Rapid plant movement slower "growth-movements" of plants, called tropisms. Tropisms encompass movements that lead to physical, permanent alterations of the plant while rapid plant movements are usually reversible or occur at over a shorter span of time. A variety of mechanisms are utilized by plants in order to achieve these fast movements. Extremely fast movements such as the explosive spore dispersal techniques of "Sphagnum" mosses may involve increasing internal pressure via dehydration, causing a sudden propulsion of spores up or through the rapid opening of the "flower" opening triggered by insect pollination. Fast movement can also be expressed in predatory plants, where the
What Work Is What Work Is What Work Is is a collection of poetry by Philip Levine. The collection has many themes that are representative of Levine's writing including physical labor, class identity, family relationships and personal loss. Its primary focus on work and the working class led to it being studied with emphasis on Marxist literary criticism. The focus on work is expressed in thematically different ways throughout the collection. Furthermore, much of the collection was shaped by concerns for blue collar workers as well as nationwide political events. "What Work Is" was first published in 1991 by Alfred A. Knopf, Inc.