In the classification of living beings there is a structure differentiated by kingdoms: the Monera Kingdom, the Protista, the Fungi, the Animalia and the Plantae Kingdom.
The Kingdom plantae 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 something in common: they are eukaryotic, multicellular, autotrophic organisms and their reproduction is predominantly sexual.
Generations and constant evolutions of a wonderful world
A very unique characteristic of plants is that they present alternation of generations, this means that the plant is diploid in one stage of its life and in another it is aploid.
The importance of plants in the ecosystem: photosynthesis and the food chain
The plants that inhabit the Earth are relevant for life because through photosynthesis they release large amounts of oxygen, which is why they become 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 plants represent the first link in the food chain.
Evolution of Kingdom plantae
As for the origin of plants, it is believed that evolutionarily they come from algae in the aquatic environment and their subsequent transformation throughout evolution.
There is an agreement among biologists that the first plants on Earth were bryophytes, which left the water and established themselves on the continent through a series of adaptations. Over time, larger and more evolved plants colonized the Earth's surface. In this process, at the end of the Paleozoic era, large fern forests were formed and later the higher plants appeared.
Plant structure, from simplicity to complexity
This evolution of the Kingdom Plantae can be seen in the structure of the various plants. At a first level of complexity, bryophytes are very simple and do not have conductive vessels, so they live near water, while pteridophytes do have conductive vessels and can distribute nutritive substances throughout their structure. In the next evolutionary link are the higher plants, which have conducting vessels and also with true organs (root, stem and leaves) and their form of reproduction is solely sexual and in this way they have become the predominant plants on Earth. .
Higher plants are divided into two large groups: gymnosperms (which are evergreen because they carry out photosynthesis throughout the year) and angiosperms are plants that have flower and fruit (the flower allows the pollination of insects and the fruit protects the seeds of these plants and serves at the same time as food for species of the Kingdom animalia).