plants - a beautiful part of the biomass of the planet.Without them it would be impossible for the existence of any animals or fungi or human.They are very different, are of high species diversity and just hit its grandeur and magnificence.However, not all plants have the same look.Having a complex process of evolutionary transformation, we managed to adapt and survive only the most resistant genetically advantageous dispensation.Chief among them, who dominated in number, are the two groups.It is their we discuss below.
General characteristics of the plant kingdom
The plants are usually attributed organisms that correspond to several factors:
- unlimited growth throughout life;
- implementation of the process of photosynthesis (autotrophic way to generate energy);
- fixed way of life;
- ability to release oxygen.
Today there are about 350 thousand representatives of the various kingdoms.They affect the diversity of life forms and adapted to the conditions of existence.All of them are divided into certain groups and taxa.
Classification
plant kingdom is divided into two large subkingdoms: higher and lower.Each of them includes several different taxonomic units:
- Lower plants presented algae, which are divided into classes.Their main difference - the lack of a body, differentiated organs.
- higher plants represented by the following departments: ferns, mosses, horsetails, club mosses, gymnosperms, angiosperms.
Naturally, each of these taxa is still smaller units within itself: classes, orders, families, genera and species.The most numerous and adapted from the all - angiosperms, or flowering.However, it was not always.Once the planet was dominated by spore, then - gymnosperms.
There are signs of gymnosperms and angiosperms, which allow to distinguish them from others, and to understand that the reason for the predominance over the other.Let us consider them in more detail below.
Common symptoms gymnosperms
This department is very interesting and very important for the life of the entire planet.Gymnosperms are represented by several major classes:
- Ferns seed.
- Sagovnikovye.
- Conifer.
- Bennetitovye
- Ginkgoaceae.
- Gnetova.
total there are about 800 different species.A common feature of gymnosperms and angiosperms is obvious, reflected in the title of a feature: the presence of semen, which is developing fetus.However, the same can be called a sign of distinction, because the seed is different.
common feature of gymnosperms (without exception) can be called the development an open flake seed cones.Thus, it is like a naked, that was the reason for the name of the department.
You can also define a few features that have representatives gymnosperms:
- Among them there are only trees and shrubs, herbaceous forms are completely absent.
- Most leaves are converted into thin needles, covered with thick cuticle.
- conducting system is represented albuminoid cells and sieve tubes, the vessels are not available.
- spermatozoa motionless, carried by the wind.
- Plants dioecious (dioecious).
- process of fertilization and seed development takes about two years.
- endosperm embryo haploid sets of chromosomes for as fertilization is simple.
Particular diversity among gymnosperms conifers reached.They make up the bulk of the tree in many forests of our planet.Examples of these plants can serve:
- larch;
- fir;
- spruce;
- pine;
- cedar;
- Thuja and others.
signs of flowering plants
What common feature of gymnosperms and angiosperms is the presence of semen, has become one of the reasons why the flowering became widespread.After all, they have reliably protected the seed pericarp and pulp of the fruit, making it impervious to the weather.
addition to this feature, and there is still some significant and important characteristics of angiosperms:
- There is clearly built conduction system, consisting of vessels.
- Life forms are represented all types;the variety of trees, shrubs and herbs makes it possible to settle in any place.
- double fertilization, which allows to form triploid endosperm.The process is fast.
- Pollination is possible not only wind, but also insects, animals, and other methods of self-pollination.
- main generative organs, giving a huge advantage - flower.
Being the youngest group in evolutionary terms, flowering and managed to become the most progressive and numerous.Their number is nearing 250 thousand species.All this became possible due to the acquisition and development of genetically-described characteristics.
Symptoms similarities gymnosperms and angiosperms
also a common feature of gymnosperms and angiosperms is the fact that breeding they do not need water.This distinguishes them from the spore, which are very dependent on moisture.
In addition, it should be noted that the common feature of gymnosperms and angiosperms is a good development of the vegetative organs.The stalk, the leaves and the root are important in the life of an organism.As in the first and the second group of these symptoms appear very well and clearly.
Another similarity - the formation of large forest areas, the population of vast territories in the world and dominion over other plants.The obvious and indisputable advantage of both departments - propagation using seeds.After all, if there is a seed, then the fetus has significant reserves of power for the first time before germination.Spore such benefits are not, so their chances of survival decrease dramatically.
common feature of gymnosperms and angiosperms is the ability to generate results.At first it cones with seeds, the second - as different as juicy and dry.This makes it possible to seed dispersal using birds.
differences between gymnosperms and flowering
In addition, there are similarities and differences between the major departments of the plant kingdom.These are signs of gymnosperms and angiosperms, that distinguish them from each other and explain the numerical superiority of one over the other.
can define a few basic points:
- The time for fertilization and reproduction, the formation of a new organism.
- Situation seed per plant (open or secure).
- presence or absence of various life forms.
- method of pollination.
- value in the evolution of animals.
- biological role in nature and value to humans.
Phylogenetic especially gymnosperms
If we talk about the origin of gymnosperms, you should refer to the Devonian period, that is, to look about 370 million years ago.It was then that they were able to oust the ferns, mosses, horsetails and club mosses, which were a priority for many millions of years.
main reason for this - no water during the breeding and seed formation.Today, many of the ancient forms of extinct gymnosperms, forming the active reserve of coal.However, there was also a variety of new forms.In addition, still known to some types of pines, ginkgo, age thousands of years.
At the time, gymnosperms failed to create for the existing animals and birds to ensure normal feeding.This was one of the reasons that have evolved and got more common opportunists-flowered.
Phylogeny angiosperms
relatively young group of plants, the appearance of which dates from the end of the Jurassic period.Advanced features that we mentioned above, allowed the representatives of the department to settle in all climatic zones and to dominate.
It is important that with the emergence and dispersal of angiosperms was enough food as the animals and birds.Even today, people can not live without foods that provide us with these plants.After all, cereals, vegetables, berries and others - it is flowering.Therefore, to them we owe our lives.
value and biological role of plants
If we talk about the importance of both departments, the common feature of gymnosperms and angiosperms - the ability to perform photosynthesis and produce huge amounts of oxygen for respiration of all living beings.And conifers, and flowering occupy huge area of land.His tireless work they produce not only oxygen, but also absorb carbon dioxide, rescuing people from the greenhouse effect.They are the producers of organic matter.Through live plants all other beings on the planet, so to overestimate their role in nature is difficult.
