Biology Unit 5 DB Essay Example | Topics and Well Written Essays - 500 words

Biology Unit 5 DB - Essay Example The leaves grow from a basal rosette, and a ‘keel’ provided the required structural reinforcement to each pitcher so the the opening is always upright. Foraging, flying or crawling insects such as flies are attracted to the cavity formed by the cupped leaf, often by visual lures such as anthocyanin pigments, and nectar bribes. The sides of the pitcher are slippery and may be grooved in such a way so as to ensure that the insects cannot climb out. The small bodies of liquid contained within the pitcher traps are called phytotelmata. They drown the insect, and the body of it is gradually dissolved. This may occur by bacterial action (the bacteria being washed into the pitcher by rainfall) or by enzymes secreted by the plant itself. Furthermore, some pitcher plants contain mutualistic insect larvae, which feed on trapped prey, and whose excreta the plant absorbs (Wikipedia). During digestion, trapped prey are converted into a solution of amino acids, peptides, phosphates, ammonium and urea. The plant obtains its mineral nutrition, particularly nitrogen and phosphorus, from this solution. Common habitats of the pitcher plant are bogs, savannas and flat woods. The wettest parts of the bogs are favored, often restricting the species to the edge of the bogs. Pitcher plants form dense floating mats on the water on the edge of bog ponds or lakes and acidic streams. The carnivorous form of nutrition of the plant is an adaptation to the poor mineral content or acidic nature of the soil in which it grows. The soil in which it grows is usually deficient in trace elements such as molybdenum. Such soils are usually highly acidic and unsuitable for many other plants. The modified leaves of the pitcher plant help it to catch preys that comprise not only insects but also isopods, mites, spiders and the occasional frogs. What the plant does not get from the soil it grows in, it obtains from the living prey it catches