Introducing the Planet: The Earth Before Humans. Climate and Weather Ecosystems and Eco-regions Biodiversity. Climate and Weather . Lands near the equator are, on average, warmer. Closer to either pole and the earth is colder.
Selected World Climographs
ATropical Wet, hot equatorial regions, that cover about a third of Earth’s surface. Rains nearly every day. No or little seasonality. Precipitation around 80-100” annually. Frequent thunderstorms. Hurricanes.
BDry Arid and semi-arid deserts and steppes; evaporation exceeds precipitation. U.S. example: Albuquerque, New Mexico (annual precipitation, 22 cm [9 inches]). Rain falls as infrequent, but powerful, summer thunderstorms.
CMesothermal Humid subtropical, may have dry summers. Warmest month above 10oC (50oF); coldest month above 0oC (32oF) but below 18oC (64oF). U.S. example, New Orleans, Louisiana. Mid-latitude storms and thunderstorms common.
DMicrothermal Humid climate with long winters, mild summers. Warmest month above 10oC (50oF); coldest month below 0oC (32oF). U.S. example, Flint, Michigan. Most rain falls in mid-latitude frontal storms.
EPolar No true summer, warmest month average temperatures below 10oC (50oF); always cold. U.S. example, Barrow, northern Alaska. Very short growing season. No thunderstorms.
HHighland Lower temperatures and more precipitation. U.S. example, Blue Canyon, Sierra Nevada, California (annual precipitation, 170 cm [68 inches]). Very short growing season.
A biome is a major class of ecologically similar communities of plants, animals, and soil organisms, often referred to as ecosystems. Biomes are defined based on factors such as plant structures (such as trees, shrubs, and grasses), leaf types (such as broadleaf and needleleaf), plant spacing (forest, woodland, savanna), and other factors like climate. Biomes are often identified with particular patterns of ecological succession and climax vegetation.
Boreal Forest (Taiga)
World Biomes (Click title for photographs and descriptions)
Occurs after disturbances: fires, storms, landslides, etc.
Vegetation that grows along water courses.
Often supports much richer diversity of plant and animal life, including more trees in a dry environment.
Sespe Wilderness near Ojai, CA
Energy flows up the chain as more and more heat is lost at each trophic level.
Ecosystems: Food Web
“Now when you cut a forest, an ancient forest in particular, you are not just removing a lot of big trees and a few birds fluttering around in the canopy. You are drastically imperiling a vast array of species within a few square miles of you. The number of these species may go to tens of thousands. ... Many of them are still unknown to science, and science has not yet discovered the key role undoubtedly played in the maintenance of that ecosystem, as in the case of fungi, microorganisms, and many of the insects.” (E. O. Wilson, 2000)
Biodiversity refers to diveristy of
% of Genera Extinct in Period
Millions of Years Before Present
Source: Rohde, R.A. & Muller, R.A. (2005). "Cycles in fossil diversity". Nature434: 209-210.
•Mosquito fish (Australia from SE U.S.)
•Zebra mussel (U.S. from Asia)
•Kudzu (U.S. from Asia)
•Asian long-horned beetle (U.S. from China)
•Rosy wolfsnail (Hawaii from U.S. Mainland)
•Cane toad (Australia)
•Bullfrog (United States from U.S.)
•Gypsy moth (United States from Europe))
• European starling (U.S. from Shakespeare!)
• Indian mongoose (Hawaii)
•Caulerpa algae (CA from aquariums)
•Cheatgrass (United States from Europe)
•Brown tree snake (Guam from Australia)
(too much hunting, fishing…)
(too much timber cutting, fossil fuel use…)
Monteverde Golden Toad, Last seen 1989
The Encyclopedia of Life – http://eol.org
E.O. Wilson on the Value of Biodiversity (PBS Bill Moyers Journal)