Changes

About 350,000 [[species]] of plants, defined as [http://en.wikipedia.org/wiki/Seed_plant seed plants], [http://en.wikipedia.org/wiki/Bryophyte bryophytes], [http://en.wikipedia.org/wiki/Fern ferns] and [http://en.wikipedia.org/wiki/Fern_allies fern allies], are estimated to exist currently. As of 2004, some 287,655 species had been identified, of which 258,650 are [http://en.wikipedia.org/wiki/Flowering_plant flowering plants], 16,000 [http://en.wikipedia.org/wiki/Bryophyte bryophytes], 11,000 [http://en.wikipedia.org/wiki/Fern ferns] and 8,000 [http://en.wikipedia.org/wiki/Green_algae green algae]

About 350,000 [[species]] of plants, defined as [http://en.wikipedia.org/wiki/Seed_plant seed plants], [http://en.wikipedia.org/wiki/Bryophyte bryophytes], [http://en.wikipedia.org/wiki/Fern ferns] and [http://en.wikipedia.org/wiki/Fern_allies fern allies], are estimated to exist currently. As of 2004, some 287,655 species had been identified, of which 258,650 are [http://en.wikipedia.org/wiki/Flowering_plant flowering plants], 16,000 [http://en.wikipedia.org/wiki/Bryophyte bryophytes], 11,000 [http://en.wikipedia.org/wiki/Fern ferns] and 8,000 [http://en.wikipedia.org/wiki/Green_algae green algae]

The [[photosynthesis]] conducted by land plants and algae is the [[ultimate]] [[source]] of [[energy]] and [[organic]] [[material]] in nearly all [[ecosystems]]. Photosynthesis [[radically]] changed the [[composition]] of the early [[Earth]]'s [[atmosphere]], which as a result is now 21% [http://en.wikipedia.org/wiki/Oxygen oxygen]. [[Animals]] and most other [[organisms]] are aerobic, relying on oxygen; those that do not are confined to [[relatively]] rare anaerobic [[environments]]. Plants are the primary producers in [[most]] [[terrestrial]] [[ecosystems]] and form the basis of the [[food]] web in those ecosystems. Many [[animals]] rely on plants for shelter as well as oxygen and food.

The [[photosynthesis]] conducted by land plants and algae is the [[ultimate]] [[source]] of [[energy]] and [[organic]] [[material]] in nearly all [[ecosystems]]. Photosynthesis [[radically]] changed the [[composition]] of the early [[Earth]]'s [[atmosphere]], which as a result is now 21% [http://en.wikipedia.org/wiki/Oxygen oxygen]. [[Animals]] and most other [[organisms]] are aerobic, relying on oxygen; those that do not are confined to [[relatively]] rare anaerobic [[environments]]. Plants are the primary producers in [[most]] [[terrestrial]] [[ecosystems]] and form the basis of the [[food]] web in those ecosystems. Many [[animals]] rely on plants for shelter as well as oxygen and food.