Over 400 thousand species of plants cover our earth. All the green plants in the world have one thing in common – they’re dependent on sunlight for survival. The pigment chlorophyll which gives leaves their green color can capture energy from sunlight. This energy is then put to work converting the plant’s water supply into food. Food is also absorbed through the root system. Dependence on the root system anchors most plants to the earth.
To reproduce themselves they must rely on other life forms, on the weather or on just plain chance. Pollen can be transferred from the male stamen to the female stigma in many different ways. Most flowers have colorful patterns which guide nectar-feeding animals directly to the food source. The resulting seeds can be dispersed over a wide area.
This huge variety of form and structure has evolved over many millions of years from just one group of simple single-celled plants, a group which is still thriving today -- the algae. Plants form the basis of the food chain which makes life possible for higher animals including humans. Certain species of plants can be cultivated to ensure the supply of food. Agriculture forms the basis of settled communities and civilization itself.
Not all plants need direct sunlight to survive. Fungi get nourished from other green plants or from dead matter on the ground. Some, like the starfish fungus, can grow in strange and unexpected ways, but they still need to disperse their seed just like any other plant.
Of all the plant forms on earth, none is more valuable than the many different forms of tree. Coniferous, among the largest plants in the world bear cones instead of flowers. Coniferous forests are cultivated extensively. Flowering, are deciduous trees once covered much of the earth’s surface. During the centuries these great forests have cleared to make way for resettlement, agriculture and later for industry. Continued destruction of the remaining areas of forest alters permanently the delicate relationship between plant life, climate and the earth itself.
They create a rich resource of food and shelter, essential for the continued survival of all life on earth whether humans, animals or other plants.
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