The whole material world around us, called nature, consists of living and non-living organisms. Consider their coexistence. Non-living objects as a concept can be characterized on several levels: atoms, molecules, macrobodies, mega-objects, galaxies, clusters of galaxies and, finally, the Universe.
But what is the primary element? Modern science has determined that the smallest “brick” is a quark, from which atoms and other elementary particles are formed.
However, inanimate nature exists in two forms: matter and field (they both have energy). The energy of the substance reflects the brilliant formula of Einstein:
The substance is in four states: solid, liquid, gaseous and like plasma.
Living and nonliving organisms do not just interact. We discuss this. Initially, it was only inanimate: the Earth itself as a planet formed 4.5 billion years ago, and the countdown of the appearance of life on it began 0.5 billion years ago. As a result of the development of inanimate nature, living arose.
Since then, animate and inanimate nature does not just coexist - they interact closely with each other. Under the influence of living organisms in the Earth’s atmosphere, the specific gravity of oxygen increased and decreased - carbon dioxide. The relief has also changed thanks to mountains of organic origin. Microorganisms have determined the process of soil formation (modern soil suitable for agriculture is a product of their vital activity). Appeared oil deposits.
The full functioning of the biosphere is impossible without living organisms. They actively contribute to the universal circulation in nature. As you can see, the value of living organisms is enormous.
The emergence of life
How did life originate on earth? Initially, reserves of organic substances were created for her. Academician Alexander Ivanovich Oparin at the beginning of the last century experimentally proved the appearance of organic matter suitable for the “start of life” under the influence of electric charges in the inanimate nature. And in the middle of the same century, the American scientist Stanley Lloyd Miller (in fact, continuing the research of the Russian academician) synthesized nucleic acids - the basis of the structure of proteins. According to Oparin, coacervates — self-regulating structures with a fatty membrane — could become the prototype of the appearance of the simplest unicellular organisms.
According to the version accepted by many scientists, the first living organisms were brought to Earth from outside, by meteorites, 500 million years ago. The version is believable, especially since one of their classes - “carbonaceous chondrid” - really brings bacteria and microbes to the Earth. And the scientists of the Amudsen-Scott station managed to detect a probable "culprit" - a bacterium of the genus Deinococcus, capable of both "traveling" and "landing."
Animal world
But back to reality. Let's distract from the asphalt of megalopolises. As soon as we, city dwellers, go to nature, to the country, we almost everywhere - in water, on the ground and in the air, in the soil - meet a variety of living organisms.
Indeed, the animal world is omnipresent. The ground-air environment was inhabited by insects, spiders, animals, birds, reptiles, its population is most diverse. The aquatic habitat is quite dense, fluid and less saturated with oxygen, its creatures were divided into fast-swimming (nekton), with a limited habitat - bottom or near-surface (benthos), distributed throughout the water column (plankton). Soil is a dense environment with stable temperature conditions; light does not enter the underworld, where worms, insects, and larvae live. Mole rats and moles adapted to life in it. Parasitic animals (for example, worms) have adapted to life in the bodies of other creatures.
Classification
It is interesting that all this is moving, breathing, eating, growing, reproducing variety - it all comes down to certain classes of living organisms. How is it classified? A view is taken as a reference point. It is the basis (primary link) for the classification of living organisms. The largest number of them show insects. Every year, with enviable stability, science registers about 7 thousand of their species. The species has its own habitat. The individuals that form it are similar in structure and interbreed. Their offspring are capable of breeding. Species of living organisms do not spread evenly over their range, but populations, each of which has its own territory.
Similar species are combined into a genus. For example, wolves include wolves, coyotes, jackals, dogs, dingoes. Similar genera come together in families. The Canine family united the genus of wolves, foxes, arctic foxes, raccoon dogs, the genus of hyenoid dogs. Close families, in turn, are united in a detachment. So, the Canidae, Viverra, Feline, Hyena, Bear, Raccoon, Kunya families comprise the Predatory detachment. Classes of living organisms unite their units. The Mammals order, in particular, presents 25 orders, let's name some of them: Predators, Rodents, Batwing, Marsupials, Primates, Artiodactyls, Insectivores, Equapoids, etc. Thus, the diversity of living organisms is classified.
List of animal classes
Let's start with our smaller brothers, whose representatives - cats and dogs - each of us came across in everyday life. The aforementioned pets belong to the Mammals class, so named for the way they feed their offspring. It has 25 orders, 140 families, about 4600 species. It includes a huge blue whale, and a deer, and a wolf, and a mouse.
However, the Insect class is the most numerous on earth. It’s enough to mention that it prevails over the class of mammals by three orders of magnitude! The class of insects has about 30 orders, 1,053,578 species (as of the end of 2013). The largest orders include Coleoptera, Lepidoptera, Diptera, Hymenoptera, Hemoptera, and Orthoptera.
As you can see, different classes demonstrate different properties of living organisms.
Amphibians (on the contrary, the “narrowest” class) have about 3.5 thousand species, reptiles - about 7 thousand. This small class has adapted to the environment, preferring an underground and underwater lifestyle.
The Bird class unites 8.6 thousand species. Plumage is inherent in them, both helping during the flight, and maintaining a constant body temperature. Reproduction occurs by laying eggs. By the way, did you know that birds appeared as a result of the development of one of the branches of dinosaurs? After all, in a reduced format, they preserved the generic properties of the giants that once reigned on Earth: tubular bones, keel structure of the body and, finally, the method of reproduction.
Class Pisces has about 20 thousand species. They are adapted to life in water, for which they are endowed with gills and fins.
Animal records
Indeed, a person is pleased with the variety of living organisms that inhabit the earth and seas with oceans. Sometimes nature shows real phenomena. Let's consider some of them. The largest animal is a blue whale, reaching a length of thirty-five meters. Even a newborn kitten is already pulling two tons. The fastest bird, the peregrine falcon, reaches a speed of 350 km / h in a dive flight. Recognized builders, termites, build their own "skyscrapers" termite up to 15 m high; beavers, dam builders, are not inferior to them - for example, such a dam (Montana state) is 750 meters long. The cheetah reaches a speed of 160 km / h at the time of its cast.
The best "actor" in the animal kingdom is the Indian mantis. It looks extremely similar to an orchid flower, and prey insects take this predator insect for a source of nectar.
The longest snake is the South American anaconda - up to 8 meters. Proteins are considered super reliable barometers: in 10 hours they sense the beginning of a storm, which they give out by their behavior. The largest flying bird, a trumpeter swan, weighs 22 kg, the smallest, a hummingbird, is 20 g. The loudest voice of a howler monkey (American tropics): it can be heard for 5 kilometers. The most sensitive beast is a lynx, it clearly distinguishes sounds at a distance of one kilometer. The list goes on - page by page.
The properties
The properties of living organisms were identified in the course of research as generic characters that identify them and separate them from inanimate nature. Biologists managed to analytically generalize the diversity of the animal world at the level of properties. Indeed, all living organisms have common (generic) properties:
- Unified chemical composition. In the composition of living organisms, the same chemical elements are found as in inanimate nature.
- Open character. On the one hand, they use external sources of nutrition and energy, and on the other, waste of their life activity, and after death they themselves become part of the environment.
- Carry out self-regulation, self-organization in relation to external factors.
- Self-reproducing, with each generation reproducing the properties of the living organisms that generated it.
- Variable in order to better adapt to the environment, adapting to its changes for effective survival.
- Grow and develop. If growth should be understood as an increase in length and mass, then development is a change in the most diverse characteristics of a living organism.
- Excitability. This property determines the informational self-coordination of the body, as well as the regulation of its characteristics of interaction with the environment.
- Discreteness. Each living organism can be represented as a combination of individual tissues, systems, organs, cells.
It should also be noted that all the above signs of living organisms only characterize them when they interact in a complex. Taken separately, they are not unique and peculiar to inanimate nature. So, for example, an ordinary body of water has an exchange of energy and substances, growth is a property of crystals, celestial bodies - stars, as you know, are subject to evolution.
What all living organisms consist of
As you know, all living organisms have an inherent cellular structure. The animal cells themselves are small: from 10 to 100 microns. Cells of various tissues differ in shape (for example, skin cells are scyphoid or flat, blood cells are oval, and muscle cells are elongated).
The cell itself is surrounded by a membrane, a membrane of “directed selective action”. It works as a checkpoint: it lets some substances inside and others out. The inside of the cell is filled with a moving dense and granular fluid - the cytoplasm. Note that the cell of a living organism also has a certain cytoplasmic structure, but we will consider it later. “Bubble transport” moves along the cytoplasm - vacuoles that carry nutrients and remove waste products.
Surrounded by cytoplasm, the cell has a rounded dense nucleus - a storage of chromosomes. They control and regulate the reproduction and heredity transmitted from the mother cell - the daughter.
Chromosomal differences in living organisms
The external signs of living organisms considered by us above - the ability to move, grow and develop, multiply - can be supplemented by internal, invisible to the naked eye. Take, for example, the number of chromosomes (structures containing DNA located in the cell nucleus). It is noteworthy that in the cells of different organisms they are present in different quantities. The man has 46, the gorilla 48, the horse 64, the dog 78. The butterfly has 380 chromosomes, and the ant Myrmecia pilosula is “deprived” of them: their female has 2 pieces, and the male has only one.
Cytoplasm as a set of organelles
Continuing to study at the cell level what all living organisms consist of, we will examine the cytoplasm through a microscope. We, armed with optics, will see that it is heterogeneous and is a collection of special cellular organs (organelles). The endoplasmic reticulum is composed of numerous membranes penetrated by the smallest channels. At this net, “protein factories” are grouped — compact, rounded ribosomes. Another organelle named after the Italian scientist Camilo Golgi Golgi apparatus. It is a stack of pouch membranes that forms fats and carbohydrates. "Stomach cells", lysosomes, break down carbohydrates, proteins, fats. They, grouping around fissile elements, make up the digestive vacuole.
Another organoid responsible for heredity is the cell center, the basis of which is two oblong round bodies.
All organelles of a living cell work harmoniously and purposefully, ensuring its vital activity. This process is so complicated that a separate branch of science - cytology - studies what all living organisms consist of.
Main fabrics
Our previous considerations determined the structure of the smallest "brick" of the body - the cell. However, the structure of the body can also be considered at the tissue level.
Similar in structure and functionality, the cells that cover the bodies of animals, their internal organs, are called epithelial. These protective cells are tightly adjacent to each other, which does not prevent them from secreting, isolating waste substances and absorbing interacting with them.
As you can see, living organisms on Earth have an uneven tissue structure. Connective tissues make up the skeleton, the skeleton of the body. These include bones, cartilage, ligaments, tendons. Connective tissues include blood. It has a dual function - the duct (supplying organs with oxygen and taking away the exhaust carbon dioxide from them) and the waiter (supplying the customers with nutrients from the “kitchen” - intestines - organs - and carrying “eaten” at the cellular level from them to the excretory organs (microslag )).
Muscle tissue is the "hydraulics of the body." They are responsible for motor activity and are also a protection and support for internal organs.
Nerve tissues, consisting of special cells - neurons - perform all the "fine tuning of a living organism": both the internal coordination and synchronization of the work of its organs, and the coordinated perception by the sensory organs of environmental signals. Thus, on the other hand, determining in more detail what all living organisms consist of, we can also say: from tissues. They are studied by the science of histology.
Output
Nature does not demonstrate random combinations of animal species, but regular types of existing cohabitations. Any kind of animal lives in its natural community. Often, purposeful, but ill-conceived human activity destroys these established, established relationships. Unconditional harm is caused by forced deforestation, technological pollution of rivers. The “achievements” of recent centuries are the destruction of tens of thousands of animal species. Science is called upon not only to stop people by realizing by them with what, in fact, the natural environment they interact, but also to harmonize these connections. It is no coincidence that biology studies a living organism (grade 6): the desire to protect the surrounding nature is instilled in Russians from childhood.
At the same time, at the end of the 20th century, the interaction between man and nature is determined by the factor that, according to Academician Vernadsky, the biosphere has changed qualitatively, enriched by rational human activity, evolved and become the noosphere (a sphere that takes into account, among other things, the aspect of human care for the surrounding animal world )
Evidence of this is the reserves and national parks, scientific work on the study and restoration of rare species, the popularization of biology. Among the species saved from extinction, one can name the bison, bison, marsupial Australian bears, sables, monk seals. The list goes on.
Speaking about cellular theory, we can say that modern biology has developed a special technology for creating stem cells from animal skin cells to save endangered species. Further, the obtained stem cells can be transformed into gametes - eggs and sperm of animals, and with their help completely recreate the embryo of the animal.