First of all, what is a plant? A plant cannot be defined in a statement without excluding some plants, or including some animals. A plant is characterized by being able to produce its own food from water, minerals, and carbon dioxide from a process known as photosynthesis. Photosynthesis uses the energy from sunlight and changes it to a form the plant can use, with the help of chlorophyll, a green pigment molecule in a plant that converts light energy into a form of energy that the plant can use. The lack of nervous and sensory systems and the lack of organs of locomotion also characterize a plant.
But there are plants that do not follow these simple rules. Some plants, for example, are not green and do not produce their own food by photosynthesis but are dependent on other plants for their food. Some plants have limited powers of movement. So from this you can conclude that the difference between plants and animals is vague, especially among the more primitive forms.
Plant organs are organized into three kinds of organs: roots, stems, and leaves. Roots anchor the plant into the ground and they also gather minerals and water from the ground. Roots usually grow under ground and downward. Roots have tiny “hairs” which increase the surface of the roots, which results in more gathering of minerals and water. Stems are usually above ground, grow upward, and usually have leaves. Plants that do not have leaves generally use the stem as the photosynthetic surface, like cacti. Leaves are still the most common photosynthetic surface on plants, though. Leaves absorb carbon dioxide and release oxygen. Some leaves of plants have spines or thorns to provide them with protection from animals. Certain types of plants have highly modified leaves to trap and digest insects, known as insectivorous plants.
Most plants exist have separate male and female parts. Pollen from the male part must reach the female part in order for pollination to take place. Wind can pollinate plants, but it is usually animals, such as bats, insects, or birds. Plants sometimes rely on bait to get these animals to come. Some animals might be attracted to the fruit of trees, which hold the seeds.
Some plants have evolved to depend upon other organisms. Yet some plants have evolved to compete with other animals, or even other plants. These plants may grow higher than the surrounding plants so that it can get more sunlight. Plants may become parasitic and use another plant’s resources. Many plants produce germination preventing chemicals.
Plants have been around a very long time, and ever since there were animals, some of those animals have been dependent upon plants for food. Wheat, corn, and rice are the most used plants as far as food. But Humans today are also dependent upon plant for many reasons, not just for food. We make furniture and shelters out of wood, and we make clothes out of cotton. Plants provide us with paper. Paper can be dated back to 105 AD in China. Drugs made from plants are essential to some people’s health and if those plants were not in existence, it could mean a huge difference in our world. Fossil fuels would not be here if there weren’t any plants around. Whole economies of some countries depend on plants. Plants were, and still are, important in life.
Plants do more than just provide resources for us. They modify climates and hold soil in place, which lessens the impact of erosion. Plants produce oxygen as a waste product of the carbon dioxide that we breathe out. If either one would cease to be, the other would follow shortly.