Carnivorous plant

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The primitive pitchers of Heliamphora chimantensis are an example of pitfall traps.
Sticky glands and tentacle movement on Drosera capensis
The Venus flytrap: shows reaction to the second touch.

Carnivorous plants are plants which get nutrients from trapping and eating animals. They are often called insectivorous plants, because they usually trap insects. Since they get some of their food from animals, carnivorous plants can grow in places where the soil is thin, or poor in nutrients. This is true for soils with little nitrogen, such as acidic bogs and rock outcrops. Charles Darwin wrote the first well-known book on carnivorous plants in 1875.Closing </ref> missing for <ref> tag It must then also benefit from digesting the prey. In most cases, this will yield amino acids and ammonium ions. There are some cases, where plants catch the prey, but they do not digest it. Rather, they have a symbiosis with another organism, which feeds on the prey. One such case is the species of the sundew Roridula, which forms a symbiosis with the assassin bug. The bugs eat the trapped insects. The plant benefits from the nutrients in the bugs' faeces.[1]

Evolution[change | change source]

Artist's view of Archaeamphora, the earliest known carnivorous plant

Few fossil carnivorous plants have been found, and then usually as seed or pollen. Carnivorous plants are generally herbs, without wood or bark. True carnivoury has probably evolved independently at least six times.[2]

Some think all trap types have a similar basic structure—the hairy leaf.[3] Hairy leaves do catch and hold drops of rainwater, which helps bacterial growth. Insects land on the leaf, are caught by the surface tension of the water, and suffocate. Bacteria start to decay the insect, and release nutrients from the corpse. The plant then absorbs the nutrients through its leaves. This 'leaf feeding' can be found in many non-carnivorous plants. Plants that were better at holding water and insects therefore had a selective advantage. Rainwater can be retained by cupping the leaf, leading to pitfall traps. Alternatively, insects can be caught by making the leaf stickier, leading to flypaper traps.

References[change | change source]

  1. Hartmeyer, S. (1998). "Carnivory in Byblis revisited II: The phenomenon of symbiosis on insect trapping plants". Carnivorous Plant Newsletter 27 (4): 110–113. http://www.carnivorousplants.org/cpn/samples/Science274Byblis2.htm. 
  2. Albert V.A. Williams S.E. and Chase M.W. 1992. Carnivorous plants: phylogeny and structural evolution. Science 257: 1491–1495.
  3. Slack A (1988). Carnivorous plants. London: Alphabooks. pp. 18–19. ISBN ISBN 0-7136-3079-5 Check |isbn= value: invalid character (help).