We all live among them, but I do not think many of us realize what plants can do for us. However, until the unit on Plants in my Biology class, I wasn??t aware either. What at first may seem like a bore can actually be quite interesting. You should take it from me; I had to spend over a month talking about plants.
Perhaps you know about photosynthesis, which is the use of light energy (from a source like the sun) to convert carbon dioxide and water into carbohydrates (like sugars) that the plant will then use for food and nourishment.
The basic requirements for plants are light, water, and soil nutrients so that they can grow. However, many environments lack one or more of these requirements. Therefore, plants have to adapt to certain requirements to deal with these less-than-ideal conditions. For example, plants that live in desert areas must find ways to conserve water and prevent dehydration. The cactus is an example of a plant that is able to do so. It has needles instead of leaves, since needles reduce the surface area and that helps to prevent water loss. Cactus plants go through photosynthesis in their stems, since their needles are too small to do so. They have thick stems that are adapted to help store more water.
Plants that live in areas with nutrient-poor soil have to adapt to very acidic environments. Did you know that there is such thing as a carnivorous plant? Carnivorous means that the plant eats other insects to consume its food. Plants need nitrogen to survive, and areas with acidic soil lack the nitrogen plants need. The sundew, pitcher plant, and butterwort are all examples of carnivorous plants. They capture, kill, and digest part of the insects. They consume all of the insect??s nitrogen and then the remainder of the animal is then discarded. The Venus flytrap is a plant that has hair-like triggers on its opening that closes shut when an insect enters it.
Have you ever heard of a tropism? Basically, what it is, is plant growth in response to its environment (or, using a scientific term, an external stimulus). Gravitropism refers to plant growth in response to gravity. If gravity pushes down on the plant, then the plant is likely to grow in a downward direction.
Thigmotropism is plant growth in response to touch. If you touch a certain plant sharply, it will begin to grow in the direction opposite of your touch. For example, if you touch the plant on its left side, it would most likely grow in the right direction.
Chemotropism is plant growth in response to certain chemicals. For example, tomatoes are given certain chemicals that help speed up the ripening process. This is so they arrive ripe at the grocery store just in time for the tomatoes to be bought by the consumers.
I hope that you are still reading this, and I have not bored you or frightened you with this information. They say your day has not been a complete waste if you manage to learn something you didn??t know beforehand.
Did I change your perception of plants? I hope that I did! However, do not fret! I don??t have any Greenpeace signs I can bring out and walk around Whyville with!
Gotta Get Through This,
Biology 11, Published by Addison Wesley, 2000.