Iris folding is a paper craft technique that involves folding strips of colored paper in such a way to form a design.The center of the design forms an iris â a shape reminiscent of the iris diaphragm of a camera lens.istory [edit]. Iris folding originated in Holland, where early craft people made their designs using patterned paper cut from the inside of envelopes. Today, crafters use any light weight paper, such as scrapbook paper, origami paper, wrapping paper, the inside of envelopes or pages of magazines. Ribbon is also used.
Extinction is the disappearance of a previously learned behavior when the behavior is not reinforced. In this lesson, learn more about extinction in operant conditioning and test your knowledge with a quiz.
Although extinction is a natural process, the rate at which current extinction is taking place is clearly not, and all scientific evidence indicates that the activities of man kind are the primary engine behind most recent and present extinction events. Major causes of extinction include: Habitat Loss Destructive change to environments or landscapes, either through natural phenomena (such as floods, volcanoes, hurricanes etc.), or human processes (such as construction, deforestation, changing landuse for agriculture, artificial land drainage etc.), is the single greatest threat to the biodiversity of Planet Earth, and the greatest cause of extinction in our world.