The adaptability of organisms to their environment is inextricably linked with their viability, ability to compete (competitiveness) And leaving normal offspring.
Viability
Animals
Plants
Butterfly body coloration
The cat and its wild relatives (tiger, leopard) hunt from ambush, stealing prey. All cats take care of themselves and lick their fur so that there is no smell. After all, the victims should not smell the predator. A cat hunts most often in the dark, because, hiding, at this time it becomes less noticeable. Therefore, all cats see well in the dark. The cat is a solitary animal, she "walks by herself"; Therefore, these animals are difficult to train.
A completely different matter is the dog. Canine relatives (wolves, jackals) mostly hunt in packs, so they are very sociable and easily get used to obey their leader. The dog can be trained and becomes very obedient. Dogs lick themselves very rarely and smell like a dog - after all, these animals do not sit in ambush. To find prey, the dog and its relatives use their keen senses. It is excellent in dogs, these animals can follow the trail for a long time.
The evolutionary process implies constant updates, the emergence of useful features, their fixation in the organisms of living beings. And these changes are not necessarily manifested at the genetic level. Idioadaptation is very important - adaptations of animals, plants and microorganisms to specific habitat conditions, environmental factors and physical characteristics range.
The mechanism for the emergence of adaptations is a deep evolutionary process that forms the necessary features over time, gradually. Fixing the necessary characteristics in the genome of living beings for manifestation in future generations.
Adaptations, or adaptations of organisms
Very often you can find an organism of plant or animal origin, which has some unusual feature in structure, behavior or appearance. For example, stick insects, which in appearance do not differ at all from a tree branch. Or a hoverfly, which has exactly the same color as a wasp. Among plants, examples are thick-stemmed fleshy cacti, stilted and aerial roots, support roots.
In any case, all these are adaptations to the environment, conditions environment or protecting yourself from other beings. Such phenomena are very important because they are important stages in the evolutionary process. The mechanism for the emergence of adaptations is always based on genetic selections and the fixation of important and necessary genes encoding the manifestation of a particular trait. For example, the gene responsible for changing the color of a chameleon was formed in the genome of these animals several thousand years ago and is still inherited by all future generations.
Plant adaptations: general characteristics
Plant adaptations are integral part their lives. All of them can be divided into several main groups.
- To the temperature conditions of the environment.
- Humidity.
- pollination methods.
- To food consumption.
The mechanism for the emergence of adaptations corresponds to the same basics - evolutionary changes with the consolidation and transmission by inheritance of the signs necessary in specific conditions. Therefore, if any plant has adapted to the territory, environmental conditions, temperature, then it will certainly pass on all the features for a comfortable existence to all its future generations.
Plants in dry conditions
Under the temperature regime, in which too high values and constant sunny days prevail, adaptations in plants have a pronounced character, aimed at reducing the evaporation of moisture. And also to preserve body weight and nutrients along with bound water inside the stem.
To do this, the sheet plates are reduced to a minimum, or completely modified. by the most a typical example are desert plants - cacti. The harsh conditions of existence under the scorching sultry sun forced these plants to transform the leaves into prickly needles, and the stem into a thick fleshy trunk filled with parenchymal cells (the main tissue) with a large amount of bound and free water.
The mechanism of cactus adaptation shows very clearly how skillful plants can be in their adaptations. Thanks to the spines, the plant does not evaporate water from the surface of the leaves, which means it saves a large amount of it. In addition, in the stem, modified into a thick fleshy trunk, there is an accumulation of a number of substances that retain water. For example, they accumulate:
- hydrophilic protein molecules;
- proline (an amino acid that retains water);
- monosaccharides and various organic acids.
Also, the mechanism for the emergence of cactus adaptations includes the production of hormonal compounds that inhibit the action of growth hormones (gibberellins, auxins). This allows plants to quickly stop their growth when adverse conditions occur that last for a long time.
Adaptations for different types of pollination
Another striking example of adaptations in plants is their ability to adapt to pollinators. For example, wind-pollinated forms produce dry and light seeds that will simply disperse even with slight air movements.
If the plant is insect pollinated, then it forms flowers of a certain structure and color:
- brightly colored;
- large or collected in large inflorescences;
- with a strong pleasant aroma.
The structure of the flower itself can also be adapted to the pollinator. There are plants that are pollinated strictly a certain kind birds or insects.
Cross-pollinating or self-pollinating plants in the flower structure have long stamens and a deep-set pistil to allow the pollen to land on the stigma. Each of these devices plays important role in reproduction and is also fixed hereditarily in the genome.
Excess moisture conditions for plants
In tropical and subtropical habitats, excessive air humidity is often a phenomenon. After all, it is known that in some areas tropical downpours can go for more than a month. Of course, such an excess of water is very harmful to plants. Therefore, some species have formed certain adaptations that minimize such an impact of nature. These are hydathodes - water mouths that increase the amount of water released by the plant. It comes out in drops. This phenomenon is called guttation.
Also, adaptations to excess moisture in plants are large leaf plates with huge amount stomata. Accordingly, transpiration is also enhanced.
The mechanism of the emergence of adaptations in animals
Representatives of the fauna are forced not only to adapt to environmental conditions, but also to protect themselves from the attack of stronger individuals, for whom they are food. This led to the formation of several types of adaptations in animals:
- change in the shape of the body and limbs, wool (skin, feather) cover;
- protective coloration;
- mimicry (imitation of more protected and dangerous animals);
- warning coloring;
- intimidating behavior.
A striking example of adaptations by changing the shape of the body, limbs and covers are birds (feathers, keel, light skeleton, streamlined body shape). Also aquatic mammals and fish that have tails and fins, a smooth surface, the absence of a powerful coat. But they have air bubbles, membranes on the paws of flippers (marine mammals).
It occurs in many animals, both terrestrial and aquatic. For example, hiding in the grass, sea needles hiding themselves in algae. Chameleons, moths (rod-shaped caterpillars), kalima (butterfly imitating a leaf), variegated and gray colors of hares, and many other examples reflect adaptations in animals.
Mimicry, that is, imitation in order to protect oneself from being eaten and attacked, is characteristic of, for example, hoverfly flies (resembles a wasp), some species of snakes that copy poisonous snakes, and so on.
The warning coloration of insects and animals is aimed at an honest warning about the inedibility of the species, its toxicity. An example is poisonous snakes, wasps, bees, bumblebees, ladybugs and other representatives. These are very common adaptations in animals.
Frightening behavior is hissing, growling, jumping to the side, releasing body fluids (octopus and squid ink, skunks). This also includes the features of some animals, which form flocks in the cold season to facilitate the acquisition of food.
All of these devices have an evolutionarily formed and genetically fixed mechanism of formation.
Polar bear adaptations
The mechanism for the emergence of polar bear adaptations was formed in extremely cold habitats. All of its adaptations are aimed specifically at keeping warm and getting food. These include:
- patronizing white color (camouflage);
- a thick layer of subcutaneous fat, which plays a dual role: thermal insulation and lightening of body weight when swimming and diving;
- thick dense and warm fur covering the entire surface of the body.
Thanks to its adaptations, the polar bear can not be afraid of even the most severe cold. And the white coloring allows him to quietly sneak up to the source of food - the seals.
Adaptations of underground mammals
The most prominent representative is, of course, the mole and all its relatives (zokors, mole rats and others). Therefore, on his example, consider adaptation. The mechanism for the emergence of mole adaptations is associated with an underground habitat, devoid of some important light, a sufficient amount of moisture, and heat. Therefore, the adaptations of this animal are as follows:
- powerful burrowing limbs;
- lack of vision;
- thick subcutaneous layer of fat;
- smooth and hard coat of black color;
- streamlined body shape.
Adaptations of large desert animals
These primarily include camels, their various types. The mechanism of the appearance of camel adaptations was formed under conditions of lack of moisture and high temperatures. Adaptations of the following nature:
- the presence of glands that eliminate excess salts in the body;
- decreased sweating;
- the ability to starve for a long time, losing body weight by a third;
- special features of digestion and metabolism;
- the presence of humps filled with fat that stores bound water;
- rapid saturation with water to replenish internal reserves.
All these adaptations make desert conditions quite comfortable and acceptable for camels.
Having worked through these topics, you should be able to:
- Formulate definitions in your own words: evolution, natural selection, struggle for existence, adaptation, rudiment, atavism, idioadaptation, biological progress and regression.
- Briefly describe how an adaptation is preserved by selection. What role do genes play in this, genetic variability, gene frequency, natural selection.
- Explain why selection does not result in a population of identical, perfectly adapted organisms.
- Formulate what genetic drift is; give an example of a situation in which it plays an important role and explain why its role is especially great in small populations.
- Describe two ways in which species arise.
- Compare natural and artificial selection.
- Briefly list aromorphoses in the evolution of plants and vertebrates, idioadaptation in the evolution of birds and mammals, angiosperms.
- name biological and social factors anthropogenesis.
- Compare the effectiveness of consumption of plant and animal foods.
- Briefly describe the features of the most ancient, ancient, fossil man, a man of the modern type.
- Indicate the features of the development and similarities of human races.
Ivanova T.V., Kalinova G.S., Myagkova A.N. "General Biology". Moscow, "Enlightenment", 2000
- Topic 14. " evolutionary doctrine." §38, §41-43 pp. 105-108, pp. 115-122
- Topic 15. "The fitness of organisms. Speciation." §44-48 pp. 123-131
- Topic 16. "Evidence of evolution. Development of the organic world." §39-40 pp. 109-115, §49-55 pp. 135-160
- Topic 17. "The origin of man." §49-59 pp. 160-172
Consider pictures 158-163. What are the adaptations of the organisms depicted in the figures to the living conditions? Think about whether these adaptations will persist in organisms if their living conditions change.
All organisms have a variety of adaptations to environmental conditions. These adaptations develop in the course of evolution in two stages. Initially, due to mutational and combinative variability, new signs appear in organisms. Then these signs are tested by natural selection for their compliance with environmental conditions.
Examples of adaptations of organisms. Examples of adaptations of organisms to living conditions are so numerous that it is almost impossible to describe them all. Let's just give some examples.
Rice. 158. Protective coloration in animals: 1 - solid coloration of winter plumage in tundra partridge; 2 - dissecting coloration in axis deer
Morphological adaptations include those found in different organisms, Various types patronizing, warning coloring, camouflage and passive protection.
Protective coloration develops in individuals living openly, which makes them less noticeable against the surrounding background. This coloration is continuous White color plumage of a tundra partridge in winter), if the surrounding background is homogeneous, or dismembering (light and dark dots on the skin of axis deer), if spots of light and shadow alternate on the surrounding background (Fig. 158). The effect of patronizing coloration is enhanced by the corresponding behavior of the animal. At the moment of danger, they hide, which makes them even less noticeable against the surrounding background.
Warning coloration develops in individuals that have chemical defenses against enemies. These include, for example, stinging or poisonous insects, inedible or burning plants. In the process of evolution, they developed not only toxic chemicals, but also bright, usually red-black or yellow-black colors (Fig. 159). Some animals with a warning coloration at the moment of danger show bright spots to the predator, take a threatening posture, which confuses the enemy.
Rice. 159. Warning coloration in poison dart frogs
Camouflage - protection, which is not only color, but also the shape of the body. There are two types of disguise. The first is that the camouflaged organism in its appearance resembles some object - a leaf, a knot, a stone, etc. This type of disguise is widely found in insects: stick insects, bugs and moth caterpillars (Fig. 160).
Rice. 160. Camouflage in leaf bugs
The second type of disguise is based on the imitative resemblance of unprotected organisms to protected ones. So, harmless glass-bottle butterflies with the color of the abdomen resemble stinging insects - wasps, so insectivorous birds do not touch them (Fig. 161).
Rice. 161. Glass Butterfly Disguise
Means of passive protection increase the probability of preserving the organism in the struggle for existence. For example, tortoise shells, mollusk shells, hedgehog quills protect them from enemy attacks. Thorns on the stems of roses and thorns in cacti prevent the eating of these plants by herbivorous mammals (Fig. 162).
Rice. 162. Means of passive protection in prickly pear cactus
Physiological adaptations ensure the resistance of organisms to changes in temperature, humidity, illumination and other conditions of inanimate nature.
So, when the ambient temperature drops in amphibians and reptiles, the level of metabolism in the body decreases and winter sleep begins. In birds and mammals, on the contrary, when the ambient temperature drops, the metabolism in the body increases, which increases heat production. The dense feather, wool and subcutaneous layer of fat that develops at the same time prevents the body from losing heat (Fig. 163).
Rice. 163. Winter squirrel fur has a thick undercoat
Behavioral adaptations are found only in animals with a highly developed nervous system. They represent various forms of behavior aimed at the survival of both individual individuals and the species as a whole.
All behavioral adaptations can be divided into congenital and acquired. Congenital include, for example, mating behavior, protection and rearing of offspring, avoidance of predators, migration. So, a lioness, when licking her cubs, remembers their smell. The same process awakens in her the need to protect the cubs from enemies (Fig. 164, 1).
Rice. 164. Behavioral adaptations of organisms: 1 - lioness licking cubs; 2 - Japanese macaques basking in a hot spring; 3 - waterfowl wintering on a non-freezing reservoir in the city
Acquired behavioral adaptations also play an important role in the life of animals. For example, the northernmost species of monkeys - Japanese macaques, found in the north of Japan, switched to a snow-water lifestyle (Fig. 164, 2). In winter, with the onset of more severe frosts, these monkeys descend from the mountains to hot springs, where they bask in warm water. Another glaring example. IN major cities Central Russia has changed the behavior of migratory birds. So, some waterfowl stopped flying to warmer climes for the winter. They gather in large flocks on non-freezing water bodies, where there is always the necessary food (Fig. 164, 3).
Relative feasibility of devices. All adaptations in organisms are developed in the specific conditions of their habitat. If environmental conditions change, devices may lose their positive value, in other words, they have a relative expediency.
There is much evidence of the relative expediency of adaptations: the body's defense against some enemies is ineffective against others; the behavior of the organism may become meaningless; An organ that is useful in one environment is useless in another. For example, the warbler, thanks to her parental instinct, feeds the cuckoo, hatched from an egg thrown into the nest by a cuckoo (Fig. 165).
Rice. 165. Relative expediency of adaptations of organisms - warbler feeding cuckoo
So, the main result of the action of the driving forces of evolution is the emergence of new adaptations and the improvement of existing adaptations in organisms. Since the conditions for the existence of organisms change, there are no absolute adaptations in nature, and the process of their appearance is endless. In individuals belonging to the same species, differences in the available adaptations are insignificant. The consolidation of these differences in conditions of isolation leads to the emergence of new species, i.e. to visualization.
Lesson learned exercises
- How do individuals adapt to their environment?
- What is the relative expediency of devices? Illustrate your answer with examples.
- Can organisms in the course of long evolution develop absolute, i.e. perfect, adaptations? Justify your answer.
Many birds have mastered the ground-air habitat. The adaptation of birds to flight became possible due to many changes in appearance and internal structure.
The main features of the adaptation of birds to flight
- Double breath.
- The flight muscles contain a large number of myoglobin.
- Feather cover.
- Lightweight skeleton.
- Developed circulatory system.
- Fast metabolism.
- Modification of the forelimbs in the wings.
- Streamlined body shape.
- There is a special bone - the keel.
- Warm-bloodedness.
- One ovary.
- Reduced number of bones.
- The cerebellum is enlarged.
- Well developed nervous system.
How are birds adapted to fly?
In birds, the lungs do not have the ability to expand or contract as they do in humans. Air bags do all this work. When inhaling and exhaling, fresh air moves through the lungs of a bird, which is stored in bags. For this reason, breathing in birds is called "double". In birds, the flight muscles contain a lot of myoglobin to supply enough oxygen.
The internal structure of the bird diagram
Birds have to eat a lot to get a lot of energy. They have a very well developed circulatory and respiratory system. The average pressure of birds is about 130 mm Hg. Art., while in mammals it is only 95 mm Hg. Art.
Birds have a very fast metabolism, body temperature reaches from 40 to 42 degrees. Heat body significantly affects all vital processes, and muscle contraction occurs many times faster.
To a large extent, the large muscles that move the limbs are located on the body, and the tendons already go to them.
Birds chew their food in the stomach, so all chewing processes are located inside the body, which improves their aerodynamics.
Feathers have feathers that do not need blood vessels, they are too light and soft. Also, in addition to all this, bird light a skeleton that is filled with air. And for better coordination of movements, the cerebellum was enlarged.
Adaptation of birds to the environment
Depending on the habitat, the external structure of birds is greatly modified. For example, a woodpecker has a beak that looks like a chisel. He uses it to get insects and larvae from the bark of trees. In addition, he has an overly long, sticky tongue and sharp claws that allow him to perform all the necessary tasks to continue living.
Birds that live in water bodies also have some changes. They have short lower limbs with swimming membranes and a continuous covering of feathers. Birds living in deserts and steppes have a protective color of feathers, they have excellent eyesight and strong legs.
Ostrich-like birds inhabit Africa. They cannot fly, as birds have underdeveloped wings, but their legs are well developed. Birds can reach speeds of up to 70 km / h, their weight is 50-90 kg, and their height is about 2.5-2.7 meters. Ostrich-like animals live in savannahs, deserts, and steppes.
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Birds of prey have large, curved beaks that are used to tear their prey into small pieces. Having powerful sharp claws, they cling to prey, after which they inflict fatal wounds on them or carry food to their nest. Predators can hover in the air for a long time, they have excellent sharp eyesight and excellent hearing.
