How the colonial form of life appeared briefly. Type Intestinal

Features of the formation of the colonial system

In a slave society, the word "colony" meant "settlement". Ancient Egypt, Mesopotamia, Greece, Rome had colonies-settlements on foreign territory. Colonies in modern meaning words appeared in the era of the Great geographical discoveries at the end of the 15th - beginning of the 16th centuries. As a result of the great geographical discoveries, begins to form colonial system. This stage in the development of colonialism is associated with the formation of capitalist relations. Since that time, the concepts of "capitalism" and "colonialism" have been inseparably linked. Capitalism is becoming the dominant socio-economic system, the colonies are the most important factor accelerating this process. Colonial plunder and colonial trade were important sources of initial capital accumulation.

A colony is a territory devoid of political and economic independence and dependent on the metropolises. Capitalist relations are implanted in the conquered territories of the metropolis. This happened in the colonies of England in North America, Australia, New Zealand and South Africa... The local population could not resist the power of the colonialists, it was either destroyed or driven into the reservations. The main population in the states formed after independence was immigrants from Europe.

In the East, the colonialists were unable to establish themselves absolutely. In these countries, they were a minority, and attempts to change the existing structure of society as a whole ended in failure. The main reason can be considered the centuries-old traditions and stability of the Eastern society. At the same time, it would be wrong to say that the colonialists did not influence the course historical development peoples of Asia and Africa. In this regard, it is important to note that in these regions the introduction of capitalist relations met with opposition from traditional structures.

Thus, it is important to highlight the main stages and nature of colonization, which changed with the development of European capitalism, and to identify the nature of the changes taking place in the countries of the East during the period of colonialism.

Initial period

The period of the initial accumulation of capital and manufacturing production predetermined the content and forms of relations between colonies and metropolises. For Spain and Portugal, colonies were primarily sources of gold and silver. Their natural practice was frank robbery up to the extermination of the indigenous population of the colonies. However, the gold and silver exported from the colonies did not accelerate the formation of capitalist production in these countries.

Most of the wealth plundered by the Spanish and Portuguese contributed to the development of capitalism in Holland and England. The Dutch and British bourgeoisie profited from the supply of goods to Spain, Portugal and their colonies. The colonies seized by Portugal and Spain in Asia, Africa and America became the object of the colonial conquests of Holland and England.

The period of industrial capitalism

The next stage in the development of the colonial system is associated with the industrial revolution, which begins in the last third of the 18th century. and ends in developed European countries by about the middle of the 19th century.

The period is coming exchange of goods, which draws the colonial countries into world commodity circulation. This leads to double consequences: on the one hand, the colonial countries are turning into agrarian and raw materials appendages of the metropolises, on the other hand, the metropolises contribute to the socio-economic development of the colonies (the development of local industries for the processing of raw materials, transport, communications, telegraph, printing, etc. ).

By the beginning of the First World War, at the stage of monopoly capitalism, the colonial possessions of three European powers were formed:

At this stage, the territorial division of the world is completed. The leading colonial powers of the world are stepping up the export of capital to the colonies.

Colonial flagellates (Volvox, Pandorina, Eudorina, etc.) are considered as transitional forms from unicellular to multicellular organisms. The most simply arranged colonies consist of 4-16 completely identical unicellular individuals - zooids, connected together. Each zooid has a flagellum, ocellus, chromatophores, and a contractile vacuole.

The representative of the colonial species of flagellates - Volvox globator forms large spherical colonies, consisting of many thousands of vegetative zooids - small pear-shaped cells, each of which has two flagella. The diameter of the ball is 1-2 mm. Its cavity is filled with a gelatinous substance. All volvox cells (zooids) are interconnected by thin protoplasmic bridges, which makes it possible to coordinate the movement of the flagella. The colony moves in the water due to the coordinated movement of the flagella of individual individuals.

In Volvox, the division of the colony cell function is already observed. So, at one pole of the colony, with which it moves forward, there are cells with more developed light-sensitive eyes, and in the lower part of the colony (where the eyes are poorly developed) there are cells capable of division (reproduction cells, generative zooids), i.e. differentiation into somatic and sexual individuals is noted.

Reproduction of volvox is carried out due to special - generative - zooids. They go from the surface to the interior of the colonies and here, multiplying by division, form daughter colonies. After the withering away of the maternal colony, the daughters begin independent life... In the fall, due to generative individuals, sexual forms are also formed: large immobile macrogametes (female sexual zooids) and small microgametes equipped with two bundles (male sexual zooids). In the process of gametogenesis, individuals that turn into macrogametes do not divide and increase in size. Individuals producing microgametes divide many times and form a large number of small two-flagellates. Microgametes actively seek out motionless macrogametes and merge with them, forming zygotes. Zygotes give rise to new colonies. The first two divisions of the zygote are meiotic. Consequently, in colonial flagellates, only the zygote has a diploid set of chromosomes, all other stages life cycle- haploid.

Colonial flagellates are of great biological interest in general biological terms. There is no doubt that the formation of colonies of the most ancient protozoa was a step on the way to the emergence of multicellular organisms. Some biologists (A.A.Zakhvatkin) believe that Volvox colonies, consisting of thousands of zooids, should be regarded as primitive multicellular animals.

Question 1. Explain why coelenterates received such a name. On what grounds can an animal be attributed to this type?

The body of the coelenterates is two-layer, that is, the cells that form it are located in two layers and form a cavity into which only one hole leads - the mouth. This cavity is called intestinal, hence the name - coelenterates. All animals belonging to this type have radial (radial) symmetry, which is characteristic, as a rule, of organisms leading an attached lifestyle. Another sign characteristic of coelenterates is the presence of stinging cells in the outer layer. The combination of these features indicates that the animal belongs to this type.

Question 2. Prove that coral, jellyfish and hydra belong to the same type of animal.

Coral (more precisely, coral polyp), jellyfish and hydra belong to the same type - Intestinal, since they have characteristics characteristic of this type. All of them are two-layer multicellular animals, have radial (radial) symmetry, have an intestinal cavity, as well as stinging cells in the outer layer of the body.

Question 3. What is the significance of coelenterates in nature?

First of all, coelenterates are part of the aquatic communities of organisms. They actively feed on other living organisms: protozoa, small crustaceans, fish fry, that is, they are predators. Other predatory animals hardly eat coelenterates, since the poison from stinging capsules burns them and can even lead to death.

Some polyps live on mobile animals. For example, an anemone polyp attaches to the shell of a hermit crab. Actinia protects the cancer with its stinging cells and eats the remains of its food. The movement of the crayfish contributes to the change of water around the sea anemone, and, consequently, to the improvement of gas exchange.

Some coral polyps form marine reefs and entire islands, around which favorable conditions for the life of other marine life are created.

Question 4. How did the colonial form of life come about?

The emergence of colonial life can be seen in the example of existing colonial polyps. In them, a mobile larva formed as a result of sexual reproduction, having made a certain way in the water column, attaches to the bottom and turns into a stationary stage - a polyp. Asexually, other polyps form on the body of the polyp, and then bud off, but do not separate, like in hydra, other polyps, which soon also begin to bud. This is how a colony is formed. The intestinal cavities of the polyps communicate, and food captured by one of the polyps is absorbed by all members of the colony.

It can be assumed that the colonial form of life arose due to the fact that the organisms formed as a result of reproduction of the original individual (s) did not move away from each other. Between them (due to the differences in the conditions in which the organisms were located in the center and on the periphery of the grouping), a division of functions arose. Some began to be responsible for attachment to the substrate, others for food, others for protection from enemies, others for reproduction, etc. This specialization led to the transformation of the group into a single whole - a colony.

Question 1. Explain why the coelenterates received such a name. By what signs can an animal be attributed to this type?

The body of the coelenterates is two-layer, that is, the cells that form it are located in two layers and form a cavity, into which only one opening leads - the mouth. This cavity is called intestinal, hence the name - coelenterates. All animals belonging to this type have radial (radial) symmetry, which is characteristic, as a rule, of organisms leading an attached lifestyle. Another sign characteristic of coelenterates is the presence of stinging cells in the outer layer. The combination of these characters indicates that the animal belongs to this type.

Question 2. Prove that coral, jellyfish and hydra belong to the same type of animal.

Coral (more precisely, coral polyp), me-duza and hydra belong to the same type - Intestinal, since they have characteristics characteristic of this type. All of them are two-layer multicellular animals, have radial (radial) symmetry, have an intestinal cavity, as well as streak cells in the outer layer of the body.

Question 3. What is the significance of coelenterates in nature?

First of all, coelenterates are part of the aquatic communities of organisms. They actively feed on other living organisms: protozoa, small crustaceans, fish fry, that is, they are predators. Other predatory animals hardly eat coelenterates, since the poison from stinging capsules burns them and can even lead to death.

Some polyps live on mobile animals. For example, an anemone polyp attaches to the shell of a hermit crab. Actinia protects the cancer with its stinging cells and eats the remains of its food. The movement of the crayfish, on the other hand, contributes to the change of water around the anemone, and, consequently, to the improvement of gas exchange.

Some coral polyps form sea reefs and entire islands, around which favorable conditions are created for the life of other marine life.

Question 4. How did the colonial form of life appear?Material from the site

The emergence of the colonial form of life can be seen on the example of existing colonial polyps. In them, the mobile larva formed as a result of sexual reproduction, having made some way in the water column, attaches to the bottom and turns into a stationary stage - a polyp. Asexually, on the body of the polyp, other polyps form and then bud off, but do not separate, like in the hydra, which soon also begin to bud. This is how a colony is formed. The intestinal cavities of the polyps communicate, and the food captured by one of the polyps is assimilated by all members of the colony.

It can be assumed that the colonial form of life arose due to the fact that the organisms formed as a result of the reproduction of the original individual (s) did not move away from each other. Between them (due to the differences in the conditions in which the organisms were located in the center and on the periphery of the group), a division of functions arose. Some began to be responsible for attachment to the substrate, others for food, others for protection from enemies, others for reproduction, etc. This specialization led to the transformation of the group into a single whole - a colony.