduce decomposition from bacteria and fungi.

There are six ways that organisms can turn into fossils, including: unaltered preservation (like insects or plant parts trapped in amber, a hardened form of tree sap) permineralization=petrification (in which rock-like minerals seep in slowly and replace the original organic tissues with silica, calcite or pyrite, forming a rock-like fossil - can preserve hard and soft parts - most bone and wood fossils are permineralized) replacement (An organism's hard parts dissolve and are replaced by other minerals, like calcite, silica, pyrite, or iron) carbonization=coalification (in which only the carbon remains in the specimen - other elements, like hydrogen, oxygen, and nitrogen are removed) recrystallization (hard parts either revert to more stable minerals or small crystals turn into larger crystals- mostly in oceans) authigenic preservation (molds and casts of organisms that have been destroyed or dissolved).

“All we have yet discovered is but a trifle in comparison with what lies hid in the great treasury of nature.” Antoine Van Leeuwenhoek