Unit 11 – Living on Earth I: Evolution and Extinction

Florissant Fossil Beds National Monument--Gnattily dressed Photos by National

Park Service (indicated) or R. Alley; this is the “Big Stump” fossil redwood.

Unit 11 – Living on Earth I: Evolution and Extinction

The Colorado Rockies Front Range is folded up, perhaps from shallow-subduction drag.

Unit 11 – Living on Earth I: Evolution and Extinction

West of the Front Range are the parks, occupying the low parts of the folds. This is the real South Park, viewed from Wilkerson Pass.

Unit 11 – Living on Earth I: Evolution and Extinction

The real South Park seems to be a nicer place than the one on TV. Here, paintbrush bloom in the mountain air.

Unit 11 – Living on Earth I: Evolution and Extinction

Near the east edge of South Park, Colorado is Florissant Fossil Beds National Monument, one of the little-visited “gems” of the National Park Service.

Unit 11 – Living on Earth I: Evolution and Extinction

Fossil redwoods are among the highlights at the park.

These, including the “Big Stump” (bottom, Natl. Park Service picture) are along the Petrified Forest Loop Trail.

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Unit 11 – Living on Earth I: Evolution and Extinction

http://www.recreation.gov/detail.cfm?ID=2683

“When the mountains are overthrown and the seas uplifted, the universe at Florissant flings itself against a gnat and preserves it.”-- Dr. Arthur C. Peale, Hayden Expedition Geologist, 1873

http://photo.itc.nps.gov/storage/images/flfo/flfo-Full.00004.html

http://www.nature.nps.gov/factsheetarchive/fpaleo.htm

Fossil spider, bee, and leaf, Florissant (National Park Service Photos)

Unit 11 – Living on Earth I: Evolution and Extinction

http://photo.itc.nps.gov/storage/images/flfo/flfo-Full.00006.html National Park Service Photographs. Fossil sumac (left) and hydrangea (right) leaves from Florissant.

Unit 11 – Living on Earth I: Evolution and Extinction

Modern whales evolved from a primitive group of hoofed mammals (top) into species that were progressively more adapted to life in the water (moving downward). Although not every step along the evolutionary path was fossilized, many transitional forms are known, and the progression is clear.

From Teaching about Evolution and the Nature of Science, 1998, National Academy of Sciences, National Academies Press, Washington, DC, http://www.nap.edu, which holds copyright but grants permission for educational use.

The previous slides showed fossils of things slightly different from living types. You really need to put the old and new next to each other to see the changes. Here and in the next picture are a couple of the many, many examples.

Unit 11 – Living on Earth I: Evolution and Extinction

Two figures from FOSSILS, ROCKS, AND TIME, Lucy E. Edwards and John Pojeta, Jr. (right from G. Lynn Wingard) http://pubs.usgs.gov/gip/fossils/intro.html.

(right) Fossils from the Mid-Atlantic States show change through time, from late Cretaceous (late Mesozoic, 6) to Pliocene (late Cenozoic, 1). The shape of the posterior (rear) end of these clams becomes more rounded in the younger species, and the area where the two shells are held together (ligamental cavity) gets larger.

(left) Photographic collage showing evolution of life on Earth through the last 600 million years. The oldest fossils are at the bottom and youngest at the top. The size of each time interval is proportional to its duration; Proterozoic extends beyond 600 million years.