Plants are the most beautiful part of the biomass of our planet. Without them, the existence of neither animals, nor mushrooms, nor humans would have been possible. They are very different, have an extraordinary variety of species and simply amaze with their grandeur and splendor. However, not always the plants had the same appearance. Having gone through a complex process of evolutionary transformations, only the most persistent, genetically favored ones were able to adapt and survive. The main ones that dominate in numbers are two groups. We will consider them below.
General characteristics of the plant kingdom
Organisms, which correspond to several characteristics, are usually classified as plants:
- unlimited growth throughout life;
- the implementation of the photosynthesis process (autotrophic method of generating energy);
- motionless lifestyle;
- ability to emit oxygen.
Today, there are about 350 thousand different representatives of this kingdom. They strike with a variety of life forms and adaptations to the conditions of existence. All of them are usually divided into certain groups and taxa.
Classification
The Kingdom of Plants is divided into two large sub kingdoms: Higher and Lower. Each of them includes several more different taxonomic units:
- Lower plants are represented by algae, which are divided into classes. Their main difference is the lack of a body differentiated into organs.
- Higher plants are represented by the following departments: ferns, mosses, horsetails, crowns, gymnosperms, angiosperms.
Naturally, each of the listed taxa has even smaller units within itself: classes, orders, families, genera, and species. The most numerous and adapted of all - angiosperms, or flowering. However, this was not always the case. Once upon a time on the planet spore dominated, then gymnosperms.
There are signs of gymnosperms and angiosperms that allow us to distinguish them from the rest and understand what caused them to prevail over all others. Consider them in more detail below.
Common signs of gymnosperms
This department is very interesting and extremely important for the life of the whole planet. Gymnosperms are represented by several main classes:
- Ferns are seed.
- Cycas.
- Conifers.
- Bennetite
- Ginkgo.
- Oppressive.
In total there are about 800 different species. A common feature of gymnosperms and angiosperms is an obvious feature reflected in the name: the presence of a seed in which the embryo develops. However, this same symptom can be called a difference, because the seed is located in different ways.
A common sign of gymnosperms (all without exception) can be called the development of the seed on the open scale of the cone. Thus, it is like naked, which served as the reason for the name of the department.
You can also identify several more features that representatives of gymnosperms possess:
- Among them, only trees and shrubs are found, grassy forms are completely absent.
- In most, the leaves are transformed into thin needles, covered with a dense cuticle.
- The conducting system is represented by albuminoid cells and sieve tubes , vessels are absent.
- Sperm are motionless, carried by the wind.
- Dioecious plants (dioecious).
- The process of fertilization and seed development takes about two years.
- The endosperm of the embryo is haploid by the set of chromosomes, since fertilization is simple.
Conifers have reached a special variety among gymnosperms. They constitute the bulk of the trees in many forests of our planet. Examples of these plants are:
- larch;
- fir;
- spruce;
- Pine;
- cedar;
- thuja and others.
Signs of flowering plants
The fact that the common sign of gymnosperms and angiosperms is the presence of a seed has become one of the reasons why flowering plants have become more widespread. After all, their seed is reliably protected by the pericarp and the pulp of the fetus, which makes it invulnerable to weather conditions.
In addition to this trait, there are several other significant and important characteristics of angiosperms:
- There is a clearly constructed conductive system consisting of vessels.
- Life forms are represented by all types; a variety of trees, shrubs and grasses allows you to settle in any place.
- Fertilization is double, which allows the formation of a triploid endosperm. The process is fast.
- Pollination is possible not only by the wind, but also by insects, animals, self-pollination, and other methods.
- The main generative organ that gives a huge advantage is the flower.
Being the youngest group in evolutionary terms, the flower ones managed to become both the most progressive and numerous. Their number is close to 250 thousand species. All this became possible precisely due to the acquisition and consolidation of genetically described traits.
Signs of similarity between gymnosperms and angiosperms
Also a common feature of gymnosperms and angiosperms is the fact that they do not need water for reproduction. This distinguishes them from spore ones, which are very dependent on moisture.
In addition, it can be noted that a common feature of gymnosperms and angiosperms is the good development of autonomic organs. The stem, leaves and root are essential in the life of the body. Both in the first and in the second group, these signs are manifested very well and distinctly.
Another similarity is the formation of large forests, the settlement of vast territories and the dominance of other plants in the world. The obvious and undeniable advantage of both departments is the reproduction with seeds. After all, if there is a seed, then the embryo has significant reserves for nutrition for the first time before germination. Disputed have no such advantage, therefore their chances of survival are sharply reduced.
A common feature of gymnosperms and angiosperms is the ability to form fruits. In the former, these are cones with seeds, in the latter, they are different, both juicy and dry. This makes seed distribution possible with birds.
Differences between gymnosperms and flowery
In addition to similarities, there are differences between the main departments of the plant kingdom. These are such signs of gymnosperms and angiosperms that make it possible to distinguish them from each other and explain the numerical superiority of some over others.
Several main points can be identified:
- Time spent on fertilization and reproduction, the formation of a new organism.
- The position of the seed on the plant (open or protected).
- The presence or absence of certain life forms.
- Pollination method.
- Importance in the evolution of animals.
- The biological role in nature and importance to humans.
Phylogenetic features of gymnosperms
If we talk about the origin of gymnosperms, then we should turn to the Devonian period, that is, look back about 370 million years ago. It was then that they managed to supplant ferns, mosses, horsetails and crowns, which had been a priority for many millions of years.
The main reason for this is independence from water in the process of reproduction and seed formation. Today, many of the ancient forms of gymnosperms became extinct, forming an active supply of coal. However, a variety of new forms appeared. In addition, some species of pines and ginkgo are still known, whose age is estimated at millennia.
At one time gymnosperms did not manage to create normal fodder supply for existing animals and birds. This was one of the reasons why the flowering opportunists evolved and became more widespread.
Angiosperm Phylogenesis
A relatively young group of plants, the appearance of which is attributed to the end of the Jurassic period. The progressive traits that we already mentioned above allowed the representatives of this department to settle in all climatic zones and take a dominant position.
It is important that with the emergence and resettlement of angiosperms, feed for both animals and birds began to be grabbed. Yes, and man today cannot imagine his life without the products these plants give us. After all, all cereals, vegetables, berries and others are flowering. Therefore, we owe them life.
Importance and biological role of plants
If we talk about the importance of both departments, the common sign of gymnosperms and angiosperms is the ability to carry out the process of photosynthesis and produce a huge amount of oxygen for breathing to all living things. Both coniferous and flowering plants occupy colossal land areas. With their tireless work, they produce not only oxygen, but also absorb carbon dioxide, saving people from the greenhouse effect. They are producers of organic matter. Thanks to plants, all other creatures live on the planet, so it is difficult to overestimate their role in nature.