Viridiplantae
Encyclopedia
Viridiplantae are a clade
comprising the green algae and land plants.
In some classification systems they have been treated as a kingdom
, under various names, e.g. Viridiplantae, Chlorobionta, or simply Plantae, the latter expanding the traditional Plant Kingdom
to include the green algae
. Adl et al., who produced a classification for all eukaryote
s in 2005, introduced the name Chloroplastida for this group, reflecting the group having primary chloroplast
s with green chlorophyll
. They rejected the name Viridiplantae on the grounds that most of the species are not plants, as understood traditionally.
Together with Rhodophyta
and glaucophyte
s, Viridaeplantae are thought to belong to a larger clade called Archaeplastida
or Primoplantae.
The monophyletic Chlorophyta
and Streptophyta are classified under Viridiplantae.
There are more than 350,000 species of Viridiplantae.
A taxonomic evaluation of eukaryote
s based on myosin
distribution showed that Viridiplantae lost class-I myosins.
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
comprising the green algae and land plants.
In some classification systems they have been treated as a kingdom
Kingdom (biology)
In biology, kingdom is a taxonomic rank, which is either the highest rank or in the more recent three-domain system, the rank below domain. Kingdoms are divided into smaller groups called phyla or divisions in botany...
, under various names, e.g. Viridiplantae, Chlorobionta, or simply Plantae, the latter expanding the traditional Plant Kingdom
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
to include the green algae
Green algae
The green algae are the large group of algae from which the embryophytes emerged. As such, they form a paraphyletic group, although the group including both green algae and embryophytes is monophyletic...
. Adl et al., who produced a classification for all eukaryote
Eukaryote
A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear...
s in 2005, introduced the name Chloroplastida for this group, reflecting the group having primary chloroplast
Chloroplast
Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis.Chloroplasts are green...
s with green chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
. They rejected the name Viridiplantae on the grounds that most of the species are not plants, as understood traditionally.
Together with Rhodophyta
Red algae
The red algae are one of the oldest groups of eukaryotic algae, and also one of the largest, with about 5,000–6,000 species of mostly multicellular, marine algae, including many notable seaweeds...
and glaucophyte
Glaucophyte
The glaucophytes, also known as glaucocystophytes or glaucocystids, are a small group of freshwater microscopic algae. Together with the red algae and green algae plus land plants , they form the Archaeplastida...
s, Viridaeplantae are thought to belong to a larger clade called Archaeplastida
Archaeplastida
The Archaeplastida are a major group of eukaryotes, comprising the red and green algae and the land plants, together with a small group called the glaucophytes. The plastids of all of these organisms are surrounded by two membranes, suggesting they developed directly from endosymbiotic...
or Primoplantae.
The monophyletic Chlorophyta
Chlorophyta
Chlorophyta is a division of green algae, informally called chlorophytes. The name is used in two very different senses so that care is needed to determine the use by a particular author...
and Streptophyta are classified under Viridiplantae.
There are more than 350,000 species of Viridiplantae.
A taxonomic evaluation of eukaryote
Eukaryote
A eukaryote is an organism whose cells contain complex structures enclosed within membranes. Eukaryotes may more formally be referred to as the taxon Eukarya or Eukaryota. The defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus, or nuclear...
s based on myosin
Myosin
Myosins comprise a family of ATP-dependent motor proteins and are best known for their role in muscle contraction and their involvement in a wide range of other eukaryotic motility processes. They are responsible for actin-based motility. The term was originally used to describe a group of similar...
distribution showed that Viridiplantae lost class-I myosins.