To what depth in the World Ocean does the photosynthetic zone extend? Efficiency of photosynthesis in terrestrial and marine ecosystems. Cyanobacteria are able to “short-circuit” the process of photosynthesis Food chains and pyramids
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Lesson 2. Biomass of the biosphere
Analysis of test work and grading (5-7 min).
Oral repetition and computer testing (13 min).
Land biomass
The biomass of the biosphere is approximately 0.01% of the mass of inert matter of the biosphere, with plants accounting for about 99% of the biomass, and about 1% for consumers and decomposers. The continents are dominated by plants (99.2%), the oceans are dominated by animals (93.7%)
The biomass of land is much greater than the biomass of the world's oceans, it is almost 99.9%. This is explained by a longer life expectancy and the mass of producers on the surface of the Earth. In terrestrial plants, the use of solar energy for photosynthesis reaches 0.1%, and in the ocean it is only 0.04%. The biomass of different areas of the Earth's surface depends on climatic conditions - temperature, amount of precipitation. Severe climatic conditions tundra -, low temperatures permafrost , short cold summer formed peculiar plant communities with little biomass. The vegetation of the tundra is represented by lichens, mosses, creeping dwarf trees, herbaceous vegetation that can withstand such extreme conditions . Taiga biomass, then mixed and deciduous forests gradually increases. The steppe zone gives way to subtropical and tropical vegetation
, where living conditions are most favorable, biomass is maximum. The top layer of soil has the most favorable water, temperature, and gas conditions for life. Vegetation cover provides organic matter to all soil inhabitants - animals (vertebrates and invertebrates), fungi and great amount bacteria. Bacteria and fungi are decomposers; they play a significant role in the cycle of substances in the biosphere, mineralizing
organic substances. “The great gravediggers of nature” - this is what L. Pasteur called bacteria.
Biomass of the world's oceans Hydrosphere The “water shell” is formed by the World Ocean, which occupies about 71% of the surface globe , and land reservoirs - rivers, lakes - about 5%. There is a lot of water in and glaciers. Due to the high density of water, living organisms can normally exist not only at the bottom, but also in the water column and on its surface. Therefore, the hydrosphere is populated throughout its entire thickness, living organisms are represented benthos, plankton And nekton.
Benthic organisms(from the Greek benthos - depth) lead a bottom-dwelling lifestyle, living on the ground and in the ground. Phytobenthos is formed by various plants - green, brown, red algae, which grow at different depths: at shallow depths, green, then brown, deeper - red algae, which are found at a depth of up to 200 m. Zoobenthos is represented by animals - mollusks, worms, arthropods, etc. Many have adapted to life even at a depth of more than 11 km.
Planktonic organisms(from the Greek planktos - wandering) - inhabitants of the water column, they are not able to move independently over long distances, they are represented by phytoplankton and zooplankton. Phytoplankton includes unicellular algae and cyanobacteria, which are found in sea waters to a depth of 100 m and are the main producer of organic substances - they have an unusually high speed reproduction. Zooplankton are marine protozoa, coelenterates, and small crustaceans. These organisms are characterized by vertical daily migrations; they are the main food source for large animals - fish, baleen whales.
Nektonic organisms(from Greek nektos - floating) - inhabitants aquatic environment, capable of actively moving through the water column, covering long distances. These are fish, squid, cetaceans, pinnipeds and other animals.
Written work with cards:
1. Compare the biomass of producers and consumers on land and in the ocean.
2. How is biomass distributed in the World Ocean?
3. Describe terrestrial biomass.
4. Define the terms or expand the concepts: nekton; phytoplankton; zooplankton; phytobenthos; zoobenthos; percentage of the Earth's biomass from the mass of inert matter of the biosphere; percentage of plant biomass from the total biomass of terrestrial organisms; percentage of plant biomass from the total biomass of aquatic organisms.
Card on the board:
1. What is the percentage of the Earth’s biomass from the mass of inert matter in the biosphere?
2. What percentage of the Earth's biomass comes from plants?
3. What percentage of the total biomass of terrestrial organisms is plant biomass?
4. What percentage of the total biomass of aquatic organisms is plant biomass?
5. What % of solar energy is used for photosynthesis on land?
6. What % of solar energy is used for photosynthesis in the ocean?
7. What are the names of the organisms that inhabit the water column and are transported sea currents?
8. What are the names of the organisms that inhabit the ocean soil?
9. What are the names of organisms that actively move in the water column?
Test:
Test 1. The biomass of the biosphere from the mass of inert matter of the biosphere is:
Test 2. The share of plants from the Earth's biomass is:
Test 3. Biomass of plants on land compared to the biomass of terrestrial heterotrophs:
2. Is 60%.
3. Is 50%.
Test 4. Plant biomass in the ocean compared to the biomass of aquatic heterotrophs:
1. Prevails and accounts for 99.2%.
2. Is 60%.
3. Is 50%.
4. The biomass of heterotrophs is less and amounts to 6.3%.
Test 5. The average use of solar energy for photosynthesis on land is:
Test 6. The average use of solar energy for photosynthesis in the ocean is:
Test 7. Ocean benthos is represented by:
Test 8. Ocean nekton is represented by:
1. Animals actively moving in the water column.
2. Organisms that inhabit the water column and are transported by sea currents.
3. Organisms living on the ground and in the ground.
4. Organisms living on the surface film of water.
Test 9. Ocean plankton is represented by:
1. Animals actively moving in the water column.
2. Organisms that inhabit the water column and are transported by sea currents.
3. Organisms living on the ground and in the ground.
4. Organisms living on the surface film of water.
Test 10. From the surface to the depths, algae grow in the following order:
1. Shallow brown, deeper green, deeper red up to - 200 m.
2. Shallow red, deeper brown, deeper green up to - 200 m.
3. Shallow green, deeper red, deeper brown up to - 200 m.
4. Shallow green, deeper brown, deeper red - up to 200 m.
The principle of the oxygen and radiocarbon method for determining primary production (photosynthesis rate). Tasks to determine destruction, gross and net primary production.
What mandatory conditions must exist on planet Earth for the formation of the ozone layer. What UV ranges does the ozone screen block?
What forms of ecological relationships negatively affect species.
Amensalism - one population negatively affects another, but itself does not experience either negative or positive influence. A typical example is high tree crowns that inhibit the growth of low-growing plants and mosses by partially blocking access to sunlight.
Allelopathy is a form of antibiosis in which organisms exert mutual bad influence on each other, due to their vital factors (for example, secretions of substances). Found mainly in plants, mosses, and fungi. Moreover, the harmful influence of one organism on another is not necessary for its life and does not bring it any benefit.
Competition is a form of antibiosis in which two types of organisms are biological enemies inherently (usually due to the common food supply or disabilities for reproduction). For example, between predators of the same species and the same population or different types eating the same food and living in the same territory. In this case, harm caused to one organism benefits another, and vice versa.
Ozone is formed when ultraviolet radiation from the sun bombards oxygen molecules (O2 -> O3).
The formation of ozone from ordinary diatomic oxygen requires quite a lot of energy - almost 150 kJ for each mole.
It is known that the bulk of natural ozone is concentrated in the stratosphere at an altitude of 15 to 50 km above the Earth's surface.
Photolysis of molecular oxygen occurs in the stratosphere under the influence ultraviolet radiation with a wavelength of 175-200 nm and up to 242 nm.
Ozone formation reactions:
О2 + hν → 2О.
O2 + O → O3.
Radiocarbon modification comes down to the following. The carbon isotope 14C is added to the water sample in the form of sodium carbonate or sodium bicarbonate with known radioactivity. After some exposure of the bottles, the water from them is filtered through a membrane filter and the radioactivity of plankton cells is determined on the filter.
The oxygen method for determining the primary production of reservoirs (flask method) is based on determining the intensity of photosynthesis of planktonic algae in bottles installed in a reservoir at different depths, as well as under natural conditions - by the difference in the content of oxygen dissolved in water at the end of the day and at the end of the night.
Tasks to determine destruction, gross and net primary production.??????
The euphotic zone is the upper layer of the ocean, the illumination of which is sufficient for the process of photosynthesis to occur. The lower boundary of the photic zone passes at a depth that reaches 1% of light from the surface. It is in the photic zone that phytoplankton live, as well as radiolarians, plants grow and most aquatic animals live. The closer to the Earth's poles, the smaller the photic zone. Thus, at the equator, where the sun’s rays fall almost vertically, the depth of the zone is up to 250 m, while in Bely it does not exceed 25 m.
The efficiency of photosynthesis depends on many internal and external conditions. For individual leaves placed in special conditions, the efficiency of photosynthesis can reach 20%. However, the primary synthetic processes occurring in the leaf, or rather in the chloroplasts, and the final harvest are separated by a string of physiological processes in which a significant part of the accumulated energy is lost. In addition, the efficiency of light energy absorption is constantly limited by the factors already mentioned environment. Due to these limitations, even in the most advanced varieties of agricultural plants under optimal growth conditions, the efficiency of photosynthesis does not exceed 6-7%.
Oceans and seas occupy 71% (more than 360 million km2) of the Earth's surface. They contain about 1370 million km3 of water. Five huge oceans - Pacific, Atlantic, Indian, Arctic and Southern - are connected to each other through the open sea. In some parts of the Arctic and Southern Oceans, a permanently frozen continental shelf has formed, extending from the coast (shelf ice). In slightly warmer areas, the sea freezes only in winter, forming pack ice (large floating ice fields up to 2 m thick). Some marine animals use the wind to travel across the sea. In physalia (“ Portuguese man-of-war") there is a gas-filled bubble that helps catch the wind. Yantina releases air bubbles that serve as her float raft.The average depth of water in the oceans is 4000 m, but in some ocean depressions it can reach 11 thousand m. Under the influence of wind, waves, tides and currents, ocean water is in constant motion. Waves raised by the wind do not affect deep water masses. This is done by the tides, which move water at intervals corresponding to the phases of the moon. Currents carry water between oceans. Surface currents, moving, slowly rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.
Ocean bottom:
Most of The ocean floor is a flat plain, but in some places mountains rise thousands of meters above it. Sometimes they rise above the surface of the water in the form of islands. Many of these islands are active or extinct volcanoes. Through central part At the bottom of a number of oceans there are mountain ranges. They are constantly growing due to the outpouring of volcanic lava. Each new flow that carries rock to the surface of underwater ridges forms the topography of the ocean floor.
The ocean floor is mostly covered with sand or silt - they are brought by rivers. In some places there are hot springs, from which sulfur and other minerals are deposited. The remains of microscopic plants and animals sink from the surface of the ocean to the bottom, forming a layer of tiny particles (organic sediment). Under pressure from overlying water and new sediment layers, the loose sediment slowly turns into rock.
Oceanic zones:
In depth, the ocean can be divided into three zones. In the sunny surface waters above - the so-called photosynthetic zone - most ocean fish swim, as well as plankton (a community of billions of microscopic creatures that live in the water column). Beneath the photosynthesis zone lie the dimly lit twilight zone and the deep, cold waters of the gloom zone. Fewer life forms are found in the lower zones - mainly carnivorous (predatory) fish live there.
In most of the ocean water the temperature is approximately the same - about 4 °C. As a person dives deeper, the pressure of water on him from above constantly increases, making it difficult to move quickly. At greater depths, in addition, the temperature drops to 2 °C. The light becomes less and less until finally, at a depth of 1000 m, complete darkness reigns.
Life at the surface:
Vegetable and animal plankton in the photosynthesis zone - it is food for small animals, such as crustaceans, shrimp, and juveniles starfish, crabs and others sea creatures. Far from protected coastal waters animal world less diverse, but many fish live here and large mammals- for example, whales, dolphins, porpoises. Some of them (baleen whales, giant sharks) feed by filtering water and ingesting plankton contained in it. Others (white sharks, barracudas) prey on other fish.
Life in the depths of the sea:
In the cold, dark waters of the ocean depths, hunting animals are able to detect the silhouettes of their victims in the dimmest light, barely penetrating from above. Here, many fish have silvery scales on their sides: they reflect any light and camouflage the shape of their owners. Some fish, flat on the sides, have a very narrow silhouette, barely noticeable. Many fish have huge mouths and can eat prey that is larger than them. Howliods and hatchetfish swim with their large mouths open, grabbing whatever they can along the way.
From the surface to the very bottom, the ocean is alive with the life of a variety of animals and plants. Just like on land, almost all life here depends on plants. The main food is billions of microscopic plants called phytoplankton, which are carried by currents. Using the sun's rays, they create food for themselves from sea, carbon dioxide and minerals. During this process, called photosynthesis, phytoplankton produce 70% of atmospheric oxygen. Phytoplankton consists mainly of small plants called diatoms. In a cup sea water there can be up to 50 thousand. Phytoplankton can only live near the surface where there is enough light for photosynthesis. Another part of plankton - zooplankton - does not participate in photosynthesis and therefore can live deeper. Zooplankton are tiny animals. They feed on phytoplankton or eat each other. Zooplankton includes juveniles - larvae of crabs, shrimp, jellyfish and fish. Most of them do not look like adults at all. Both types of plankton serve as food for fish and other animals - from small jellyfish to huge whales and sharks. The amount of plankton varies from place to place and from season to season. Most plankton are found on the continental shelf and at the poles. Krill is a type of zooplankton. Most krill are found in the Southern Ocean. Plankton also lives in fresh waters. If you can, look at a drop of water from a pond or river or a drop of sea water under a microscope
Food chains and pyramids
Animals eat plants or other animals and themselves serve as food for other species. More than 90% of sea inhabitants end their lives in the stomachs of others. All life in the ocean is thus connected into a huge food chain, starting with phytoplankton. To feed one large animal, you need many small ones, so there are always fewer large animals than small ones. This can be depicted as a food pyramid. To increase its weight by 1 kg, tuna needs to eat 10 kg of mackerel. To obtain 10 kg of mackerel you need 100 kg of young herring. For 100 kg of young herring you need 1000 kg of zooplankton. To feed 1000 kg of zooplankton, you need 10,000 kg of phytoplankton.
ocean floors
The thickness of the ocean can be divided into layers, or zones, according to the amount of light and heat that penetrates from the surface (see also the article ““). The deeper the zone, the colder and darker it is. All plants and most animals are found in the top two zones. The sunny zone gives life to all plants and a wide variety of animals. Only a little light from the surface penetrates into the twilight zone. The largest inhabitants here are fish, squid and octopuses. In the dark zone it is about 4 degrees Celsius. Animals here feed mainly on the “rain” of dead plankton that falls from the surface. The abyssal zone is completely dark and icy cold. The few animals that live there live under constant high pressure. Animals are also found in ocean depressions, at depths of more than 6 km from the surface. They feed on what falls from above. About 60% deep sea fish have their own glow to find food, detect enemies and give signals to relatives.
Coral reefs
Coral reefs are found in shallow, warm, clear tropical waters. They are made up of the skeletons of small animals called coral polyps. When old polyps die, new ones begin to grow on their skeletons. The oldest reefs began to grow many thousands of years ago. One type of coral reef is an atoll, which is shaped like a ring or a horseshoe. The formation of atolls is shown below. Coral reefs began to grow around the volcanic island. After the volcano subsided, the island began to sink to the bottom. The reef continues to grow as the island sinks. A lagoon forms in the middle of the reef salt Lake). When the island sank completely, the coral reef formed an atoll - a ring reef with a lagoon in the middle. Coral reefs are more diverse in life than other parts of the ocean. A third of all ocean fish species are found there. The largest is Bolshoi barrier reef on east coast Australia. It stretches for 2027 km and shelters 3000 species
The biosphere (from the Greek “bios” - life, “sphere” - ball) as a carrier of life arose with the appearance of living beings as a result evolutionary development planets. The biosphere refers to the part of the Earth's shell inhabited by living organisms. The doctrine of the biosphere was created by academician Vladimir Ivanovich Vernadsky (1863-1945). V.I. Vernadsky is the founder of the doctrine of the biosphere and the method of determining the age of the Earth based on the half-life of radioactive elements. He was the first to reveal the enormous role of plants, animals and microorganisms in the movement of chemical elements earth's crust.
The biosphere has certain boundaries. The upper boundary of the biosphere is located at an altitude of 15-20 km from the Earth's surface. It takes place in the stratosphere.
The bulk of living organisms are located in the lower air shell - the troposphere. The lowest part of the troposphere (50-70 m) is the most populated. The lower boundary of life passes through the lithosphere at a depth of 2-3 km. Life is concentrated mainly in the upper part of the lithosphere - in the soil and on its surface.
Water shell planets (hydrosphere) occupies up to 71% of the Earth's surface. If we compare the size of all geospheres, we can say that the lithosphere has the largest mass, the atmosphere the smallest. The biomass of living beings is small compared to the size of geospheres (0.01%). IN different parts The density of life in the biosphere is not the same.
Largest quantity organisms are located at the surface of the lithosphere and hydrosphere. The biomass content also varies by zone. Tropical forests have the maximum density, while Arctic ice and high mountain areas have the lowest density. Biomass. The organisms that make up the biomass have a tremendous ability to reproduce and spread throughout the planet (see section “Struggle for existence”). Reproduction determines density of life. It depends on the size of the organisms and the area required for life. The density of life creates a struggle among organisms for space, food, air, and water. In progress natural selection and fitness is concentrated in one area
a large number of
organisms with the highest density of life. Land biomass. On the Earth's land, starting from the poles to the equator, biomass gradually increases. The greatest concentration and diversity of plants occurs in humid
As a living environment, soil has a number of specific features, is rich in protozoa - amoebas, flagellates, ciliates. Even Charles Darwin drew attention to the role of earthworms, which loosen the soil, swallow it and soak it with gastric juice. In addition, ants, ticks, moles, marmots, gophers and other animals live in the soil. All inhabitants of the soil do a lot of soil-forming work and participate in creating soil fertility. Many soil organisms take part in the general cycle of substances occurring in the biosphere.
Biomass of the World Ocean.
The Earth's hydrosphere, or the World Ocean, occupies more than 2/3 of the planet's surface. Water has special properties that are important for the life of organisms. Its high heat capacity makes the temperature of oceans and seas more uniform, moderating extreme temperature changes in winter and summer. Physical properties And chemical composition Ocean waters are very constant and create an environment favorable for life. The ocean accounts for about 1/3 of the photosynthesis that occurs on the entire planet.
Single-celled algae and tiny animals suspended in water form plankton. Plankton is of primary importance in the nutrition of ocean fauna.
In the ocean, in addition to plankton and free-swimming animals, there are many organisms attached to the bottom and crawling along it. The inhabitants of the bottom are called benthos.
There is 1000 times less living biomass in the World Ocean than on land. In all parts of the World Ocean there are microorganisms that decompose organic matter into mineral matter.
The circulation of substances and the transformation of energy in the biosphere. Plant and animal organisms, being in relationship with the inorganic environment, are included in the continuously occurring cycle of substances and energy in nature.
Carbon is found naturally in rocks in the form of limestone and marble. Most carbon is found in the atmosphere as carbon dioxide. Out of thin air carbon dioxide absorbed by green plants during photosynthesis. Carbon is included in the cycle due to the activity of bacteria that destroy the dead remains of plants and animals.
When plants and animals decompose, nitrogen is released in the form of ammonia. Nitrophizing bacteria convert ammonia into salts of nitrous and nitric acids, which are absorbed by plants. In addition, some nitrogen-fixing bacteria are capable of assimilating atmospheric nitrogen.
Large reserves of phosphorus contain rocks. When destroyed, these rocks release phosphorus to the ground ecological systems, however, some of the phosphates are drawn into the water cycle and carried out to the sea. Together with dead residues, phosphates sink to the bottom. One part of them is used, and the other is lost in deep sediments. Thus, there is a discrepancy between phosphorus consumption and its return to the cycle.
As a result of the cycle of substances in the biosphere, continuous biogenic migration of elements occurs. Necessary for the life of plants and animals chemical elements pass from the environment into the body. When organisms decompose, these elements return to the environment, from where they again enter the body.
Participate in the biogenic migration of elements various organisms, including humans.
The role of man in the biosphere. Man is part of the biomass of the biosphere - for a long time was directly dependent on surrounding nature. With the development of the brain, man himself becomes a powerful factor in further evolution on Earth. Mastery of Man various forms energy - mechanical, electrical and atomic - contributed to a significant change in the earth's crust and biogenic migration of atoms. Along with benefits, human intervention in nature often brings harm to it. Human activities often lead to disruption natural patterns. Disruption and change of the biosphere are of serious concern. In this regard, in 1971, UNESCO (United Nations Educational, Scientific and Cultural Organization), which includes the USSR, adopted the International Biological Program (IBP) “Man and the Biosphere”, which studies changes in the biosphere and its resources under human influence.
Article 18 of the USSR Constitution says: “In the interests of present and future generations, the USSR adopts necessary measures for protection and scientifically based, rational use earth and its subsoil, water resources, flora and fauna, to maintain clean air and water, ensure reproduction natural resources and improving the human environment."
| First nucleotide | Second nucleotide | Third nucleotide |
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phenylalanine | |||||
meaningless | tryptophan |
||||
histidine | glutamine (glun) | ||||
isoleucine | methionine | ||||
asparagine (aspn) | |||||
aspartic acid (asp) | glutamic acid | ||||
There are several types of cytological tasks.
1. In the topic “Chemical organization of the cell” they solve problems on constructing the second helix of DNA; determining the percentage of content of each nucleotide, etc., for example, task No. 1. On a section of one DNA chain there are nucleotides: T - C - T-A - G - T - A - A - T. Determine: 1) the structure of the second chain, 2) the percentage of content of each nucleotide in a given segment.
Solution: 1) The structure of the second chain is determined by the principle of complementarity. Answer: A - G - A - T - C - A - T -T - A.
2) There are 18 nucleotides (100%) in two chains of this DNA segment. Answer: A = 7 nucleotides (38.9%) T = 7 - (38.9%); G = 2 - (11.1%) and C = 2 - (11.1%).
II. In the topic “Metabolism and energy conversion in the cell,” they solve problems to determine the primary structure of a protein from the DNA code; gene structure based on the primary structure of the protein, for example, task No. 2. Determine the primary structure of the synthesized protein if on a section of one DNA chain the nucleotides are located in the following sequence: GATACAATGGTTCGT.
- Without disturbing the sequence, group the nucleotides into triplets: GAT - ACA - ATG - GTT - CGT.
- Construct a complementary chain of mRNA: CUA - UGU - UAC - CAA - GC A.
PROBLEM SOLVING
3. According to the table genetic code identify the amino acids encoded by these triplets. Answer: lei-cis-tir-glu-ala. Similar types of problems are solved in a similar way based on the corresponding patterns and sequence of processes occurring in the cell.
Genetic problems are solved in the topic “Basic patterns of heredity.” These are problems on monohybrid, dihybrid crossing and other patterns of heredity, for example task No. 3. When black rabbits are crossed with each other, the offspring obtained are 3 black rabbits and 1 white. Determine the genotypes of parents and offspring.
- Guided by the law of character splitting, identify the genes that determine the manifestation of dominant and recessive characters in this cross. Black suit - A, white - a;
- Determine the genotypes of the parents (producing segregating offspring in a ratio of 3:1). Answer: Ah.
- Using the hypothesis of gamete purity and the mechanism of meiosis, write a crossing diagram and determine the genotypes of the offspring.
Answer: the genotype of a white rabbit is aa, the genotypes of black rabbits are 1 AA, 2Aa.
Other genetic problems are solved in the same sequence, using appropriate patterns.