sundews is the plant whose leaves close when you touch it.
plant that leaves close when you touch it?
sundews
thigmonastic movements, those that occur in response to touch, are used as a defense in some plants. the leaves of the sensitive plant, "mimosa pudica", close up rapidly in response to direct touch, vibration, or even electrical and thermal stimuli. the proximate cause of this mechanical response is an abrupt change in the turgor pressure in the pulvini at the base of leaves resulting from osmotic phenomena. this is then spread via both electrical and chemical means through the plant; only a single leaflet need be disturbed. this response lowers the surface area available to herbivores, which are presented with the underside of each leaflet, and results in a wilted appearance. it may also physically dislodge small herbivores, such as insects.
plant defense against herbivory
in order for an organism to "escape", and then radiate into varying species it needs a mechanism to escape. these defense mechanisms vary widely and differ for different types of organisms. plants use chemical defenses in the form of secondary metabolites or allelochemicals. these allelochemicals inhibit the growth, behavior, and health of herbivores, allowing plants to escape. an example of a plant allelochemical are alkaloids that can inhibit protein synthesis in herbivores. other forms of plant defense include mechanical defenses such as thigmonasty movements which have the plant leaves close in response to tactile stimulation. indirect mechanisms plant include shedding of plant leaves so less leaves are available which deters herbivores, growth in locations in that are difficult to reach, and even mimicry. for organisms other than plants, examples of defense mechanisms allowing for escape include camouflage, aposematism, heightened senses and physical capabilities, and even defensive behaviors such as feigning death. an example of an organism using one of these defense mechanisms is the granular poison frog which defends itself through aposematism. it is important to understand that in order for escape and radiate coevolution to occur, it is necessary that the developed defense is novel rather than previously established.
escape and radiate coevolution