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 flora(department, class, family, genus).
The complication of plants in the process of evolution proceeded in the following directions:
cell differentiation, the formation of tissues that differ in structure and functions: educational, integumentary, mechanical, suction, conductive, assimilation (carrying out photosynthesis);
emergence of specialized organs: shoot, including stem, leaves, generative organs, and root;
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 reproduction by seeds, which did not require the presence of water for fertilization;
special adaptations in angiosperms to attract pollinating insects.
The angiosperm division includes the dicotyledonous and monocotyledonous classes. The following systematic categories are studied in the school course: family, genus, species. May lily of the valley classification:
Department of angiosperms, or flowering
Monocot class
lily family
Genus lily of the valley
May lily of the valley view
3. Using knowledge of immunity, explain the purpose for which a person is vaccinated and sera are administered. How can you increase the protective properties of the body? How to protect yourself from HIV infection and AIDS?
Immunity is a protective reaction of the body to foreign bodies and substances. Immunity is natural: congenital or acquired during life.
To develop resistance to the disease, artificial immunity is formed by introducing a weakened culture of microorganisms to a person. At the same time, antibodies are produced in the body. This allows the body to successfully fight off the infection in the event of a subsequent infection. Such artificial immunity is called active. The first vaccination in history was smallpox.
If infection or penetration of poison (with a snake bite) has already occurred, a person is injected with a serum containing ready-made antibodies that help neutralize adverse impact. Immunity resulting from the introduction of serum is called passive.
The protective properties of the body increase with hardening, physical education, proper nutrition, and the content of a sufficient amount of vitamins in food. Less likely to get sick people with a balanced nervous system enthusiastic, optimistic.
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, one should categorically exclude drugs, casual sex from life, and not abuse alcohol, which deprives a person of the ability to control his actions. Do not allow the use of common syringes, needles, and in the hairdresser - a razor, manicure accessories that have not been disinfected (for this you need to soak in alcohol or cologne for 25 minutes).
1. Biosphere - a global ecosystem, its boundaries. Living matter of the biosphere. The role of man 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 found in the deepest ocean trenches, in oil fields (anaerobic bacteria that feed 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 habitation 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 tremendous impact on all processes, participating in the processes of matter and energy circulation. Suffice it to recall the formation of oxygen reserves in the atmosphere and the ozone screen, limestone reserves in the oceans.
The stability of the communities included in the biosphere depends on their species diversity. The decline in the number of one species does not have a serious impact on the community as a whole, if the role of the retired species is "taken over" by the available existing species with similar needs. Therefore, the conservation 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 protection. Since the significant harm caused by a person 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 sustainable development of civilization and conservation of nature.
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 earlier they were classified as bacteria, fungi and lichens. Now they are separated into independent kingdoms), and mosses, ferns, gymnosperms and angiosperms are classified as higher.
In the evolution of lower organisms, 2 periods are distinguished, which differ significantly from each other in the organization of the cell. During 1 period, organisms similar to bacteria and blue-green algae dominated. The cells of these life forms did not have typical organelles (mitochondria, chloroplasts, Golgi apparatus, etc.). The cell nucleus was not limited by the nuclear membrane (this is a prokaryotic type of cellular organization). The 2nd period was associated with the transition of lower plants (algae) to an autotrophic type of nutrition and with the formation of a cell with all typical organelles (this is a eukaryotic type of cellular organization, which was preserved at subsequent stages in the 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 the multicellular are filamentous algae (ulotrix), which do not have any branching of their body. Their body is a long chain of individual cells. Other multicellular algae are dissected by a large number of outgrowths, so their body branches (in hara, in fucus).
Multicellular algae, in connection with their autotrophic (photosynthetic) activity, have developed in the direction of increasing the 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 the beginning of a new generation is given by 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 lifestyle to a terrestrial one. The primary terrestrial organisms were psilophytes, which were preserved as fossils in the Silurian and Devonian deposits. The structure of these plants is more complex compared to algae: a) they had special organs for attaching to the substrate - rhizoids; b) stem-like organs with wood surrounded by bast; c) rudiments of conductive 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 the cycle of their individual development. A gametophyte is a whole green plant capable of self-feeding. The sporophyte is represented by a box (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-ground lifestyle turned out to be inappropriate, therefore, mosses have become a special branch of the evolution of higher plants and have not yet produced perfect groups of plants. This was also facilitated by the fact that the gametophyte, in comparison with the sporophyte, had a dinner heredity (haploid (1n) set of chromosomes). This line in the evolution of higher plants is called gametophyte.
The second line of evolution on the way 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, organs of sporulation (in ferns) or fruiting (in angiosperms). Sporophyte cells have a diploid set of chromosomes, because they develop from a diploid zygote. The gametophyte is greatly reduced and 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 by the germination of pollen. It consists of one vegetative and one generative cell. When pollen germinates from a generative cell, 2 sperm are produced. These 2 male germ cells are involved in double fertilization in angiosperms. A fertilized egg gives rise to a new generation of plants - the sporophyte. The progress of angiosperms is due to the improvement of the reproduction function.
Algae are the original inhabitants of the seas, widespread in fresh waters. Higher plants are terrestrial plants that have mastered the land, as well as fresh and brackish water bodies. Only a very few representatives of higher plants have adapted to life in sea water.
The emergence of plants on 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 terrestrial 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 "primary goloros" - Psilophyton princeps. The plant was a system of forked axes covered with small spines (Fig. 11b). Sporangia were located at the ends of arcuately curved drooping branches. The unusual appearance of the goloros did not allow it to be attributed to any of the plant taxa known at that time, and for a long time he remained a mystery of nature.
In 1912, rhynia ( Rhynia), which differs from the goloros 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 - kuksonia.
These and other ancient plants similar to them were previously combined into one taxon called psilophytes ( psilophyta). However, the discovered plants most likely were representatives of groups that had already diverged far enough in the process of rapid evolution. It's not very significant. It is important that the study of the remains of all the most ancient terrestrial 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 in late XIX and the beginning of the 20th century, attempts were made to create hypothetical models of the ancestors of higher plants. The greatest attention of researchers has attracted telome theory structure of the most 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 goloros, rhynia, cooksonia and other plants that existed in the Silurian and Devonian proves that they were sporophytes, the main purpose of which is the formation of spores. To disperse the spores, the sporangia must be raised above the substrate. Consequently, the development of the sporophyte must have been accompanied by an increase in its size. This required the necessary amount of food 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 the surface, which occurred with the slow growth of the sporophyte, was achieved by its division, the simplest method of which was the forked branching of the axial organs. Their terminal branches were called telomes (from the Greek telos - end), and the parts connecting them - mesomas (from the Greek mesos - middle). Telomes were of two types: fertile, with sporangia at the top, and sterile that perform the function of photosynthesis.
The underground part of the plant also forked branched. Numerous rhizoids developed on the surface of terminal branches. These branches were later named rhizomoids(Takhtadzhyan, 1954). Thus, according to the telome theory, the main organs of the most ancient terrestrial plants were telomes, rhizomoids, and mesomes connecting them (Fig. 12).
Rice. 12. Structure diagram
hypothetical
sporophyte of a higher plant.
Designations: mz - me-
zom, r - rhizoids,
rzm - rhizomoid, cn -
sporangium, s.t - sterile
body, f.t -
fertile body
The study of paleobotanical material, mainly ferns, allowed G. Potonier (1912) to conclude that forked or dichotomous branching was the source for other types of branching (Fig. 13).
Rice. 13. Scheme of branching evolution of higher sporophytes
plants: A - equal dichotomy (isotomy); B - unequal
dichotomy (anisotomy); B - dichopodium; G - monopodium;
D - sympodium
At dichotomous branching splits (bifurcates) the growth zone located at the top of each axis. 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 rate, and then their tops 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. 13B), with the formation of a zigzag curved main axis of the plant.
From dichotomous branching, 2 types of lateral branches have developed.
The straightening of 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, 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 beginnings of the axes of the third order were laid in the same way, and so on.
In the most ancient plants, the second type of lateral branching was also revealed - sympodial(Fig. 13 E). In this case, the growth of the main axis stopped over time, and the lateral branch of the second order of branching, located near its top, straightened up, displaced the end of the main axis to the side, and itself began to grow in the direction in which the main axis used to grow. Then its growth also stopped, and its apex moved aside was replaced by a new lateral branch of the third order of branching, etc. As a result, a straight or cranked axis appeared, which was a system of axes of different branching orders growing one on top of the other.
Branching was not the only way to increase the surface of the sporophyte.
The telomes were cylindrical and had an oblique-vertical orientation. Only a small part of their surface was turned to the sun's rays. An increase in the size of the light-receiving surface was achieved by the formation of flattened organs - leaves, oriented more or less horizontally. Axial organs bearing leaves have turned into stems. This is how leafy plants arose. In appearance, they differ greatly. One of them, called microphilic(from the Greek mikros - small and phyllon - leaf), have numerous small leaves, others called macrophilic(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 macrophyllic line of plant evolution was determined by several interrelated processes (Fig. 14 B).
1. aggregation, or crowding, of telomes, which occurs as a result of shortening and sometimes reduction of mesomes;
2. "reversal", due to the uneven development of sterile bodies, while one of them, with unlimited growth in length, became a stem, and the other body of the same dichotomy, greatly lagging behind 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. fourteen. 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 a comprehensive one became two-sided, and then one-sided. Clustering of telomes, their branching in one plane, coalescence by edges and reduction up to the disappearance of sporangia located on some telomes eventually 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 a 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 at high humidity of the environment. In the process of evolution, the size of the leaves decreased due to the weakening of their growth, they acquired adaptations that limited transpiration. All this expanded the adaptive capabilities of plants. Of modern plants, macrophyllia is characteristic not only of ferns, but also of seed plants.
The relationship of plastic and energy metabolism.
Protection against ionizing radiation with the help of screens.
Screen- closed chamber, the requirements for which are as follows:
When operating at full power, the energy leakage should not exceed σ adm
Unit control - remote
Door interlock application (automatically relieves tension when doors are opened)
Ventilation, inspection holes, control handles must be protected from energy leakage in environment
3. Determine at what distance from the ground electrode the voltage will not exceed 36V. A short circuit to a grounded case occurred in a network with the following parameters:
1) metabolic value: the body receiving O, nutrients for building cells and energy for life processes.
2) Metabolic functions: transport of nutrients and O from the external environment into the body, the participation of these substances in complex metabolic reactions with the absorption and release of energy, and the removal of decay products to the outside.
3) The relationship of plastic and energy metabolism: plastic exchange supplies for energy metabolism organic matter and enzymes, and energy metabolism supplies for plastic - energy, without which synthesis reactions cannot proceed. Violation of one of the types of cellular metabolism leads to disruption of all vital processes, to the death of the organism.
1) the main features of plants of different departments.
Almost all plant organisms are capable of photosynthesis - the formation of organic molecules from inorganic ones due to the energy of light.
Plants have specific pigments contained in plastids: chlorophyll is green, carotenoids are red, orange-yellow.
The vital processes of a plant organism are regulated by special plant hormones - phytohormones. Their interaction provides growth, development and other physiological processes occurring in plants.
Plant cells are surrounded by a thick cell wall. It is formed mainly by cellulose.
The metabolic product is cell sap, which increases intracellular pressure. As a result, plant tissues acquire high strength.
Plants are characterized by unlimited growth: they increase in size throughout their life.
2) Signs of complication of plant organization.
The emergence of multicellular algae
The appearance of stems and leaves in mosses
The appearance of roots in ferns
The appearance of angiosperms in which the seed is surrounded by a fruit or capsule
3) Reasons for evolution.
· Natural selection . Plants that are stronger and more resistant to climatic conditions and further development survive
· Heredity. The ability of organisms to transfer their characteristics and properties unchanged to daughter organisms.
· Variability. The ability of organisms to acquire new features and properties in the process of individual development.
· Struggle for existence. The set of diverse relationships between living organisms and the environment.
The science that studies the plant world is called botany. For the entire time of the existence of mankind on planet Earth, knowledge about plants has gradually accumulated. Even when collecting roots, seeds, bulbs and herbs, our ancestors learned to distinguish poisonous crops from edible and medicinal ones, and also began to determine the areas of their growth, the features of preparation or storage. This and other knowledge in the field of botany is extremely important for mankind.
The world
Botany for modern humanity is a science that consists of many branches. It is aimed at studying each plant individual separately, as well as at studying their communities that form forests, steppes, meadows, etc. Botanical sciences study the detailed composition of all parts of plants, classify them according to various characteristics, work on the possibility of using especially valuable crops in the economy . In addition, various studies are being carried out on the cultivation of plants hitherto unknown to the average person. Of course, a particularly urgent problem for botany is the issue of protection. natural resources, and in particular - extremely rare species of vegetation.
Research work carried out using a variety of experimental methods and technical devices. Botany is also closely related to other sciences, including soil science, forestry, zoology, agronomy, geology, chemistry, and medicine.
The complication of plants in the process of evolution
The evolution of the plant world began many millions of years ago.
The very first plant-type organisms appeared on our planet back in the Archean macaw. They were unicellular and multicellular prokaryotic organisms, and belonged to blue-green algae. Such plants showed the ability to photosynthesis, which was accompanied by the release of oxygen. Blue-green algae enriched the Earth's atmosphere with oxygen, necessary for all kinds of aerobic organisms.
At the stage of the protozoic era, green and red algae reigned on our planet. Such cultures are considered as the lowest plants, their body is not divided into sections and does not possess specialized tissues.
In the Paleozoic, the highest representatives of the flora began to appear on Earth, which are called psilophytes or rhinophytes. Such cultures already had shoots, but they did not grow roots or leaves. Their reproduction took place with the help of spores. Such plants were located on the surface of the earth, or led a semi-aquatic lifestyle.
Toward the end of the Paleozoic, mossy and fern-like plants appeared on Earth. At the same time, mosses developed stems and first leaves, while ferns developed roots.
At the Carboniferous stage, seed ferns arose on our planet, which became the precursors for gymnosperms. And in the Permian period of the Paleozoic, the very first gymnosperms cultures appeared that could reproduce by seeds that were not protected by the fruit.
In the Jurassic period, the first angiosperms are formed. Such plants have already acquired flowers in which pollination, fertilization is carried out, and then the embryo and fruit are formed. The seeds of such crops are protected by pericarp.
Now, in the Cenozoic era, modern angiosperms, as well as gymnosperms, reign on Earth, and most of the higher spore plants are biologically regressing. However, the process of plant evolution is not over. It's an endless process.
The world around us, classification of plants
Over the entire period of the existence of botany, scientists have repeatedly tried to create systems for classifying plants, combining them into groups according to various common features. The very first attempts of this kind date back to the end of the eighteenth century, at that time humanity was just beginning to grope for natural connections between various living organisms.
The pioneer in this area was the French botanist Adanson, who tried to distribute plants into groups, taking into account the maximum number of signs.
One of Adanson's contemporaries, Jussieu, created his own classification system, in which he did not count signs individual representatives flora, and compared them and weighed them.
More successful attempts to classify plants into groups date back to the nineteenth century, at which time the Brown system was created, as well as the systems of Eichler and Decandole. All these options had their drawbacks, so they can only be considered in the historical plane.
The modern system of plant classification combines plants with similar characteristics into groups that are called species. In the event that a species has no close relatives, it forms a monotypic genus.
In general, plant taxonomy is rigorous hierarchical system, consisting of groups of different ranks. Thus, families are orders, and orders are classes.
Now scientists are considering four groups of plants - green algae, bryophytes, vascular spores, and seed plants. The first group includes green and charophytic algae. Bryophytes include hepatic and anthocerotic mosses, as well as bryophytes.
Vascular spores are represented by lycopsform, fern-like and horsetail. The group of higher plants (seeds) includes sagoviform, ginkgoiform, coniferous, and gnetoform cultures.
Various plants make up the world around us in many ways, their evolution lasted for several million years and is still ongoing, and the classification of such crops into groups allows scientists to closely monitor the constant evolutionary changes.