1

Supercontinent - Pangea . . .

(zoom in to view the names of the geologic eras)

Alfred Wegner

Supercontinent - Pangea . . .

PangeaGondwanalandLaurasia

2

Geologic Time

Milankovitch Cycles(~ 100,000 years)

Milutin Milankovitch(1879-1958)

Milankovitch Cycles(~ 100,000 years)

3

Factors affectingEarth’s Climate

1. Milankovich Cycles(~100,000 years)

2. Pacific Decadal Oscillation(~10 – 15 years)

3. El Nino/La Nina Cycles (annual cycles*)

• Pleistocene Epoch– Ice ages (WIKN) – Humans appear – 1.8 my to 10,000 yr

http://www.museum.state.il.us/exhibits/ice_ages/images/loopglac.gif

Time Scale: The Cenozoic Era“Recent Life”

Stages

Continental Glaciers . . . . .

What is a “nunatak”?

Nebraskan(oldest)

Kansan

Illinoian

Wisconsin(most recent)

4

Human Migration

NationalGenographic

Project

Human Migration

Source: www.utexas.edu/features/2007/ancestry/

Continental Glaciers . . . . .

Question: What type of vegetation covered the

landscape immediately south of the continental glaciers?

5

Glaciers, Biotic Exchange,and Vegetation Patterns

Vegetation Patternsduring Glacial Periods

North American Glaciers . . . . .

Note the names

and locations

of the refugium

6

Glacial Lake Missoula

Glacial Lake Missoula

The name Missoula is derived from a Flathead (Salish) termmeaning “cold, chilling waters”.

Continental Glaciers . . . . .

How did the continental glaciers affect the Willamette

Valley?

7

Glacial Lake Missoula

Glacial Lake Missoula

A Sudden Onslaught of Water

The Dalles, Oregon ~ 1,000 feet

8

Question.. . . . . . . . .

Question: As the glaciers formed, they locked up water,

how much lower were sea levels then?

Astoria Trench

Pacific Salmon Species

Genus Oncorhynchus – “hooknose”

Pink Salmon (O. gorbuscha)

Chum Salmon (O. keta)

Sockeye Salmon (O. nerka)

Coho Salmon (O. kisutch)

Chinook Salmon (O. tshawytscha)

Steelhead Trout (O. mykiss)

Sea-run Cutthroat Trout (O. clarkii)

9

Glacial Lake Missoula

Glacial Erratics

The lake was named after the early explorer, B.L. Bonneville. It was formed about 50,000 years ago and had receded to the current level of the Great Salt Lake by about 10,000 years ago. It was about 560 km (about 350 mi) long and 240 km (150 mi) wide, had a maximum depth of more than 305 m (1000 ft), and was more than 1525 m (5000 ft) above sea level.

Lake Bonneville

10

Megafaunal Extinctions

Megafaunal Extinctions

Shasta ground slothNothrotheriops shastensis

The stag-moose(scientific name Cervalces scotti)

Megafaunal Extinctions

11

Ancient BisonBison Antiquus

Dwarf PronghornCapromeryx minor

Extinct CamelCamelops hesternus

Megafaunal Extinctions

Columbian Mammoth Mammuthus columbi

American MastodonMammut americanum

Megafaunal Extinctions

Sabertoothed CatSmilodon fatalis

American LionPanthera atrox

Megafaunal Extinctions

12

Dire WolfCanis dirusShort-faced Bear

Arctodus simus

Megafaunal Extinctions

Source: http://www.ucmp.berkeley.edu/mammal/artio/irishelk.html

The Misnamed Extinct “Irish Elk”

~ 4 meters

Holocene Ecology

1. Vegetation Patterns2. Ecological Communities3. Species and Populations

Anthropocene?