Living Traps (1964)

[Music] it is an established order of nature that animals can survive only by eating material that is living or has lived either other animals or plants green plants on the other hand are able to manufacture their own food from water air minerals and sunlight all plants need nitrogen and in bogs and swamps nitrogen compounds are scarce near the surface of these waters lives the utricle area or a bladder worked it has stems and leaves but no roots the plant does however have tiny traps which can catch animals digest them and thereby obtain the necessary nitrogen the traps are small green bladders animals can get in but they cannot get out the trap is much more than just a one-way door it is an elaborate mechanism with two valves and a trigger which the animal trips eventually the trapped animals die and decompose then special digestive cells lining the trap absorb the food and pass it throughout the plant the pinguicula or Butterworth grows over a large part of North America in swampy soil its leaves are covered with hundreds of small glittering spots which make out of this plant a living flypaper for each of these spots is a sticky glue-like substance that holds any insect that comes in contact with it the sticky substance is secreted by glands on the surface of the leaf when the insect dies other glands secrete a digestive juice which dissolves it there is great variety in these living traps in all of them the traps are not flowers but modified leaves the largest and most beautiful wait for their prey surrounded by orchids in tropical rainforests they are a variety of the pitcher plant called Nepenthes the pitcher itself is colored and looks like a flower around the mouth of the pitcher special cells secrete a nectar which attracts insects insects crawl up the outside of the pitcher and upon reaching the lip crawl down into it then they fall the inside is lined with sharp spikes which point downward the animals lose their footing and fall into a pool of liquid at the bottom of the pitcher the spines pointing down make escape impossible when the insects drown digestive juices and bacteria in the liquid dissolve the bodies and the remains are absorbed by the cells lining the walls of the pitcher a close relative of the tropical pitcher plant is sarracenia the american pitcher plant it is sometimes called frog bonnet or barbed bugle the sundew family is the most common carnivorous group and includes 80 species the leaves of the sundew plant or drosera are covered with tiny red stalked hairs each hair is a gland tipped with a glistening drop of sweet and sticky liquid this liquid can both capture and digest small insects although most carnivorous plants that live in bogs one of them a species of the sundew family the fly catcher lives in extremely dry rocky places the Cape sundew is a miniature gem of nature each drop of liquid is both a lure and a trap while the plant waits for its prey it is motionless only in the delicate tentacles does the living substance of the plant circulate in a perpetual flow plants if they move at all move very slowly but with time-lapse photography the actions that take place in the course of several hours can be compressed into a much shorter time the multitude of glands and fold the victim and simply dissolve it with their secretion which acts like a gastric juice the plant seems almost animal-like in its movements yet there is an essential difference animals move by means of muscles stimulated by nerves a plant has neither muscles nor nerves stimuli are transmitted by means of chemical gradients and motion is performed by the change of the liquid pressure within the cells the struggling insect acts as a stimulus and sets the entire leaf in motion there are varieties of these plants on all continents and they each have adaptations to make up for the nitrogen shortage in the environment [Music] the sundew plant will react in a different manner to contact with digestible material than it does to contact with inorganic substances it cannot use for food a particle of meat is placed on one leaf a piece of cheese on another and a chip of glass on a third the initial stimulus causes the leaves to bend over not only the piece of cheese which contains proteins but over the chip of glass as well the chip of glass is soon released the meat is more similar to the regular food of the plant it sets off the strongest stimulus and the digestive fluids of the glands immediately start dissolving it another member of the sundew family and probably the most well known of all carnivorous plants is the Venus flytrap again it is highly modified leaves which form the trap each half of a leaf is edged with sharp teeth and in the center of the leaf are three short spines when an insect steps on these finds the trap is fun the trap closes in about ten seconds and this is usually fast enough to catch most insects the pressure of the two sides of the leaf is actually strong enough to crush soft bodied animals they have been known to catch small frogs once the trap is closed glands inside secrete digestive juices after about two weeks believe opens again and only the indigestion shell of the insect remains carnivorous plants are only a small part of a living world but they are interesting and colorful for every situation in which life can exist there is an organism which will thrive in that situation their habits show very clearly the immense influence of environment on the development of living things [Music]