primary extinction

См. также в других словарях:

• Cretaceous–Tertiary extinction event — Artist s rendering of bolide impact Badlands nea …   Wikipedia

• Quaternary extinction event — Late Pleistocene landscape of northern Eurasia The Quaternary period saw the extinctions of numerous predominantly larger, especially megafaunal, species, many of which occurred during the transition from the Pleistocene to the Holocene epoch.… …   Wikipedia

• Background extinction rate — Background extinction rate, also known as ‘normal extinction rate’, refers to the standard rate of extinction in earth’s geological and biological history before humans became a primary contributor to extinctions. This is primarily the pre human… …   Wikipedia

• Ecological extinction — Types and definitions of extinctions = Estes, Duggins, and Rathburn (1989) recognize three distinct types of extinction.Global extinction is defined as “the ubiquitous disappearance of a species. [Estes et al. The ecology of extinctions in kelp… …   Wikipedia

• Neanderthal extinction hypotheses — are theories about how Neanderthals became extinct around 30,000 years ago.[1] Since their discovery, both the Neanderthals place in the human family tree and their relation to modern Europeans has been hotly debated. At different times they have …   Wikipedia

• Cascade effect (ecology) — An ecological cascade effect is a series of secondary extinctions that is triggered by the primary extinction of a key species in an ecosystem. Secondary extinctions are likely to occur when the threatened species are: dependent on a few specific …   Wikipedia

• Natural resource — Primary resource redirects here. For original sources used in research, see Primary source. The rainforest on Fatu Hiva, Marquesas Islands is an example of an undisturbed natural resource. Forest provides timber for humans; food and shelter for… …   Wikipedia

• Andrew Jackson: First Annual Message to Congress — ▪ Primary Source              The election of Andrew Jackson in 1828 marked several important changes in American political life. Traditionally, the President had been a member of a previous President s Cabinet, and what is more a man who had… …   Universalium

• Herbert Hoover: Inaugural Address — ▪ Primary Source       Monday, March 4, 1929       This occasion is not alone the administration of the most sacred oath which can be assumed by an American citizen. It is a dedication and consecration under God to the highest office in service… …   Universalium

• Andrew Jackson: On Indian Removal — ▪ Primary Source              Westward expansion brought the United States into contact with numerous Indian tribes, and the admission of new states brought certain Indian lands within the national boundaries. In the following message to Congress …   Universalium

• Abraham Lincoln: A House Divided — ▪ Primary Source       The speech by Abraham Lincoln to the Republican State Convention at Springfield, Illinois, on June 16, 1858, launched his campaign for the U.S. Senate seat held by Stephen A. Douglas. Douglas replied less than a month later …   Universalium