Carnivorous plants
Plants do not actually eat. They get their energy from sunlight through photosynthesis. However, in addition to energy, they need minerals and nutrients, including nitrogen. Most plants get them dissolved in water through their roots. Nitrogen is particularly important for the formation of enzymes and other proteins. But in areas with very nutrient-poor soils, such as marshes or sandy soils, nitrogen is so scarce that plants have to resort to other tricks.
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These plants have leaves where animals (mainly insects and other small creatures) are trapped or get stuck so that nutrients (nitrogen, phosphorus, etc.) can be absorbed by the plant. Although simplified, we call these plants 鈥榗arnivorous鈥�.
There is a wide variation in the trapping leaves of these plants. The leaves may simply be sticky and have enzymes that dissolve the insect. Others have leaves with underwater trapping bladders that small animals are sucked into if they get too close, or actively catching insects that touch them (such as the venus flytrap). Others have more intricate jug-formed leaves that insects are lured to and fall into (fly trumpets). There are other variations and combinations of trapping methods.
This way of obtaining nutrients has arisen several times through evolution in different groups of plants. The oldest evolutionary lineages of so called carnivorous plants have been dated to be more than 80 million years old, but other lineages are much younger.