Algae - types and names, meaning
Algae are isolated in a separate sub-kingdom. And this is not surprising! Scientists have proven that despite the absence of a stem and root, as in higher plants, these unique living organisms are not included in their kingdom, since they have many features that characterize them as a separate area of \u200b\u200bliving organisms.
Biology - a science that studies all life on the planet, gives its definition to this kingdom. Algae, in Latin "algae", are the lowest plant organisms. These are spore plant structures. Systematics defines more than 10 different species. Their names are written both in Latin and in Russian.
In nature, both unicellular and multicellular representatives of this kingdom are found. Below we will briefly consider the accepted classification of organisms, give examples, and also talk about the main processes of life of these living organisms.
In the end, let's try to figure out: what is their main role in nature, what are the main groups distinguished in this sub-kingdom, what are the characteristics of representatives of various departments, how algae look and how they live, and how they can be used in everyday life.
Department: Green Algae
The body of all algae is a thallus.
Chlamydomonas
List of representatives:
- chlamydomonas - a subspecies of unicellular mobile organisms;
- spirogyra - a subspecies of filamentous organisms;
- ulva - a subspecies of thallus-shaped marine deep-sea representatives;
- ulothrix is a subspecies of diatoms.
Using the example of Chlamydomonas, we will analyze: what green algae consist of, how the processes of respiration, nutrition and reproduction occur, etc.
It, as in a unicellular eukaryotic organism, includes:
- golgi apparatus;
- mitochondria;
- ribosomes;
- vacuoles.
In addition, she has an education, with the help of which carbon dioxide is retained in her body. It is through him that she breathes. Moves, as a rule, with the help of 2 flagella, like a "corkscrew". Reproduction in this species is of two types: asexual (spores) and sexual (heterolytic organisms).
The listed signs show that Chlamydomonas is the simplest creature.
Department: Red algae
In their structure, they are very similar to green algae.
These are the same unicellular algae, as a rule, having a dissected body: parts carry out photosynthesis, but nutrition occurs with a complete thallus. Reproduction is also of 2 types.
Department: Brown Algae
Representatives of this department are well adapted to harsh environmental changes. An example is kelp.
This is a multicellular organism covered with a membrane with pigments.
The thallus is divided into sole and plate. They do not have a conducting system - they absorb nutrients throughout the surface of the body. Reproduction is sexual, with each representative having reproductive organs of both sexes.
How do they eat
Nutrition occurs through photosynthesis, when carbon dioxide and other salts are exchanged with the help of chloroplasts in plastids.
In some cases, organic oxidation of oxygen is possible. Most often it is mixed: photosynthesis and heterotrophic nutrition occur simultaneously.
reproduction
There are two types: asexual and sexual.
Asexual can occur:
- Vegetatively - the formation of new forms and their subsequent separation from algae.
- Fragmentation - occurs in filamentous representatives: the thread is divided into two identical parts in a strictly defined position.
- Binary fission - unicellular are divided in half, and after that they exist independently of each other.
- Zoospores and aplanospores - organisms reproduce using flagella.
Sexual reproduction occurs due to the fusion of gametes of both sexes.
Variety of colors
It is explained by the different depths at which algae live. For example, red algae living at a depth of 200 meters have special pigments - carotenoids and phycobilins, capable of capturing light even at such a distance.
Green representatives live on the surface, and contain chlorophyll. Browns contain fucoxanthin, they absorb blue light, which is why they have such a shade.
Its useful to note: the deeper the place where algae grow, the less sunlight enters, and therefore the color is different.
Adaptation to land life
According to scientists, algae have adapted to terrestrial life, and the evolution went from green - representatives of unicellular organisms.
Further, the diversity of forms through the division of functions of individual elements of the structure of the body of algae, separation and fragmentation, adaptation to more difficult environmental conditions helped to create multicellular representatives of this kingdom.
Difference from higher plants
They lack a stem and roots, but have a thallus. In algae, there are no tissues like in higher plants. The organs of the reproductive system are usually unicellular.
Meaning
Algae play an important role in the life of animals and humans:
Despite such a wide range of useful properties, algae significantly harm water bodies and interfere with the full operation of the engines of ships, motor ships and steamers.
