The first living organisms arose at the time of the dominance of water on Earth. These living organisms living in an aquatic environment gave rise to the first unicellular flagellated algae (lower plants). It is assumed that multicellular algae arose from colonial forms of unicellular algae. There was a transition from a unicellular organism to a multicellular one. Multicellular algae have the simplest structure, the body is formed by one type of cell, there are no tissues or organs, they are attached to the substrate using rhizoids.
With change. environmental conditions (major mountain-building processes took place, land appears), plant organisms change. From multicellular algae under conditions of periodic flooding of coastal zones with water, the first land inhabitants arose - psilophytes(extinct representatives of lower spore plants0 and the first mosses (a blind thread in evolution). From one type of multicellular algae, psilophytes developed, the thallus of which consisted of several tissues: integumentary, mechanical, conductive, and from another type of multicellular algae, mosses developed, these are terrestrial plants, having organs - shoots and leaves, but not having roots.There is a transition from the cellular level to the single-tissue level, as well as to the organismal level.
Psilophytes and the first mosses reproduced by spores. Modern mosses also reproduce by spores. From the spore a pre-grown algae-like growth grows. Fertilization occurs only in the presence of water. The similarity of moss precursors to algae indicates the origin of mosses from algae.
From psilophytes arose ferns, horsetails and mosses.
They had a more complex structure than modern representatives. During the heyday of ferns on Earth, there was a humid and warm climate, frequent rains, and large nebula, all of which contributed to the intensive development of ferns. They were represented by giant trees up to 40 meters high.
They reproduced with the help of spores, and more advanced ones with the help of seeds. Fertilization occurred in the presence of water.
Modern ferns, horsetails and club mosses, are much smaller in size than their ancestors, and are herbaceous plants. But they have retained features of similarity with their ancestors; they reproduce by spores, spores germinate only with a sufficient amount of moisture. Thrusts developing from spores are similar to the thallus of multicellular algae and, like algae, they are attached to the soil with the help of rhizoids. Fertilization occurs only in the presence of water. Almost all ferns and horsetails are moisture-loving plants.
With the onset of the glacier, the climate changed, it becomes DRY and cold. Under the influence of environmental conditions, changes occurred in the plant world. Spore-bearing ferns decreased in size, and the first gymnosperms arose from ferns that reproduced by seeds. These plants had organs (stems, leaves, roots) with a more complex internal structure, they developed integumentary tissues, the cells of which have thick walls, and the conductive system (vessels and sieve tubes forming conductive bundles) was also improved. Gymnosperms reproduce by seeds, consisting of a plant embryo and a supply of nutrients.
Angiosperms evolved from ancient gymnosperms. They have a more complex body structure; angiosperms develop a modified shoot - a flower. The genital organs develop in the flower: stamens and pistil (the pistil is the female reproductive organ, the stamen is the male reproductive organ). The fertilization process will occur only after the pollination process (the transfer of pollen from the stamen to the stigma). Fertilization in flowering plants is double, after which a fruit with seeds inside develops from the ovary of the pistil of the flower. Thus, the seeds are protected from unfavorable conditions. Angiosperms reproduce and spread by seeds. Due to the more complex structure and protection of seeds, angiosperms gradually occupied a dominant position on Earth.
Consequently, changes in the level of plant organization in the process of evolution went in the direction of increasing complexity of organization. At first, the organism is represented by one cell, then numerous organisms arise, then differentiation into tissues and organs occurs. Further, the structure of the organs becomes more complex, which leads to the complication of the entire organism. The causes of these changes are environmental factors, hereditary variation and natural selection.
The Angiosperms department is divided into two classes:
Class Monocots; Class Dicotyledons.
Classes, in turn, are divided into families. Each family is characterized by certain characteristics by which plants are combined into a specific systematic group (genus, species - the smallest unit of classification). Systematic position of the May lily of the valley:
Department Angiosperms, class - Monocots, family - Liliaceae, genus - Lily of the valley, species - May lily of the valley.
Using knowledge about immunity, explain the purpose for which a person is vaccinated and given serums. How can you increase the body's protective properties? How to protect yourself from HIV infection and AIDS?
1. Skin, mucous membranes, fluids they secrete (saliva, tears, gastric juice, etc.)- the first barrier in protecting the body from microbes. Their functions: serve as a mechanical barrier, a protective barrier that prevents microbes from entering the body; produce substances with antimicrobial properties.
2. The role of phagocytes in protecting the body from microbes. Penetration of phagocytes - a special group of leukocytes - through the walls of capillaries to places of accumulation of microbes, poisons, foreign proteins that have entered the body, enveloping and digesting them.
3. Immunity. The production of antibodies by leukocytes, which are carried by blood throughout the body, combine with bacteria and make them defenseless against phagocytes. Contact of certain types of leukocytes with pathogenic bacteria, viruses, release of substances by leukocytes that cause their death. The presence of these protective substances in the blood ensures immunity the body's immunity to infectious diseases. The effect of different antibodies on microbes.
4. Prevention of infectious diseases. Introduction into the human body (usually in childhood) vaccines- weakened or killed pathogens of the most common infectious diseases - measles, whooping cough, diphtheria, polio, etc. - to prevent the disease. Human insusceptibility to these diseases
or the course of the disease in a mild form due to the production of antibodies in the body. When a person is infected with an infectious disease, administering blood serum obtained from recovered people or animals. Contents in serum antibodies against a particular disease.
5. Prevention of HIV infection and AIDS. HIV - human immunodeficiency virus; causing acquired immunodeficiency syndrome (AIDS). HIV infects and destroys a certain type of white blood cell, which ensures the formation of human immunity. AIDS patients are susceptible to various infections, which cause their death. HIV is usually transmitted through blood or semen. From an HIV-infected mother, the virus can infect the fetus through the placenta or enter the child's body through breast milk. Due to the lack of effective treatment, it is important to take precautions: avoid casual sex, use condoms during sexual intercourse, test donated blood for HIV antibodies, and use disposable syringes.
Algae are the original inhabitants of the seas, widespread in fresh waters. Higher plants are terrestrial plants that have mastered land, as well as fresh and brackish water bodies. Only very few representatives of higher plants have adapted to life in sea water.
The emergence of plants onto land was accompanied by the development of a system of adaptations to new living conditions, which significantly changed their appearance.
The possible appearance of the first land plants is judged by several finds that were of great importance for the study of the structural evolution of higher plants.
In 1859, J. Dawson discovered the fossilized remains of a plant in the Devonian deposits of Canada, which was called the “primordial goloros” - Psilophyton princeps. The plant was a system of forked axes covered with small spines (Fig. 11 B). Sporangia were located at the ends of arched, drooping branches. The unusual appearance of holoros did not allow it to be attributed to any of the plant taxa known at that time, and for a long time it remained a mystery of nature.
In 1912, rhinium was discovered in the Early Devonian sediments of Scotland ( Rhynia), differing from Holoros by the absence of any outgrowths on the axes and vertically oriented terminal sporangia (Fig. 11B). We have already mentioned the most ancient paleontological find - Cooksonia.
These and other similar ancient plants were previously combined into one taxon called psilophytes ( Psilophyta). However, the discovered plants most likely were representatives of groups that had already diverged quite far in the process of rapid evolution. This is not very significant. It is important that the study of the remains of all the oldest land plants found was of great importance for clarifying the initial model of the structure of higher plants and developing ideas about their morphological evolution.
It is no coincidence that at the end of the 19th and beginning of the 20th centuries attempts were made to create hypothetical models of the ancestors of higher plants. The greatest attention of researchers has attracted telome theory structure of ancient plants, in the development of which the main role belongs to V. Zimmerman (30-40s of the XX century).
According to the telome theory, the ancestors of higher plants had an axial organization. The presence of sporangia in Holorosa, Rhinia, Cooksonia and other plants that existed in the Silurian and Devonian proves that they were sporophytes, the main purpose of which was the formation of spores. For spores to disperse, the sporangia must be raised above the substrate. Consequently, the development of the sporophyte should have been accompanied by an increase in its size. This required the required amount of food products absorbed by the surface of the plant from the soil, which was clearly not enough, since its formation is associated with the decomposition of plant residues. The increase in surface area, which occurred as the sporophyte slowly grew, was achieved by its dismemberment, the simplest method of which was the forked branching of the axial organs. Their terminal branches were called teloms (from the Greek telos - end), and the parts connecting them were called mesomas (from the Greek mesos - middle). Telomas There were two types: fertile, with sporangia at the apex, and sterile, performing the function of photosynthesis.
The underground part of the plant was also forked. Numerous rhizoids developed on the surface of the terminal branches. These branches were later named rhizomoids(Takhtadzhyan, 1954). Thus, according to the telome theory, the main organs of the most ancient land plants were telomes, rhizomoids and mesomes connecting them (Fig. 12).
Rice. 12. Structure diagram
hypothetical
sporophyte of a higher plant.
Designations: mz - me-
zom, p - rhizoids,
rzm - rhizomoid, sp -
sporangium, s.t - sterile
body, f.t -
fertile body
The study of paleobotanical material, mainly fern-like ones, allowed G. Potonier (1912) to come to the conclusion that forked or dichotomous branching was the initial one for other types of branching (Fig. 13).
Rice. 13. Scheme of the evolution of branching of higher sporophytes
plants: A - equal dichotomy (isotomy); B - unequal
dichotomy (anisotomy); B - dichopodia; G - monopodium;
D - sympodium
At dichotomous branching the growth zone located at the top of each axis splits (bifurcates). Therefore, dichotomous branching is also called apical. The starting point for the evolution of this branching was an equal dichotomy - isotomy(Fig. 13 A), in which both branches grew at the same speed, and then their tips bifurcated again. If one of the branches was ahead of the other in development, an unequal dichotomy arose - anisotomy(Fig. 13 B). A sharp lag in the development of one of the branches led to dichopodial branching (Fig. 13 B), in which a zigzag-shaped main axis of the plant was formed.
From dichotomous branching, 2 types of lateral branches developed.
Straightening the main axis (first order axis) of the dichopodium and its acquisition of the ability for unlimited apical growth led to monopodial branching(Fig. 13 D). In this case, the lateral branches, or axes of the second order, were laid directly under the top of the main axis and were significantly inferior to it in development. On the axes of the second order, the rudiments of the axes of the third order were laid in the same way, etc.
In the most ancient plants, a second type of lateral branching has also been identified - sympodial(Fig. 13 D). In this case, the growth of the main axis stopped over time, and a lateral branch of the second order of branching, located near its top, straightened, shifted the end of the main axis to the side, and itself began to grow in the direction in which the main axis had previously grown. Then its growth also stopped, and its apex, which had been moved to the side, was replaced by a new lateral branch of the third branching order, etc. As a result, a straight or geniculate axis arose, which was a system of axes of different branching orders growing on one another.
Branching was not the only way to increase the surface of the sporophyte.
The bodies were cylindrical and had an oblique-vertical orientation. Only a small part of their surface was exposed to the sun's rays. An increase in the size of the light-perceiving surface was achieved by the formation of flattened organs - leaves, oriented more or less horizontally. The axial organs bearing leaves have turned into stems. This is how leafy plants arose. They differ greatly in appearance. Some of them, called microphyllic(from the Greek mikros - small and phyllon - leaf), have numerous small leaves, others called macrophyllic(from the Greek makros - large) are characterized by large leaves, often of a very complex structure.
According to the telome theory, the formation of leaves in the macrophyll line of plant evolution was determined by several interrelated processes (Fig. 14 B).
1. aggregation, or crowding, of telomes, occurring as a result of shortening and sometimes reduction of mesomes;
2. “reversal”, caused by the uneven development of sterile bodies, with one of them, with unlimited growth in length, becoming a stem, and the other body of the same dichotomy, greatly retarded in growth, shifted to the side and turned into a lateral organ;
3. fusion of telomes;
4. their flattening;
5. reduction of some telomes or their parts.
Rice. 14. Diagram illustrating
origin of enations (row A)
and typical leaves (row B)
All these processes were carried out simultaneously and were accompanied by a change in the planes of branching, which from comprehensive became bilateral, and then unilateral. The crowding of telomes, their branching in one plane, fusion at the edges and reduction up to the disappearance of the sporangia located on some telomes ultimately led to the formation of a lamellar organ - a leaf, which assumed the functions of photosynthesis. A classic example of leaves of this origin are the leaves of ferns, which have long apical growth.
The appearance of leaves greatly increased the surface of plants, which activated the processes of assimilation, gas exchange and transpiration (evaporation). Such plants could develop only in high humidity environments. During the process of evolution, the size of leaves decreased due to weakening of their growth, and they acquired adaptations that limited transpiration. All this expanded the adaptive capabilities of plants. Among modern plants, macrophyllia is characteristic not only of ferns, but also of seed plants.
The emergence of unicellular and multicellular algae, the emergence of photosynthesis: the emergence of plants on land (psilophytes, mosses, ferns, gymnosperms, angiosperms).
The development of the plant world took place in 2 stages and is associated with the appearance of lower and higher plants. According to the new taxonomy, algae are classified as lower (and previously included bacteria, fungi and lichens. Now they are separated into independent kingdoms), and mosses, pteridophytes, gymnosperms and angiosperms are classified as higher.
In the evolution of lower organisms, two periods are distinguished, which differ significantly in the organization of the cell. During period 1, organisms similar to bacteria and blue-green algae dominated. The cells of these life forms did not have typical organelles (mitochondiria, chloroplasts, Golgi apparatus, etc.). The cell nucleus was not limited by the nuclear membrane (this is a prokaryotic type of cellular organization). Period 2 was associated with the transition of lower plants (algae) to an autotrophic type of nutrition and with the formation of a cell with all the typical organelles (this is a eukaryotic type of cellular organization, which was preserved at subsequent stages of development of the plant and animal world). This period can be called the period of dominance of green algae, unicellular, colonial and multicellular. The simplest of multicellular organisms are filamentous algae (ulotrix), which do not have any branching in their body. Their body is a long chain consisting of individual cells. Other multicellular algae are dissected by a large number of outgrowths, so their body is branched (in Chara, in Fucus).
Multicellular algae, due to their autotrophic (photosynthetic) activity, developed in the direction of increasing their body surface for better absorption of nutrients from the aquatic environment and solar energy. Algae have a more progressive form of reproduction - sexual reproduction, in which a new generation begins with a diploid (2n) zygote, combining the heredity of 2 parental forms.
The 2nd evolutionary stage of plant development must be associated with their gradual transition from an aquatic to a terrestrial lifestyle. The primary terrestrial organisms turned out to be psilophytes, which were preserved as fossil remains in Silurian and Devonian deposits. The structure of these plants is more complex compared to algae: a) they had special organs of attachment to the substrate - rhizoids; b) stem-like organs with wood surrounded by phloem; c) rudiments of conducting tissues; d) epidermis with stomata.
Starting with psilophytes, it is necessary to trace 2 lines of evolution of higher plants, one of which is represented by bryophytes, and the second by ferns, gymnosperms and angiosperms.
The main thing that characterizes bryophytes is the predominance of the gametophyte over the sporophyte in their individual development cycle. A gametophyte is an entire green plant capable of self-feeding. The sporophyte is represented by a capsule (cuckoo flax) and is completely dependent on the gametophyte for its nutrition. The dominance of the moisture-loving gametophyte in mosses under the conditions of an air-terrestrial lifestyle turned out to be impractical, so mosses became a special branch of the evolution of higher plants and have not yet given rise to perfect groups of plants. This was also facilitated by the fact that the gametophyte, compared to the sporophyte, had poor heredity (haploid (1n) set of chromosomes). This line in the evolution of higher plants is called gametophytic.
The second line of evolution on the path from psilophytes to angiosperms is sporophytic, because in ferns, gymnosperms and angiosperms the sporophyte dominates in the cycle of individual plant development. It is a plant with a root, stem, leaves, sporulation organs (in ferns) or fruiting organs (in angiosperms). Sporophyte cells have a diploid set of chromosomes, because they develop from a diploid zygote. The gametophyte is greatly reduced and is adapted only for the formation of male and female germ cells. In flowering plants, the female gametophyte is represented by the embryo sac, which contains the egg. The male gametophyte is formed when pollen germinates. It consists of one vegetative and one generative cell. When pollen germinates, 2 sperm arise from the generative cell. These 2 male reproductive cells are involved in double fertilization in angiosperms. The fertilized egg gives rise to a new generation of the plant - the sporophyte. The progress of angiosperms is due to the improvement of the reproductive function.
Complication of plants in the process of evolution, classification of angiosperms. Determine the place of the May lily of the valley species in the system of the plant world (division, class, family, genus).
The complexity of plants in the process of evolution proceeded in the following directions:
· differentiation of cells, formation of tissues differing in structure and functions: educational, integumentary, mechanical, absorption, conductive, assimilation (carrying out photosynthesis);
· the emergence of specialized organs: shoots, including stems, leaves, generative organs, and roots;
· a decrease in the role of the gametophyte (haploid generation) in the life cycle and an increase in the role of the sporophyte (diploid generation);
· transition to propagation by seeds, which did not require the presence of water for fertilization;
· special adaptations in angiosperms to attract pollinating insects.
The department of angiosperms includes the classes dicotyledons and monocotyledons. The following systematic categories are studied in the school course: family, genus, species. Classification of lily of the valley:
Division angiosperms, or flowering plants
Class Monocots
Lily family
Genus lily of the valley
Type of lily of the valley
3. Using knowledge about immunity, explain the purpose for which a person is vaccinated and given serums. How can you increase the body's protective properties? How to protect yourself from HIV infection and AIDS?
Immunity is the body’s protective reaction to foreign bodies and substances. Immunity can be natural: congenital or acquired during life.
To develop resistance to the disease, artificial immunity is formed by introducing a weakened culture of microorganisms into a person. At the same time, antibodies are produced in the body. During subsequent infections, this allows the body to successfully fight the infection. This artificial immunity is called active. The first vaccination in history was smallpox vaccination.
If infection or penetration of poison (from a snake bite) has already occurred, the person is injected with a serum containing ready-made antibodies that help neutralize the adverse effects. Immunity resulting from the administration of serum is called passive.
The protective properties of the body increase with hardening, physical exercise, proper nutrition, and the content of sufficient vitamins in food. People with a balanced nervous system, enthusiastic, and optimistic people get sick less often.
AIDS (acquired immunodeficiency syndrome) is a disease that destroys the body's immune system as a result of infection with HIV (human immunodeficiency virus). HIV is transmitted through blood and sexual contact. In order not to get AIDS, you should categorically exclude drugs and casual sex from your life, and not abuse alcohol, which deprives a person of the ability to control his actions. Do not allow the use of shared syringes, needles, and in a hairdresser - a razor, manicure accessories that have not been disinfected (for this you need to soak for 25 minutes in alcohol or cologne).
1. Biosphere – global ecosystem, its boundaries. Living matter of the biosphere. The role of humans in the conservation of biodiversity.
The biosphere is the shell of the Earth inhabited by living organisms. Includes all ecosystems found on the planet. Life has been discovered in the deepest ocean depressions, in oil fields (anaerobic bacteria feeding on oil paraffins). The upper boundary of the biosphere is limited by high ultraviolet radiation in the upper layers of the atmosphere, the depth of habitat in the soil is limited by the high temperature of the underlying layers of the earth's crust.
The living matter of the biosphere has a colossal influence on all processes, participating in the processes of circulation of substances and energy. Suffice it to recall the formation of oxygen reserves in the atmosphere and the ozone screen, and limestone reserves in the oceans.
The stability of communities included in the biosphere depends on their species diversity. A decline in the abundance of one species does not have a serious impact on the community as a whole if the role of the eliminated species is “taken over” by existing existing species with similar needs. Therefore, the preservation of the entire diversity of species in ecosystems and the biosphere as a whole - biodiversity - is the main task of today in the field of nature conservation. Since significant harm caused by humans to the natural environment threatens the existence of many species as a result of direct extermination or destruction of habitats, coordinated, purposeful activities of all states are necessary to preserve biodiversity as a guarantee of the sustainable development of civilization and the conservation of nature.
The complexity of plants in the process of evolution proceeded in the following directions:differentiation of cells, formation of tissues differing in structure and functions: educational, integumentary, mechanical, absorption, conduction, assimilation (carrying out photosynthesis);
the emergence of specialized organs: shoots, including stems, leaves, generative organs, and roots;
a decrease in the role of the gametophyte (haploid generation) in the life cycle and an increase in the role of the sporophyte (diploid generation);
transition to propagation by seeds, which did not require the presence of water for fertilization;
special adaptations in angiosperms to attract pollinating insects.
The department of angiosperms includes the classes dicotyledons and monocotyledons. The following systematic categories are studied in the school course: family, genus, species. Classification of lily of the valley:
Division angiosperms, or flowering plants
Class Monocots
Lily family
Genus lily of the valley
Type of lily of the valley
-
Complication plants V process evolution, classification angiosperms. Define place kind lily of the valley May V system vegetable peace (Department, Class, family, genus). -
Complication plants V process evolution, classification angiosperms. Define place kind lily of the valley May V system vegetable peace (Department, Class, family, genus). -
Complication plants V process evolution, classification angiosperms. Define place kind lily of the valley May V system vegetable peace (Department, Class, family, genus). -
Complication plants V process evolution, classification angiosperms. Define place kind lily of the valley May V system vegetable peace (Department, Class, family, genus). -
Complication mammals V process evolution. Define place kind common fox V system animal peace(type, Class, squad, family, genus). The phylum Chordata includes the subphylum Cranial, or Vertebrate. -
Vertebrates, their classification. Complication mammals V process evolution. Define place kind common fox V system animal peace(type, Class, squad, family, genus). -
Vertebrates, their classification. Complication mammals V process evolution. Define place kind common fox V system animal peace(type, Class, squad, family, genus). -
Classification plants For example angiosperms plants families(Solanaceae, Rosaceae
Department Angiosperms consists of two classes: Dicotyledons and Monocots. For dicotyledons it is typical -
Currently, the dominant position on Earth is occupied by Department Angiosperms (Tsvetkov) plants, considered the most evolutionarily advanced and defining view most modern biotopes. -
Classification plants For example angiosperms. Select from herbarium specimens plants families(Solanaceae, Rosaceae, Legumes, etc.), by what signs do you recognize them? Department Angiosperms consists of two classes: Dicotyledons and Monocots.
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