The first terrestrial plants were ... The first plants on Earth

We, contemporaries, know very little about the first representatives of the plant world. Unfortunately, there are few fossil remains. However, scientists, using fossilized prints left by ancient plants, still restored their appearance, and also examined the features of the structure of plants that became the first inhabitants of the land.

Science, which studies the features of the structure and life activity of fossil plants, is called "paleobotany." It is paleobotanists who are engaged in the search for answers to the questions of the origin of the plant world.

Classification of spore plants

The first plants on Earth multiplied by spores. Among the modern representatives of the flora there are also spore plants. According to the classification, all of them are united in one group - "higher spore plants". They are represented by the Rhinophytes, Zosterophylophytes, Trimsyphophytes, Psilotophytes, Bryophytes (Bryophytes), Lycopodiophytes (Plauniform), Ekvizetofitami (Khvoschevidnye) and Polypodifitami (Pteridophytes). Among these departments, the first three are completely extinct, and in the composition of others there are both extinct and now existing groups.

Rinophytes are the first sushi plants

The first land plants were representatives of the flora, who mastered the Earth about 450 million years ago. They grew near various water bodies or in places of shallow water, for which periodic podaplivanie and drying was typical.

All plants that have mastered the land have a common feature. This division of the body into two parts - aboveground and underground. Such a structure was characteristic of the Rionophytes.

Remains of ancient plants were first discovered in the second half of the XIX century in the territory of modern Canada. But for unexplained reasons, this finding was not of interest to botanists. And in 1912, near the Scottish village of Raini, a local rural doctor found several more fossilized plants. He did not know that he was holding the remnants of the first land inhabitants, but, being very inquisitive, he decided to thoroughly study an interesting find. After making a cut, he found well-preserved remains of plants. The stem was very thin, bare, and attached to it were oblong-shaped processes (similar to elongated balls) with very thick walls. Information about the find quickly reached the paleobotanists, who found out that the remnants were the first terrestrial plants. There were doubts about the names of these ancient remains. But as a result we decided to go for the simplest go and called the extinct plants the Rionophytes by the name of the village near which they were found.

Features of the structure

The external structure of the Riniophytes is very primitive. The body forked in a dichotomous type, that is, in two parts. Leaves and real roots, they did not yet have. Attaching to the soil was carried out with the help of rhizoids. As for the internal structure, on the contrary, it was quite complex, especially compared to algae. Thus, the cover cloth had a stomatal apparatus, through which the processes of gas exchange and evaporation of water were carried out. Due to their lack of mechanical tissues, the first plants on Earth were relatively small in height (not more than 50 cm) and stem diameter (about 0.5 cm).

Paleobotany believe that all modern terrestrial plants originated from the Rionophytes.

Psilophytes - the first terrestrial plants. Is this true?

More likely no than yes. The name "psilophytes" really figured back in 1859. This American paleobotanist Dawson called so one of the found plants. He chose this option, because in translation this word means "bare plant". Up to the beginning of the XX century the Psilophytes called the genus of the most ancient plants. But according to the results of subsequent audits, this genus has ceased to exist, and the application of this name has become incompetent. At the moment, the most fully described genus Rinia gives the name to the entire department of the most ancient representatives of terrestrial flora. Consequently, the first terrestrial plants were the Rhinophytes.

Typical representatives of the first terrestrial plants

Presumably, the first terrestrial plants were cousonia and rinia.

One of the most ancient representatives of the flora was Kuksonia, which had the appearance of a small bush with a height of no more than 7 cm. A favorable growth medium for it was marshlands. The fossilized remnants of couson and related species are found in the Czech Republic, the United States of America and in some areas of Western Siberia.

Close by kinship, rhinia is much better studied than kuksonia. Her body was more massive: in height the plant could reach 50 cm, and the diameter of the stem - 5 mm. At the end of the stem of the Rhine was a dome, in which there were spores.

Ancient representatives of the genus Rinia gave rise to many plants of the tropics and subtropics. According to modern classification, they are united in the department of Psilophytes. It is very small, because it includes about 20 species. By some indications, they are very similar to their ancient ancestors. In particular, both have dichotomous branching. The approximate growth of Psilophytes is from 25 to 40 cm.

Modern finds

Until recently, paleontologists found in sediments older than 425 million years only remnants of primitive tri-state spores with a smooth shell. Such findings were found in Turkey. They are referred to the Upper Ordovician. The found specimens could not shed light on the information on the time of the formation of vascular plants, since they were single and for them it was completely unclear what exactly representatives of the plant species belonged to smooth disputes.

But not so long ago in Saudi Arabia, there were found authentic remains of trilogy spores with an ornamented shell. It was determined that the age of the samples found varies from 444 to 450 million years.

Flowering of vascular plants after glaciation

In the second half of the Ordovician, the present Saudi Arabia and Turkey were the northern part of the supercontinent of Gondwana. This, apparently, was the original habitat of vascular plants. For a long historical period, they lived only in their "evolutionary cradle", whereas the planet was inhabited by representatives of primitive mosses with their cryptospores. Most likely, the mass dispersal of vascular plants began after the great glaciation that occurred at the turn of Ordovician and Silurian.

Body theory

In the course of the study of the Rneophytes, the so-called telomial theory was created, which was created by the German botanist Zimmermann. It revealed the peculiarities of the structure of the Riniophytes, which by that time had been recognized as the first terrestrial plants. Zimmermann also showed the proposed ways of becoming important vegetative and reproductive organs of higher plants.

According to the German scientist, the body of the Rinophytes consisted of radially symmetric axes, the end branches of which Zimmerman called telomes (from the Greek telos - "end").

Evolutionary way, the telomes, having undergone numerous changes, became the main organs of higher plants: stems, leaves, roots, sporophylls.

So, now you can unequivocally answer the question "What was the name of the first terrestrial plants?". Today the answer is obvious. These were the Rneophytes. They were the first to reach the surface of the Earth and became the progenitors of the representatives of the modern flora, despite the fact that their external and internal structure was primitive.