By Alea DelleCave
I. intro:
Carnivores have roamed the planet for centuries, but lately researchers have been gathering information on the carnivores that cant roam...like plants for example. Some plants have the ability to hunt and kill without actually moving. Some have sticky petals, thorns, or snapping traps, they gain all of their nutrients from consuming animals, mostly insects or small crawlers. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic bogs and rock outcroppings. Charles Darwin wrote Insectivorous Plants, the first well-known treatise on carnivorous plants, in 1875. True carnivore's were thought to have evolved independently six times in five different orders of flowering plants, and these are now represented by more than a dozen genera. These include about 630 species that attract and trap prey, produce digestive enzymes, and absorb the resulting available nutrients. Additionally, over 300 protocarnivorous plant species in several genera show some but not all these characteristics.
II. discovery:
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| Pc1. A grasshopper caught in the Venus Fly Trap |
Venus Fly Traps are the most well known carnivorous plant, famous for their quickly closing "jaw" they can trap trey and slowly devour it. It has the ability to sense by having three 'trigger hairs" on the north and south parts of the lobes. When a trigger hair is bent, stretch-gated ion channels in the membranes of the cells at the base of the trigger hairs open up, generating on action potential that propagates to cells in the mid rib. The cells respond by pumping more ions out, which can cause water to flow by osmosis, collapsing the cells within the midrib, or cause rapid acid growth, which paralyzes and kills the animal. How this is done is still debated, but still ends in the same result: a quick flash and a snap of the jaw. This whole process takes less then a second. The more the insect struggles the tighter the jaw becomes. The jaw then transforms into a stomach and digestion occurs over a period of 2 weeks.
The Sundew: Beauty and Bite
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| Pc2. A sundew |
Sundews are beautiful structures that are characterised by the glandular tentacles, topped with sticky secretions, that cover their laminae. The trapping and digestion mechanism usually employs two types of glands: stalked glands that secrete sweet mucilage to attract insects and enzymes to digest them, and sessile glands absorb the resulting "nutrient soup".Upon touching the sticky dew, the prey becomes entrapped by sticky mucilage which prevents their progress or escape. Eventually, the prey either succumb to death through exhaustion or through asphyxiation as it envelops them and suffocates them. Death usually occurs within one quarter of an hour. The plant them sends out enzymes to both dissolve the insect and free the contained nutrients. The nutrient soup is then absorbed through the leaf surface and can then be used to help fuel plant growth.
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| Pc3. A Sundew Captures his prey |
All species of sundew are able to move their tentacles in response to contact with digestible prey. The tentacles are extremely sensitive and will bend toward the center of the leaf in order to bring the insect into contact with as many stalked glands as possible. According to Charles Darwin, the contact of the legs of a small gnat with a single tentacle is enough to induce this response. In addition to tentacle movement, some species are able to bend their laminas to various degrees in order to maximize contact with the prey.
Nepenthes truncata: Natures own Slip and Slide
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| Pc.4 A mouse is found! |
We currently know very little about the Nepenthes Truncata. Its inner lining of its tube shaped opening and neck are lined with an extremely slippery substance where once a critter has stepped even the slightest bit to close, it will fall in and become prey. At the bottom of the plant it collects a water-like substance which seems to attract insects, as well as mice. Its the only recorded plant that has successfully devoured a mammel bigger then a grasshopper or bumble bee.
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| pc.5 the mouse and his decaying body.. |
The Bladderwort: The underwater vacuum
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| pc6. This is the Bladderwort |
The trapping mechanism of The Bladderwort is purely mechanical. There is no sence from the plant, irritability, that is required in the presence of prey.
As water is pumped out ,because it is an underwater plant, the bladder's walls are sucked inwards by the partial vacuum created, and any dissolved material inside the bladder will become more concentrated. The sides of the bladder bend inwards, storing potential energy. Soon, no more water can be gained, and the bladder trap is good and ready.
Extending outwards from the bottom of the trapdoor are several long bristle-stiff protuberances that are sometimes referred to as trigger hairs, but which have no similarity to the sensitive triggers found on other plants. These bristles are simply levers, the force of the suction exerted by the primed bladder on the door is resisted by the adhesion of its flexible bottom against the soft-sealing velum. T
he bladder walls spring back to a more rounded shape; the door flies open and a column of water is sucked into the bladder. The animal which touched the lever, if small enough, is inevitably drawn in, and as soon as the trap is filled, the door resumes its closed position. The whole operation being completed in as little as one-hundredth of a second
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| pc7. The Shell of the Bladderwort |
Once inside, the prey will be dissolved by digestive secretions. This generally occurs within a few hours, although some protozoa appear to be highly resistant and have been observed to live for several days inside the trap. All the time, the trap walls continue to pump out water, and the bladder can be ready for its next capture in as little as 15 to 30 minutes.
III. biography of investigator:
Charles Darwin, was the first to look into the idea of carnivorous plants. In 1860, soon after he encountered his first carnivorous plant, the sundew Drosera, he wrote, "I care more about Drosera than the origin of all the species in the world." He spent months running experiments on the plants. He dropped flies on their leaves and watched them slowly fold their sticky tentacles over their prey. He excited them with bits of raw meat and egg yolk. He marveled how the weight of just a human hair was enough to initiate a response. Yet sundews ignored water drops, even those falling from a great height.
IV. impact on hummanity:
The discovery of plants with a thirst for blood has given scientist a whole new realm of diet possibilities for plants today, and ones who are today extinct. Given the fact that plants cannot move, and are stuck in one place it is unbelievable that they have the ability to catch their own prey. These plants get their nutrients from the bugs they eat, but gain energy from the sun, like the average plant. The evolution of carnivorous plants is obscured by the past of their fossil record. A lot can be deduced from the structure of todays traps. There are over a quarter of a million species of flowering plants. Of these, only around 630 are known to be carnivorous. True carnivory has probably evolved independently at least six times, however, some of these "independent" groups probably descended from a recent common ancestor with a predisposition to carnivory. It has been suggested that all trap types are modifications of a similar basic structure—the hairy leaf. The Bacteria jumpstart decay, releasing from the corpse nutrients that the plant can absorb through its leaves.
http://www.youtube.com/watch?v=uJpgMDOZInA
(the instant video wouldnt work. but this is the best video by far)
V. Journal Entry
Carnivorous Plants
By: Alexander Volkov
Today's biologists are using 21st-century tools to study cells and DNA. they are beginning to understand how these plants hunt, eat, and digest. as well as how these bizarre adaptations arose in the first place. After years of study, Alexander Volkov, a plant physiologist at Oakwood University in Alabama, believes that he has figured out the Venus flytrap's secret. "This," Volkov declares, "is an electrical plant."
Volkov's experiments reveal that the charge travels down fluid-filled tunnels in a leaf, which opens up pores in cell membranes. Water surges from the cells on the inside of the leaf to those on the outside, causing the leaf to rapidly flip in shape from convex to concave, like a soft contact lens. As the leaves flip, they snap together, trapping an insect inside.
The bladderwort has an equally sophisticated way of setting its underwater trap. It pumps water out of tiny bladders, lowering the pressure inside. When a water flea or some other small creature swims past, it bends trigger hairs on the bladder, causing a flap to open. The low pressure sucks water in, carrying the animal along with it. In one five-hundredth of a second, the door swings shut again. The cells in the bladder then begin to pump water out again, creating a new vacuum.
a pitcher plant that grows in jungles on Borneo, produces nectar that both lures insects and forms a slick surface on which they can't get a grip. Insects that land on the rim of the pitcher hydroplane on the liquid and tumble in. The digestive fluid in which they fall has very different properties. Rather than being slippery, it's gooey. If a fly tries to lift its leg up into the air to escape.
Volkov's experiments reveal that the charge travels down fluid-filled tunnels in a leaf, which opens up pores in cell membranes. Water surges from the cells on the inside of the leaf to those on the outside, causing the leaf to rapidly flip in shape from convex to concave, like a soft contact lens. As the leaves flip, they snap together, trapping an insect inside.
The bladderwort has an equally sophisticated way of setting its underwater trap. It pumps water out of tiny bladders, lowering the pressure inside. When a water flea or some other small creature swims past, it bends trigger hairs on the bladder, causing a flap to open. The low pressure sucks water in, carrying the animal along with it. In one five-hundredth of a second, the door swings shut again. The cells in the bladder then begin to pump water out again, creating a new vacuum.
a pitcher plant that grows in jungles on Borneo, produces nectar that both lures insects and forms a slick surface on which they can't get a grip. Insects that land on the rim of the pitcher hydroplane on the liquid and tumble in. The digestive fluid in which they fall has very different properties. Rather than being slippery, it's gooey. If a fly tries to lift its leg up into the air to escape.
- http://ngm.nationalgeographic.com/2010/03/carnivorous-plants/zimmer-text/3
- http://en.wikipedia.org/wiki/Carnivorous_plant#Evolution
- http://www.sarracenia.com/faq.html
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