It is formed by the set of plants and algae that are part of nature. Despite the diversity of existing species, all plants and algae have one thing in common: they are eukaryotic, multicellular, autotrophic organisms and their reproduction is predominantly sexual.
The plants that inhabit the Earth are relevant for life because photosynthesis releases large amounts of oxygen, becoming the " lungs of the planet ". At the same time, they have a role in feeding other beings, heterotrophs (animals that feed on other living organisms), so that plants represent the first link in the food chain.
The plant kingdom can include plants, algae, fungi, and cyanobacteria. However, the most common classification places algae, fungi, and cyanobacteria in other kingdoms, so the plantae taxon would only include plants.
Members of the kingdom Plantae receive energy from the sun's rays, which they absorb through the chlorophyll of the chloroplasts in their cells. Through photosynthesis, they transform H2O and CO2 into sugars that they use as a source of energy for their subsistence. These living beings also have the ability to feed themselves (they are autotrophs) thanks to minerals, water and substances that they collect from the ground and air.
Generally or customary is that most plants are rooted in the ground, which leads them to not be able to move. However, thanks to their reproduction by spores or seeds, it is possible to spread them to areas far from their original habitat.
The most common theory to explain the origin of current plants are the direct descendants of primitive green algae, with which they share many biological traits, such as the importance of cellulose in its composition or the presence of certain photosynthetic pigments.
In this kingdom are grouped almost half a million species of plants that populate all corners of the Earth, from the sands of the Sahara desert to the tropical forests of South America. However, all of these plants can be classified into four main divisions: bryophytes, pteridophytes, gymnosperms, and angiosperms.
- The first of these divisions, the bryophytes, includes the most primitive plants, such as mosses and liver plants.
- The second group, that of pteridophytes, is made up of those plants that reproduce by spores, such as ferns.
- To finish the angiosperms, as with the plants of the previous group, they also reproduce by seeds, but in this case, they are confined within a fruit, as in flowering plants.
