A message on the topic of diversity. Variety of fruits. Diversity of plant organisms

Variety of animals. The animal kingdom includes more than 1.5 million species (the most numerous among other kingdoms of living organisms). Animals, like plants, bacteria, fungi, inhabit all living environments: aquatic - fish, whales, crayfish, jellyfish; ground-air - beetles, butterflies, birds, animals; soil - earthworms, mole crickets, moles. The habitat for many animals is other animals, humans, and plants.

Animals are diverse in size, body shape, integument, organs of locomotion, internal structure, behavior and other characteristics (compare, for example, jellyfish, earthworm, octopus, crayfish, cockchafer, shark, pigeon, wolf).

Similarities between animals and other organisms and their differences. Animals, like all other living organisms, have a cellular structure, eat, breathe, grow and develop, reproduce, and die. Unlike other organisms, they typically feed on solid food containing ready-made organic matter, and they have developed various adaptations for capturing, retaining, grinding and digesting it. Almost all animals have locomotion organs (fins, flippers, legs, wings) that facilitate active search for food, shelter from enemies and bad weather, etc. Most animals have noticeable differences in the front and rear ends of the body, the abdominal and dorsal sides, the left and right sides of the body . At the anterior (progressive) end of the body there is a mouth, the main sensory organs (vision, hearing, smell, taste, touch), organs of defense or attack. Mentally, only one plane can be drawn through the body of such animals, dividing it into two mirror-like identical halves. This symmetry of the body is called bilateral, or two-sided. It allows animals to move in a straight line, maintaining balance, and turn right and left with equal ease.

Along the body of some animals, such as jellyfish, you can draw several imaginary planes, and each of them will divide it into two mirror-like halves. The lines of the planes diverge from the center of intersection of the rays. This symmetry of the body is called radial. It is characteristic of animals that lead a mainly sedentary or sedentary lifestyle, and makes it possible to catch prey and sense the approach of danger from any direction.

Zoology - the science of animals

Zoology is the science of animals. People have been using animals in their lives for a long time. By hunting for animals, protecting their homes from predators and poisonous snakes, etc., they acquired knowledge about their appearance, habitat, lifestyle, habits and passed it on from generation to generation. Over time, books about animals appeared, and the science of zoology arose (from the Greek “zo-on” - animal and “logos” - word, doctrine). Her birth dates back to the 3rd century. BC. and is associated with the name of the ancient Greek scientist Aristotle.

Modern zoology is a whole system of animal sciences. Some of them study the structure, development of animals, lifestyle, distribution on Earth; others are specific groups of animals, for example only fish (ichthyology) or only insects (entomology). The knowledge gained by zoological sciences is of great importance for the protection and restoration of the numbers of a number of animals, the fight against plant pests, carriers and pathogens of human and animal diseases, etc.

Classification of animals. All animals, like other living organisms, are united by scientists into systematic groups based on signs of kinship. The smallest of them is the species. All white hares living in the taiga, mixed forests or tundra belong to one species - the white hare. In zoology, a species is a collection of animals that are similar to each other in all essential features of structure and vital activity, live in a certain territory and are capable of producing fertile offspring. Each animal that has unique structural and behavioral features is called an individual. Similar species are grouped into genera, genera into families, and families into orders. Larger systematic groups of animals - classes, types.

The animal kingdom includes two subkingdoms: Unicellular animals and Multicellular animals, which unite more than 20 types and several hundred classes.

Subkingdom single-celled animals, or protozoa

Single-celled animals live in bodies of water, dew drops on plant leaves, in moist soil, in the organs of plants, animals and humans.

The body of the protozoa consists of cytoplasm, on top of which there is a thin outer membrane, and in most, a dense shell. The cytoplasm contains a nucleus (one, two or more), digestive and contractile (one, two or more) vacuoles. Most protozoa actively move with the help of special organelles.

The subkingdom of protozoa includes 40 thousand species, combined into several types. The largest of them are two: the Sarcodaceae and Flagellates type and the Ciliates type.

Phylum sarcodaceae and flagellates

Sarcodidae and flagellates are mainly free-living organisms. The most common of them are amoeba vulgaris and green euglena. The common amoeba lives in the bottom areas of fresh water bodies. It does not have a constant body shape and moves by flowing into the resulting protrusions - pseudopods (in Greek, “amoeba” means “changeable”). Green Euglena lives in the upper layers of fresh water bodies. It has a dense shell, giving it a permanent spindle-shaped body shape; moves with the help of a flagellum. Inside the body of the euglena there is a nucleus, chloroplasts, a contractile vacuole, and a photosensitive eye.

Amoebas and other protozoa that do not have a shell and are capable of forming pseudopods are classified as sarcodes (from the Greek “sarcos” - plasma). Euglena and other protozoa that have flagella are classified as flagellates. Some flagellates, for example the flagellated amoeba, have flagella and pseudopods, which indicates a close relationship between sarcodidae and flagellates and serves as the basis for combining them into one type.

Nutrition. The common amoeba feeds mainly on unicellular organisms, capturing them with pseudopods. Food is digested in digestive vacuoles under the influence of digestive juice. At the same time, complex organic substances of food are transformed into less complex ones and pass into the cytoplasm (they are used to form their own organic substances, which serve as building materials and a source of energy). Undigested food remains are excreted in any part of the body. Euglena green, like unicellular algae, forms organic substances in the light. When there is a lack of light, it feeds on organic substances dissolved in water.

Breath. Free-living protozoa breathe oxygen dissolved in water, absorbing it over the entire surface of the body. Once in the cytoplasm, oxygen oxidizes complex organic substances, turning them into water, carbon dioxide and some other compounds. At the same time, the energy necessary for the functioning of the body is released. Carbon dioxide produced during respiration is removed through the surface of the body.

Irritability. Single-celled animals respond to light, temperature, various substances and other stimuli. The common amoeba, for example, moves from the light to a shaded place (negative reaction to light), and green euglena swims towards the light (positive reaction to light). The ability of organisms to respond to stimuli is called irritability. Thanks to this property, single-celled animals avoid unfavorable conditions and find food.

Reproduction of sarcodae and flagellates occurs by fission. The mother gives rise to two daughters, which, under favorable living conditions, grow quickly, and within a day they divide.

Preservation under unfavorable living conditions. When the water temperature drops or the reservoir dries out, a dense shell is formed from cytoplasmic substances on the surface of the amoeba’s body. The body itself becomes rounded, and the animal enters a resting state called a cyst (from the Greek “cystis” - bubble). In this state, amoebas not only survive under unfavorable living conditions, but also disperse with the help of wind and animals. Many sarcodaceae and flagellates turn into cysts, including amoeba dysenteria, Euglena green, Giardia and trypanosomes.

Type of ciliate

Habitats, structure and lifestyle.

The type of ciliates includes slippers, bursaria, geese, and souvoiki. These and most other ciliates live in fresh water bodies with decaying organic residues (their name comes from the Greek “infusion” - infusion). Their body shape is fusiform (slippers), barrel-shaped (bursaria), bell-shaped (trumpets).

The body of ciliates is covered with rows of cilia, with the help of which they move. There are ciliates, for example, suvoikas, which lead a sedentary lifestyle. They are attached to underwater objects by a contractile stalk.

Ciliates have a more complex structure compared to other protozoa. They have a large and small (or small) nuclei, a cellular mouth and pharynx, a perioral cavity, and a permanent place for removing the remains of undigested food - powder. Contractile vacuoles of ciliates consist of vacuoles themselves and afferent tubules.

Nutrition. Most ciliates feed on various organic debris, bacteria and unicellular algae. Food enters the preoral cavity due to the coordinated vibration of the surrounding cilia, and then through the mouth and pharynx into the cytoplasm (into the resulting digestive vacuole). Undigested food remains are removed through powder.

Respiration and excretion in ciliates occur in the same way as in sarcodidae and flagellates, across the entire surface of the body.

Irritability. In response to the action of light, temperature and other stimuli, ciliates move towards them or in the opposite direction (positive and negative taxis - movements).

Reproduction and preservation under unfavorable conditions in ciliates occur essentially in the same way as in sarcodidae and flagellates.

Origin and meaning of protozoa

Origin of protozoa. Scientists believe that sarcodaceae and flagellates are the most ancient protozoa. They evolved from ancient flagellates about 1.5 billion years ago. Ciliates - more highly organized animals - appeared later. The existence of flagellates that have chloroplasts indicates the relationship and common origin of protozoa and unicellular algae from the most ancient flagellates.

Coelenterates include jellyfish, sea anemones, and coral polyps. Their body consists of two layers of cells, between which there is a non-cellular supporting plate. The cells limit the cavity, which communicates with the external environment with one opening - the mouth. Partial digestion of food occurs in it. Coelenterates are lower multicellular animals with radial symmetry of the body.

Some of the coelenterates lead a sedentary lifestyle, attaching to the substrate. They are called polyps (from the Greek “polyp” - many-legged). Others - jellyfish - swim freely in the water column. About 9 thousand species of this type have been described. Main classes: Hydroid, Scyphoid and Coral polyps.

Hydroid class

Hydroids include freshwater hydras (brown, stalked, green, etc.) and marine colonial polyps, such as obelia. Freshwater hydras look like plant stems 1-3 cm long. At one end of their body there is a sole with which they are attached to the support, at the other there is a mouth surrounded by tentacles. Hydras lead a solitary, predominantly attached lifestyle. By their feeding method they are predators. Their main food is daphnia and cyclops. Marine hydroids lead a sedentary lifestyle and look like small bushes consisting of several hundred and even thousands of individuals.

The outer layer of the hydroid body consists of integumentary-muscular, stinging, intermediate and some other types of cells. Integumentary muscle cells with muscle fibers contract and relax the tentacles and the entire body. Stinging cells are located mainly on the tentacles. The poisonous liquid contained in their capsules paralyzes or kills small animals, and causes a burning sensation in large ones. Intermediate cells give rise to cells of other species.

The inner layer of the body is formed by glandular and digestive muscle cells. Glandular cells secrete digestive juice into the intestinal cavity. Under its influence, food is partially digested. Digestive muscle cells move food particles in the intestinal cavity with flagella, and with pseudopods they capture them and digest them in digestive vacuoles. Thus, in coelenterates both intracavitary and intracellular digestion occur. Nutrients are supplied to all cells of the body, and undigested food remains are eliminated through the mouth. Respiration and excretion in coelenterates occur through the entire surface of the body.

Nervous network. Reflex. On both sides of the supporting plate are nerve cells that form the nerve network. When any animal touches a hydra or an obelia specimen, an excitation occurs in the sensitive cells, which is transmitted to the nerve cells, spreads throughout the nervous network and causes contraction of the skin-muscle cells. The body's response to the action of stimuli, carried out through the nervous network (nervous system), is called a reflex.

Reproduction. Under favorable living conditions, buds form on the body of hydras. They increase in size, tentacles and a mouth are formed at their free end, and then a sole. In single polyps, daughter individuals separate from the mother’s body and live independently; in colonial polyps, they do not separate and colonies grow. Budding is an asexual method of reproduction.

Sexual reproduction of hydras is associated with the formation of special tubercles. In bisexual hydras (hermaphrodites), eggs develop in some tubercles of the body, and sperm in others; in heterosexuals - either eggs or sperm. Mature sperm enter the water, penetrate the tubercles of other individuals and merge with the eggs. Multicellular embryos are formed in fertilized eggs. They overwinter and the adults die. In spring, embryo development resumes and young hydras appear.

The marine colonial hydroid obelia has individuals without tentacles or a mouth. At certain times of the year they bud small jellyfish (bell diameter 2-3 mm), which differ in gender. Female jellyfish release eggs into the water, and males release sperm. From fertilized eggs, larvae develop with cilia, which attach to underwater objects and give rise to new colonies of polyps.

Regeneration. Many coelenterates are characterized by regeneration - the ability to restore damaged and lost body parts. An entire hydra, for example, can develop from 1/200 of its body.



Fish, crayfish, whales, jellyfish, animals and live on the ground and in the air, and earthworms, moles and mole crickets live in the soil. The habitat for some animals is other living organisms and plants.

photo: Bill Gracey

The fauna of our planet is represented by unique organisms: from single-celled crumbs that can only be seen with a microscope, to giant whales whose mass reaches 150 tons. Thanks to constant evolution, animal organisms are endowed with unique properties: they move, feed, protect themselves from enemies, reproduce and raise offspring in various conditions.

Animal classification

In the animal kingdom the following taxa are distinguished:

Family;

Species are united into a genus, families into a series, classes into a phylum. In addition to these taxa, intermediate concepts are used: subtypes, subclasses and others. All living organisms are divided into:

Protozoa;

Insects;

Amphibians;

Reptiles;

Mammals.

photo: David Shannon

Meaning of Animals

Representatives of the animal world are of great importance for the entire planet: they participate in the cycle of substances in nature, pollinate plants, and distribute fruits and seeds. They act as natural orderlies; in addition, they regulate the number of herbivorous organisms. : Animals are farmed and harvested for meat, hides, fur, milk and eggs; animals are used for research, medical and scientific purposes. The effects of certain medications are studied on laboratory mice, hamsters, rats and guinea pigs; monkeys are used in experiments with table cells. Bee and snake venom are used for medicinal purposes.

photo: Rob Escott

Peculiarities of animal settlement

The population density of representatives of the animal world is influenced by various factors. These include climate, terrain, human activities and relationships between different species. Adaptation to environmental conditions is expressed in the characteristics of living organisms. Thus, in order to find favorable conditions for living, feeding and reproduction, many organisms travel vast distances. These movements are called migrations. As an example, we can give the following example: fish of the salmon order grow in the sea and reproduce in the upper reaches of rivers. The fry of these fish hatched from eggs are carried back to the sea by the river current, where they continue to grow.

photo: Jiya Aggarwal

If you move from the poles to the equator, it becomes noticeable that the number of species of living organisms increases. The biggest one is . For example, there are more than 40 species of parrots alone, and thousands of species of butterflies.

Evolution of Biodiversity

In the history of the animal world, there have always been periods of decline and increase in biodiversity. They are characterized by the emergence of new species that replaced others. Scientists learn about these stages from archaeological excavations: fossils and impressions. Thus, in the Precambrian, 670 million years BC, soft-bodied invertebrate animals, annelids and coelenterates dominated. The Cambrian and Silurian, 590-438 million years BC, were characterized by shelled marine invertebrates, insects reigned during the Late Carboniferous and Cenozoic, amphibians dominated the Carboniferous and Triassic, reptiles were most abundant in the Permian and Cretaceous, and mammals reached their peak in the Cenozoic.

The flourishing and decline of species is a natural process that occurs under the influence of climate change in individual regions and on the entire planet as a whole. Scientists assume that most species of living organisms will become extinct sooner or later. Some will transform into more evolutionarily advanced species, but others will not be able to adapt to new environmental conditions. The latter are threatened with extinction.

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>>Plant diversity

§ 5. Plant diversity

Plants differ from each other in color and shape of stems, leaves, flowers and fruits, life expectancy and other features.

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Abstract: Biodiversity

1. Introduction

2) Types of diversity

Species diversity

Genetic diversity

3) Key species and resources

4) Measuring biodiversity

5) Optimal and critical levels of diversity

6) What kind of biodiversity is there?

7) Types of extinction

8) Goals of biodiversity management at the present stage

9) Ethical arguments for biodiversity conservation

10) Conclusion

11) List of references used

MINISTRY OF EDUCATION OF THE RUSSIAN FEDERATION

ROSTOV STATE UNIVERSITY

PSYCHOLOGY FACULTY

ABSTRACT

at the rate:

"Concepts of Modern Natural Science"

"The role of biodiversity in wildlife"

Performed:

4th year student, 1st group

day department

Faculty of Psychology

Bronevich Marina

Rostov-on-Don

According to the definition given by the World Wildlife Fund (1989), biological

diversity is “the entire diversity of life forms on earth, millions of species

plants, animals, microorganisms with their sets of genes and complex ecosystems,

forming living nature.” Thus, biological diversity should

considered at three levels. Biological diversity at the species level

covers the entire range of species on Earth from bacteria and protozoa to the kingdom

multicellular plants, animals and fungi. On a smaller scale

biological diversity includes the genetic diversity of species,

formed both by geographically distant populations and by individuals within

the same population. Biological diversity also includes

diversity of biological communities, species, ecosystems formed

communities and interactions between these levels (Fig. 1).

Rice. 1 Biological diversity includes genetic diversity

(hereditary variability within each species), species diversity (set

species in a given ecosystem) and diversity of communities/ecosystems (habitats and

ecosystems in a given area)

All levels are necessary for the continued survival of species and natural communities.

biological diversity, all of which are important for humans. Variety of species

demonstrates the richness of evolutionary and ecological adaptations of species to

various environments. Species diversity serves as a source for humans

variety of natural resources. For example, tropical rainforests with their

rich variety of species produce a remarkable diversity of plant and

animal products that can be used for food, construction and

medicine. Genetic diversity is necessary for any species to survive

reproductive viability, disease resistance, ability to

adaptation in changing conditions. Genetic diversity of domestic animals

animals and cultivated plants are especially valuable for those who work on

breeding programs to maintain and improve modern

agricultural species.

Community-level diversity represents the collective response of species

to various environmental conditions. Biological communities characteristic

for deserts, steppes, forests and flooded lands, maintain continuity

normal functioning of the ecosystem, providing its “service”,

for example, through flood control, protection against soil erosion,

air and water filtration.

2. Species diversity

At each level of biological diversity - species, genetic and

diversity of communities, experts study the mechanisms that change or

maintain diversity. Species diversity includes the entire range of species

living on Earth. There are two main definitions of the concept of species. First:

a species is a collection of individuals that, for one reason or another,

differs in morphological, physiological or biochemical characteristics

from other groups. This is the morphological definition of the species. Now to differentiate

species that are almost identical in appearance (for example, bacteria) are increasingly

use differences in DNA sequence and other molecular markers.

The second definition of a species is a collection of individuals between which there is

free crossing, but there is no crossing with individuals of other

groups (biological definition of species).

3. Genetic diversity

Genetic diversity within species is often provided by reproductive

behavior of individuals within a population. A population is a group of individuals of the same

species that exchange genetic information among themselves and produce fertile

offspring. A species may contain one or more distinct populations. Population

can consist of several individuals or millions.

Individuals within a population are usually genetically different from each other.

Genetic diversity is due to the fact that individuals have slightly

differing genes - sections of chromosomes that encode certain

proteins. Variants of a gene are known as its alleles. Differences arise from mutations

– changes in the DNA that is found in the chromosomes of a particular individual. Alleles

genes can have different effects on the development and physiology of an individual. Breeders

varieties of plants and animal breeds, selecting certain gene variants,

create high-yielding, pest-resistant species, such as cereals

crops (wheat, corn), livestock and poultry.

4. Diversity of communities and ecosystems

A biological community is defined as a collection of individuals of different

species living in a certain territory and interacting with each other.

Examples of communities are coniferous forests, tallgrass prairies, tropical rainforests

forests, coral reefs, deserts. The biological community together with

its habitat is called an ecosystem. In terrestrial ecosystems, water

evaporated by biological objects from the surface of the Earth and from water

surfaces to fall again as rain or snow and replenish

terrestrial and aquatic environments. Photosynthetic organisms absorb light energy

which is used by plants for their growth. This energy is absorbed

animals that eat photosynthetic organisms or is released as

heat both during the life of organisms and after their death and

decomposition.

During photosynthesis, plant organisms absorb carbon dioxide and

produce oxygen, and animals and fungi absorb oxygen during respiration and

release carbon dioxide. Mineral nutrients such as nitrogen and

phosphorus, circulate between living and nonliving components of the ecosystem.

Physical properties of the environment, especially the annual temperature regime and

precipitation, affect the structure and characteristics of the biological community and

determine the formation of either a forest, or a meadow, or a desert or swamp.

The biological community, in turn, can also change physical

characteristics of the environment. In terrestrial ecosystems, for example, wind speed,

humidity, temperature and soil characteristics can be determined

influence of the plants and animals living there. In aquatic ecosystems such

physical characteristics such as turbulence and transparency of water, its

chemical characteristics and depth determine qualitative and quantitative

composition of aquatic communities; and communities such as coral reefs are themselves

significantly influence the physical properties of the environment. Inside

biological community, each species uses a unique set of resources,

which constitutes his niche. Any niche component can become limiting

factor when it limits population size. For example, populations of species

bats with highly specialized requirements for environmental conditions,

forming colonies only in calcareous caves, may be limited

number of caves with suitable conditions.

The composition of communities is largely determined by competition and predators. Predators

often significantly reduce the number of species - their prey - and may even

displace some of them from their usual habitats. When predators

are exterminated, the population size of their victims may increase to critical

level or even go beyond it. Then after exhaustion of the limiting resource

population destruction may begin.

5. Key species and resources

Certain species within biological communities can play such

important role that determines the ability of other species to persist in

community. Such key species1 influence the organization of the community to a much greater extent.

to a greater extent than would be predicted based on their numbers

or biomass. Protection of key species is a priority for

environmental protection measures, since following their disappearance in

Many other species may also disappear from a protected area (Fig. 2).

Large predators such as wolves are among the most obvious key

species because they regulate herbivore populations. At

In the absence of wolves, the population density of deer and other herbivores may

increase so much that it will lead to the grazing and destruction of plant

cover, and consequently, to the extinction of species associated with it

insects and soil erosion.

In tropical forests, ficus trees are considered key species providing

populations of many birds and mammals with their fruits at a time when others

their preferred types of feed are missing. Beavers are also among the key

species, since through their dams they create wet habitats,

examples of other key species. They determine the population density of their

"owners".

The extinction of a single keystone species, even one that constitutes

an insignificant part of the community biomass, can provoke a series

linked extinctions of other species, known as the extinction cascade.

As a result, a degraded ecosystem appears with a much lower

biological diversity at all trophic levels. Return

key species into the community will not necessarily restore the latter to the original

state, if by this time its other members have disappeared and the

environmental components (for example, soil).

6. Measuring biodiversity

In addition to the definition of biological that is closest to most biologists

diversity, as the number of species living in a certain area,

There are many other definitions related to the diversity of biological

communities at different hierarchical levels of their organization and in different

geographical scale. These definitions are used to test theories about

that increased diversity at different levels leads to increased

stability, productivity and resistance of communities to invasion of alien

species. The number of species in a particular community is usually described as richness

species or alpha diversity and is used to compare biodiversity in

different geographic regions or biological communities.

The term “beta diversity” expresses the degree of change in species composition across

geographic gradient. Beta diversity is high if, for example, a species

the composition of moss communities differs significantly in alpine meadows of adjacent

peaks, but beta diversity is low if most of the same species occupy

the entire belt of alpine meadows.

Gamma diversity is applicable over large geographic scales; it

takes into account the number of species over a large area or continent.

The three types of diversity can be illustrated by a theoretical example of three

alpine meadows (Fig. 3).

Rice. 3. Biodiversity indicators for three regions, with three mountain peaks

in everyone. Each letter represents a population of a species. Some types

are found only on one mountain, while others are found on two or three. For each

region shows alpha, beta and gamma diversity. If there are enough funds for

protection of only one mountain range, region 2 should be selected, since here

greatest overall diversity. However, if it is possible to protect only one mountain,

then it should be selected in region 1, since this is the highest local

alpha diversity, i.e. the highest average number of species per peak. Every peak

in region 3 has a more limited range of species than the mountains in the other two

regions, which shows its high beta diversity rates. Generally

Region 3 has a lower priority for protection.

7. Optimal and critical levels of diversity

Diversity can be considered as the most important parameter of biosystems, associated

with their vital characteristics, which are criteria for effectiveness

and extremized in the course of their development (stability, production of entropy and

etc.). Extreme (maximum or minimum) criterion value

efficiency of the biosystem G*(Fig.) is achieved at an optimal level

diversity D*. In other words, the biosystem achieves its goal when

optimal level of variety. Decrease or increase in diversity by

compared to its optimal value leads to a decrease in efficiency,

stability or other vital characteristics of the biosystem.

Critical or acceptable levels of diversity are determined by the same

the relationship between the criterion of system efficiency and its diversity.

Obviously, there are values ​​of the efficiency criterion at which

the system ceases to exist, for example, minimum stability values

or the energy efficiency of the Go system. These critical values

correspond to the levels of system diversity (Do), which are the maximum

acceptable, or critical, levels.

Possibility of existence of optimal diversity values ​​in biosystems

population and biocenotic levels is shown on empirical data and

Biodiversity modeling results. Concept of critical

levels of diversity - today one of the theoretical principles for the protection of living

nature (concepts of minimum population size, critical levels

genetic diversity in populations, minimum ecosystem area and

8. What kind of biological diversity is there?

The richest species are tropical rainforests, coral reefs, extensive

tropical lakes and deep seas. There is great biological diversity and

dry tropical areas with their deciduous forests, scrub bushes,

savannas, prairies and deserts. In temperate latitudes, high rates

shrub-covered areas with a Mediterranean type stand out

climate. They are found in South Africa, southern California and the southwest

Australia. Tropical rainforests are primarily characterized by

exceptional variety of insects. On coral reefs and deep sea

in the seas, diversity is due to a much wider range of systematic

groups. The diversity in the seas is associated with their great age, gigantic

areas and stability of this environment, as well as the uniqueness of the types of bottom

sediments. Remarkable diversity of fish in large tropical lakes and

the appearance of unique species on the islands is due to evolutionary radiation in

isolated productive habitats.

The species diversity of almost all groups of organisms increases in direction

to the tropics. For example, Thailand is home to 251 species of mammals, and France

– only 93, despite the fact that the areas of both countries are approximately the same

(Table 1.2).

The contrast is especially noticeable in the case of trees and other flowering plants.

plants: 10 hectares of forest in the Peruvian Amazon can grow 300 and

more species of trees, while the same area of ​​forest in temperate

climatic zone of Europe or the USA can be formed by 30 or fewer species.

The diversity of marine species also increases towards the tropics.

For example, the Great Barrier Reef in Australia is formed by 50 genera of corals in

its northern part, located near the Equator, and only 10 genera in more

distant southern part.

Tropical forests have the greatest diversity of species. Although these forests

cover only 7% of the Earth's surface, more than half of the species live in them

planets. These estimates are based primarily on counts of insects and other

arthropods, i.e. groups that account for the majority of species in the world.

The number of as yet unidentified insect species in tropical forests is believed to be

ranges from 5 to 30 million.

The state of species richness also depends on local topographic features,

climate, environment and geological age of the area. In terrestrial communities

species richness usually increases with decreasing altitude, increasing

solar radiation and increased precipitation. Species richness is usually

higher in areas with complex terrain, which can provide genetic

isolation and, accordingly, local adaptation and specialization. For example,

a sedentary species that lives on isolated mountain peaks may, over time,

evolve into several different species, each adapted to

certain mountain conditions. In areas that differ

high geological complexity, a variety of clearly limited

soil conditions, various communities are formed accordingly,

adapted to a particular type of soil. Large in the temperate zone

floristic richness is typical for the southwestern part of Australia, South

Africa and other areas with a Mediterranean type of climate with its mild,

wet winters and hot dry summers. Species richness of shrub communities and

herbs is caused here by a combination of significant geological age and

difficult terrain. The open ocean has the greatest species richness

is formed where different currents meet, but the boundaries of these areas,

usually unstable over time

Rice. 4. The number of described species is indicated by the shaded parts of the bars;

traditional estimates of the actual number of extant species for these groups

organisms suggest that it should be increased by 100,000 species, they are shown

in the shaded column on the right (vertebrates included for comparison). Number

unidentified species are especially unclear for different groups of microorganisms.

The total number of existing species, according to some estimates, can reach 5–10 million,

or even 30–150 million.

These little-studied groups can number hundreds and thousands, even millions

species. Until now, along with individual species, completely

new biological communities, especially in extremely remote or

places difficult to reach for humans. Special study methods allowed

identify such unusual communities, primarily in the deep seas and in

forest canopy:

Diverse animal communities, primarily insects,

adapted for life in the crowns of tropical trees; they are practically not

have no connection with the earth. To penetrate the forest canopy, in recent years

scientists install observation towers in forests and stretch suspended

paths.

At the bottom of the deep seas, which remain poorly studied due to

for technical difficulties in transporting equipment and people in conditions

high water pressure, there are unique communities of bacteria and animals,

formed near deep-sea geothermal springs. Previously

unknown active bacteria were found even in a five-hundred-meter layer of sea

sediments, where they undoubtedly play an important chemical and energetic role

in this complex ecosystem.

Thanks to modern drilling projects under the Earth's surface, down to

depths up to 2.8 km, various bacterial communities were found, with a density

up to 100 million bacteria per g of rock. The chemical activity of these communities is active

is being studied in connection with the search for new compounds that could potentially

be used to break down toxic substances as well as respond to

question about the possibility of life existing on other planets.

9. Types of extinction

Since the origin of life, species diversity on Earth has gradually

increased. This increase was not uniform. It was accompanied

periods with high rates of speciation, which were replaced by

periods with a low rate of change and were interrupted by five outbreaks of massive

extinctions. The most massive extinction occurred at the end of the Permian period,

250 million years ago, when it is estimated that 77–96% of all species became extinct

marine animals (Fig. 1.7).

It is likely that some kind of mass disturbance, for example, widespread

a volcanic eruption or a collision with an asteroid caused such dramatic

changes in the Earth's climate that many species could no longer exist in

current conditions. The evolutionary process took about 50 million years,

to restore the diversity of families lost during the massacre

Permian extinction. However, species extinctions also occur in the absence of powerful

destructive factors. One species may be replaced by another or be

destroyed by predators. Species in response to changing environmental conditions or due to

spontaneous changes in the gene pool may not die out, but gradually

evolve into others. Factors that determine resilience or vulnerability

specific species are not always clear, but extinction is just as natural

process, like speciation. But if extinction is natural, why

so much talk about species loss? The answer lies in relative speeds

extinction and speciation. Speciation is generally a slow process,

going through the gradual accumulation of mutations and shifts in allele frequencies in

for thousands, if not millions of years. As long as the rate of speciation

equal to or greater than extinction rates, biodiversity will remain either

same level or increase. In past geological periods, extinction

species was balanced or increased due to the formation of new species.

However, current extinction rates are 100–1000 times higher than those

previous eras. This modern extinction surge, sometimes called

sixth extinction, caused largely solely by activity

person. This species loss is unprecedented, unique and irreversible.

character.

10. Goals of biodiversity management at the present stage

Formulation of goals for biodiversity management at the present stage

necessary to develop a sufficiently complete and internally consistent

systems of criteria for determining the environmental status of natural systems.

Some options for formulating biodiversity management objectives are shown

Options for formulating goals	Required knowledge
Minimizing changes to currently existing levels of biodiversity (for disturbed systems means preserving them in their current state)	The relative importance of different biological systems for the conservation of biodiversity as a whole
Preservation or restoration of “natural” levels of biodiversity characteristic of undisturbed natural systems (specially protected natural areas play a huge role as standards of systems)	Characteristics of biodiversity of undisturbed natural systems
Maintaining or restoring levels of diversity above critical levels necessary for the conservation of biological systems	Critical Biodiversity Values
Maintain or restore optimal levels of biodiversity	Optimal diversity values

The last two options for formulating goals involve solving the problem on

theoretical level, revealing the connection between biodiversity parameters and

functional characteristics of biosystems, determination of optimal and

critical values ​​of diversity in biosystems. This requires serious

additional research, but provides an opportunity for objective

setting priorities. Since today our knowledge of critical and

optimal levels of diversity in biosystems are extremely scarce, it should be

recognize that such management goals can only be set in very

limited number of cases. The first two are more realistic at the present stage

options for formulating goals based only on measuring levels

diversity in biosystems. In this case, the lack of quantitative criteria

to establish conservation priorities between different biosystems

involves the use of an expert assessment method.

Several ethical arguments can be made in defense of conservation.

of all types, regardless of their economic value. Subsequent considerations

important to conservation biology because they provide logical arguments in

protection of rare species and species of no apparent economic value.

Every species has the right to exist. All types represent

a unique biological solution to the problem of survival. On this basis

the existence of each species must be guaranteed, regardless of

distribution of this species and its value to humanity. It doesn't depend on

the number of species, on its geographical distribution, whether it is ancient or

a recently emerged species, whether economically significant or not. All types are

part of existence and therefore have as many rights to life as a person.

Each species is valuable in itself, regardless of human needs. Besides,

that people do not have the right to destroy species, they must also bear responsibility

for taking measures to prevent species extinction as a result of human

activities. This argument anticipates that man will rise above

limited anthropocentric perspective, will become part of life and

identify with a larger community of life in which we respect all

species and their right to exist.

How can species be given the right to exist and protected by law?

deprived of human consciousness and the concept of morality, law and duty? Next, how

may species of non-animal origin, such as mosses or fungi, have rights,

when they don't even have a nervous system to properly

perceive the environment? Many environmental ethicists

believe that species have a right to life because they produce offspring

and continuously adapt to a changing environment. Premature

extinction of species as a result of human activity destroys this

a natural process and can be considered “super-murder” because

it kills not only individual representatives, but also future generations of species,

limiting the process of evolution and speciation.

All species are interdependent. Species as parts of natural communities

interact in complex ways. The loss of one species can have far-reaching consequences

implications for other community species. As a result, others may become extinct

species, and the entire community is destabilized by the extinction of groups of species.

The Gaia hypothesis is that as we learn more about

global processes, we are increasingly discovering that many chemical and

physical parameters of the atmosphere, climate and ocean are related to biological

processes based on self-regulation. If this is the case, then our

self-preservation instincts should push us to preserve biodiversity.

When the world around us prospers, we prosper too. We are obliged to preserve

the system as a whole, since it survives only as a whole. People are so thrifty

the owners are responsible for the Earth. Many followers of religious beliefs

consider the destruction of species unacceptable, since they are all creations of God. If

God created the world, then the species created by God have value. In accordance with

traditions of Judaism, Christianity and Islam, human responsibility for

The protection of animal and plant species is, as it were, an article of agreement with God.

Hinduism and Buddhism also strictly require the preservation of life in the natural environment.

People have a responsibility to future generations. Strictly

ethical point of view, if we deplete the earth's natural resources and become

cause the extinction of species, then future generations of people will have to pay for it

pay the price of a lower standard and quality of life. Therefore modern

humanity must use natural resources in a conservation mode, not

allowing the destruction of species and communities. We can imagine that

we borrow the Earth from future generations, and when they get it back from us, then

they should find it in good condition.

The relationship between human interests and biological diversity. Sometimes

believe that concern for nature protection frees us from the need to care about

human life, but this is not so. Understanding the complexity of human culture and

natural world forces man to respect and protect all life in its

numerous forms. It is also true that people will probably be better able

protect biological diversity when they have full

political rights, secure livelihoods and knowledge about

environmental problems. The struggle for social and political progress

of a poor and disenfranchised people is comparable in effort to protecting the environment. On

over a long period of human development, he followed natural

ways of “identifying all forms of life” and “understanding the value of these forms.” In that

there seems to be an expansion of the range of moral obligations of an individual:

extending his personal responsibility to relatives, to his social

group, to all humanity, animals, all species, ecosystems and ultimately

to the whole Earth

Nature has its own spiritual and aesthetic value that surpasses it

economic value. Throughout history it has been noted that

religious thinkers, poets, writers, artists and musicians drew

inspiration in nature. For many people, an important source of inspiration was

admiring the pristine wild nature. Simply reading about species or observing in

museums, gardens, zoos, films about nature - all this is not enough. Almost

everyone gets aesthetic pleasure from wild nature and landscapes. From

Millions of people enjoy active communication with nature. A loss

biodiversity reduces such enjoyment. For example, if in the next

In a few decades, many whales, wild flowers and butterflies will become extinct, then future

generations of artists and children will forever be deprived of enchanting living paintings.

Biodiversity is essential to determining the origin of life.

There are three main mysteries in world science: how life originated, where

where all the diversity of life on Earth came from and how humanity evolves.

Thousands of biologists are working to solve these problems and are unlikely to come closer to them.

understanding. For example, recently taxonomies using molecular techniques

discovered that a bush from the island of New Caledonia in the Pacific Ocean represents

the only surviving species of an ancient genus of flowering plants. However, when

such species disappear, important keys to solving major mysteries are lost, and the mystery

is becoming increasingly intractable. If your immediate family disappears

humans - chimpanzees, baboons, gorillas and orangutans - we will lose important keys

to understanding human evolution

Conclusion:

People at all levels of human society must be aware that

amid the ongoing loss of species and biological communities in the world in their

In our own interests, we must work to preserve the environment. If

environmentalists will be able to convince that the conservation of biodiversity is more valuable than anything else

its violations, then the peoples and their governments will begin to take

positive action.

Bibliography:

· R. Primak. Fundamentals of biodiversity conservation / Trans. from English O.S.

Yakimenko, O.A. Zinovieva. M.: Publishing house of Scientific and educational methodological

Center, 2002. 256 p.

· Conservation and restoration of biodiversity. Coll. authors. M.:

Publishing house of the Scientific and Educational Methodological Center, 2002. 286 p.

· Geography and monitoring of biodiversity.

· Socio-economic and legal basis for biodiversity conservation.

12) Introduction

13) Types of diversity

Species diversity

Genetic diversity

· Diversity of communities and ecosystems

14) Key species and resources

15) Measuring biodiversity

16) Optimal and critical levels of diversity

Biodiversity. Significant role soil cover in... two related concepts: concept biological productivity of soils... primarily on his multi-causality...

Concept land resources of Russia

Abstract >> Geography

Nature education. His role in the life of society... for thousands of years, the basis alive nature and agricultural production...an agricultural enterprise is usually distinguished concepts: - general land... unevenness of protection biodiversity. Almost all...

Concept sustainable development. State debt

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Conservation Factors biodiversity Astrakhan region in protected reserves

Thesis >> Ecology

2001). Very large role in the fate of the reserve... resources. 3.2. Definition concepts“biological diversity” Is... a fundamental property alive nature, reflecting a variety of... 5. Raising awareness of biodiversity And his security at local and...

Conservation measures biodiversity

Abstract >> Ecology

The source is still live nature. It is used in construction... river flow, stabilizes his and plays role a kind of “water buffer” ... – inclusion of terms and concepts related to biodiversity, in all relevant legislative...

Nematodes (lat. Nematoda, Nematodes) or roundworms are the second largest group of multicellular animals on Earth (after arthropods), distinguished by their appearance and structure. Formally, they belong to protocavitary worms, but this is an outdated classification.

Morphology

Nematodes are structurally simple organisms. Adult nematodes consist of approximately 1000 somatic cells, as well as hundreds of cells associated with the reproductive system. These roundworms have been characterized as having a "tube within a tube" based on a gastrointestinal tract that runs from the mouth at the front end to the anus located near the tail. Nematodes have digestive, nervous, excretory and reproductive systems, but do not have a dedicated circulatory or respiratory system. They range in size from 0.3 mm to more than 8 meters.

Reproduction

Most nematode species are dioecious with distinct male and female individuals. Although some, such as Caenorhabditis elegans, have androdiecy - they are represented by hermaphrodites and males. Both sexes have one or two tubular gonads (ovaries and testes, depending on gender).

Reproduction of nematodes is usually based on mating, although hermaphrodites are capable of self-fertilization. Males are usually smaller than females or hermaphrodites and often have a characteristic curved or fan-shaped tail for holding the opposite sex. During mating, one or more chitinous spicules emerge from the cloaca and are inserted into the female's genital opening. This is how the seminal fluid is transmitted, which during the process passes along the length of the entire male.

Due to the lack of knowledge about many nematodes, their taxonomy is controversial and has changed several times. In various sources you can find very different classifications. In most of them, according to outdated information, nematodes are distinguished as a class, although they are already classified as a separate type, including several classes. But there is still controversy about this.

Previously, this was a suborder, but is now separated as a separate detachment.

All of these suborders include several families, which, in turn, are divided into genera, and those into species.

Habitat

Roundworms can adapt to any ecosystem, so they can be found in fresh and salt water, soil, polar regions and the tropics. Nematodes are ubiquitous. Scientists have discovered worms in every part of the earth's lithosphere.

Human infection

Live roundworm in the human intestine during colonoscopy

Roundworms enter the body:

When nematodes infect a person, they experience the following symptoms:

1. Problems with stool.
2. Vomiting and nausea.
3. Lost appetite.
4. Dark circles under the eyes.
5. Itching in the anal area.

Subsequently, nematodes begin to penetrate many human organs and actively reproduce. As a result, a person begins to feel severe weakness, an allergic reaction may develop, in rare cases, mental disorders, etc. Nematodes in humans greatly reduce immunity.

Animal infection

A person can become infected with nematodes from cats, dogs and other animals if basic hygiene rules are not followed.

Nematode diseases in plants

Brown streaks on potato stems caused by Trichodoride nematodes.

The most famous types are:

Particular attention is paid to a highly specialized species of worms – the golden potato nematode (Globodera rostochiensis). Almost everyone who has grown plants of the nightshade family at home or in the country is familiar with it. They prefer to settle on the roots of potatoes and tomatoes. The individual develops in the rhizome. Cysts are spread by soil, wind, water and infected tubers. Therefore, when potato nematode is detected, the infested area is quarantined.

You should know that the golden potato nematode, like other similar plant pests, is absolutely safe for humans.

Free-living nematodes

In free-living species, development usually consists of four cuticle molts during growth. Different species of these nematodes feed on a wide variety of foods - algae, fungi, small animals, feces, dead organisms and living tissue. Free-living marine nematodes are important and abundant members of the meiobenthos (meiofauna, i.e. organisms living on the bottom). They play an important role in the decomposition process, help break down nutrients in the marine environment and are sensitive to changes due to pollution. Of note is the soil-dwelling roundworm Caenorhabditis elegans, which has become a model organism for scientists, i.e. used in various experiments. This is due to the fact that its genome (set of genes) has long been fully studied, and this makes it possible to observe changes in the body when manipulating genes.