It is undoubtedly true to say that plants do not receive the attention that they deserve. Needless to say this attitude is hardly, a fair one, for plants really do form the basic support of almost all the life on this planet. It is green plants that constitute the major source of energy on land and wherever the light penetrates. Without them, the primitive life forms, with their vast potential for development, would have soon met with extinction.
Most scientists believe that the Earth is about 4.5 billion years old and that life, including photosynthetic organisms, evolved by between 3.5 and 4 billion years ago. These primitive organisms were so simple that they even lacked a nucleus in their single cell. It was not until about 435 million years ago that plant life began to colonize the land.
There are two reasons why plants are worthy of respect and attention. Without them there would be no sustainable source of energy for the life of the planet; without them there would also be no oxygen to shield life from harmful radiation and to provide a means for respiration.
What is a plant?
Plant cell structure usually distinguishes these organisms from animals. A plant is generally considered to be a living organism which manufactures its own food. There are some, however, that are parasitic, and others which are saprophytes, processing food outside their bodies and then absorbing it. Plants are usually immobile, feeding on the spot.
Most scientists believe that the Earth is about 4.5 billion years old and that life, including photosynthetic organisms, evolved by between 3.5 and 4 billion years ago. These primitive organisms were so simple that they even lacked a nucleus in their single cell. It was not until about 435 million years ago that plant life began to colonize the land.
There are two reasons why plants are worthy of respect and attention. Without them there would be no sustainable source of energy for the life of the planet; without them there would also be no oxygen to shield life from harmful radiation and to provide a means for respiration.
What is a plant?
Plant cell structure usually distinguishes these organisms from animals. A plant is generally considered to be a living organism which manufactures its own food. There are some, however, that are parasitic, and others which are saprophytes, processing food outside their bodies and then absorbing it. Plants are usually immobile, feeding on the spot.