How beautiful and amazing is the underwater world,so he is mysterious. Until now, scientists are discovering some completely new, unusual species of animals, exploring the incredible properties of plants, expanding the scope of their application.
The vegetable world of oceans, seas, rivers, lakes andThe marshes are not as diverse as terrestrial, but they are also unique and beautiful. We will try to understand what these amazing underwater plants are, what is the structure of algae and their significance in the life of man and other living beings.
By common standards, algae are consideredgroup of lower plants. They are part of the Empire Cellular kingdoms. Plants and sub-kingdoms. Lower plants. In fact, such a division is based precisely on the features of the structure of the representatives' data.
They got their name for being able togrow and live under water. The Latin name is Algae. Hence the name of the science that deals with the detailed study of these organisms, their economic significance and structure, is formed - algology.
Modern data allow to attribute all available information about different types of representatives to ten departments. The basis of the separation is the structure and life activity of algae.
This classification does not reflect the structurealgae, but only shows their ability to photosynthesize at different depths, showing the pigmentation of a particular color. That is, the coloring of the plant is the sign by which it is attributed to this or that department.
Their main distinguishing feature is that the bodynot differentiated into parts. That is, algae do not, as in higher plants, have a clear division into a shoot consisting of a stem, leaves and a flower, and a root system. The structure of the body of algae is represented by a thallus, or thallus.
In addition, the root system is also absent.Instead of it there are special translucent thin thread-like processes, called rhizoids. They perform the function of attaching to the substrate, acting as if they were suckers.
Thallum itself can be of a very diverse form andcoloring. Sometimes some representatives strongly resemble the escape of higher plants. Thus, the structure of algae is very specific for each department, so in the future it will be considered in more detail on the examples of the corresponding representatives.
Thallus is the main distinguishing feature of any multicellular algae. Features of the structure of this organ consist in the fact that thallus can be of different types.
The first three are most characteristic for colonial and unicellular forms, the rest for more advanced, multicellular, complex in organization.
This classification is only approximate, since each type has transitional variants, and then it is almost impossible to distinguish one from another. The facet of differentiation is erased.
The peculiarity of these plants is originallyin the structure of their cells. It is somewhat different from that of higher representatives. It is possible to identify several main points by which cells are excreted.
In other respects, the structure of the algal cell obeys the general rules of this in higher plants. They also have:
In this case, the cellular structure of unicellular algae corresponds to that of prokaryotic creatures. That is, there are also no nucleus, chloroplasts, mitochondria and some other structures.
The cellular structure of multicellular algae fully corresponds to that of higher terrestrial plants, with the exception of certain species features.
This department includes the following types:
In total, there are more than thirteen thousand species. Main classes:
The features of the structure of unicellular organisms areThe fact that outside the cage is often covered by an additional shell, performing the function of a peculiar skeleton, is a pellicle. This allows it to be protected from external influences, to keep a certain shape, and also over time to form on the surface beautiful and amazing patterns of metal ions and salts.
As a rule, in the structure of green algaeUnicellular type necessarily includes some organoid of movement, most often a flagella at the posterior end of the body. A spare nutrient is starch, butter or flour. The main representatives: chlorella, chlamydomonada, volvox, chlorococcus, protocaccus.
Very interesting are representatives of siphon,as kaulerpa, codum, acetobularia. Their thallus is not a filamentary or lamellar type, but one giant cell that performs all the basic functions of vital activity.
Multicellular may have a lamellar structureor filamentous. If we are talking about lamellar forms, then often they are multilayered, not just single-layered. Often, the structure of algae of this type is very similar to shoots of higher terrestrial plants. The more branched the tall, the more similar.
The main representatives are the following classes:
Colonial forms are special.The structure of green algae of this type consists in a close interaction between a large cluster of unicellular representatives, combined, as a rule, with mucus in the external environment. The main representatives can be considered volvoksov, protokokkovyh.
The main habitats are fresh water bodies andsea, oceans. Often cause the so-called flowering of water, covering all the surface of it. Chlorella is widely used in cattle breeding, as it purifies and enriches the water with oxygen, and the dry residue goes to feed cattle.
Unicellular green algae canIt is used in spacecraft for the production of oxygen as a result of photosynthesis without changing its structure and death. According to the time interval, this department is the oldest in the history of underwater plants.
Another name for the department is the Crimson.It appeared because of the special color of the representatives of this group of plants. It's pigments. The structure of red alga as a whole satisfies all the basic features of the structure of lower plants. They can also be unicellular and multicellular, they have a different type of thallus. There are both large and extremely small representatives.
However, their coloration is due to certain features - along with chlorophyll these algae have a number of other pigments:
They mask the main green pigment,so the color of plants can range from yellow to bright red and crimson. This is due to the absorption of virtually all wavelengths of visible light. The main representatives: anfeltia, phyllophora, gracilia, porphyry and others.
Capable of living in fresh water, howevermost are still marine representatives. The structure of red algae, and specifically the ability to produce a special substance agar-agar, makes it possible to widely use it in everyday life. Especially it concerns the food confectionery industry. Also, a significant proportion of individuals are used in medicine and are directly consumed by humans for food.
Often, within the framework of the school curriculumplants, their various departments, the teacher asks the students: "List the features of the structure of brown algae." The answer is this: thallus has the most complex structure of all the known individuals of lower plants, inside the thallus, which is often of impressive size, with conductive vessels; thall itself has a multi-layered structure, which is why it resembles the tissue type of the device of higher terrestrial plants.
The cells of representatives of these algae produce a special mucus, so the outside is always covered with a kind of layer. Spare nutrients are:
That's what you need to say, if you are asked: "List the features of the structure of brown algae." They are actually many, and they are unique against the background of other representatives of underwater plants.
Brown algae - the main source of organicconnections not only for marine herbivores, but also for people living in the coastal zone. Their consumption in food is widespread among different peoples of the world. Of them, medicines are made, flour and minerals, alginic acids are obtained.
