1 / 4

THEORIES OF MASS EXTINCTION Defining concepts and theories

THEORIES OF MASS EXTINCTION Defining concepts and theories. Concepts. Extinction All living individuals of a type (species) have died out and do not exist anywhere on earth. Mass extinctions Periods of time when almost all of the life on Earth died out. Why extinctions?

jeri
Download Presentation

THEORIES OF MASS EXTINCTION Defining concepts and theories

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. THEORIES OF MASS EXTINCTIONDefining concepts and theories

  2. Concepts • Extinction • All living individuals of a type (species) have died out and do not exist anywhere on earth. • Mass extinctions • Periods of time when almost all of the life on Earth died out. • Why extinctions? • Environmental disasters (e.g. meteor/ asteroid impacts, severe volcanism, cosmic radiation (exploding stars, super-lethal diseases ) • Failure to adapt to habitat or environmental changes (e.g. fluctuating ice/ warm ages, global sea level changes, continental drift )

  3. THEORIES OF MASS EXTINCTION • Continental drift • The movement of separate parts of the earth’s crust (continental plates) over a period of time • Alex du Toit, world famous S,African geologist, pioneered this theory in 1937 in his book “Our wandering continents” 1996-2007 EnchantedLearning.com

  4. CLIMATE CHANGE 1. Cooling of the atmosphere • Ice age • The cooling of the earth and the formation of glaciers that covers a part of the earth’s surface for a period of time • Formation of glaciers causes: • Ocean levels to drop (due to water trapped in glaciers, as ice) • Decrease in O2 levels • Increase in salt (mineral) content of ocean • Change in natural environments

More Related