A plant is a living organism that grows on the earth and belongs to the kingdom Plantae. They are predominantly photosynthetic, meaning they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with cyanobacteria to produce sugars from carbon dioxide and water, using the green pigment chlorophyll. Plants are multicellular organisms that can be distinguished from other living things by a number of characteristics:
- They make their own food. Plants are photosynthetic and contain a green pigment called chlorophyll, which enables plants to convert energy from the sun into food. Plants store their food as starch.
- Most plants are rooted to one place – some plants can orientate leaves towards the sun and some respond to touch.
- Plants are essential for any ecosystem. They provide all the energy for the ecosystem, because they can get energy directly from sunlight.
Plants range in size from diminutive duckweeds only a few millimeters in length to the giant sequoias of California that reach 90 meters or more in height. There are an estimated 390,900 different species of plants known to science, and new species are continually being discovered.
