Adaptations of organisms to the environment conditions.

Lecture 2. Ecology of the individual is autecology. The basic inhabitancies.

Outline:

1. Ecological factors and their classification.

2. Adaptations of organisms to conditions of environment

Ecological factors and their classification.

Inhabitancy is a part of the nature surrounding alive organisms and affecting on them. On our planet, alive organisms have assimilated 4 inhabitancies: water, ground- air, soil and organism. The water environment was the first. Then alive organisms have assimilated the ground-air environment, they have created and occupied soil. A soil inhabitancy means not only actually soil, but also rocks of a superficial part lithosphere. Organism environment was assimilated by parasites.

Ecological factors are separate elements of inhabitancy which influence organisms. Each of inhabitancies is differed by features of influence of ecological factors. Ecological factors are divided into abiotic, biotic and anthropogenic ones.

Abiotic factors are components of the lifeless nature. They are climatic (light, temperature, humidity, wind, pressure, etc.), geological are earthquakes, eruptions of volcanoes, movement of glaciers, radioactive radiation, etc.), orographical (lay of the ground), edaphic or soil-ground (density, structure, рН, granulometric composition, chemical composition, etc.), hydrological (water, flow, salinity, pressure, etc.). Otherwise, abiotic factors are divided into physical, chemical and edaphic ones.

Biotic factors are influence of alive organisms between each other (interaction between individuals in populations and between populations in communities). Thus mutual relations can be intraspecific (interactions among individuals of one species) and interspecific (between individuals different species). According to type of interaction there are symbiosis, mutualism, komensalism, intraspecific and interspecific competition, parasitism, predatoriness, amensalizm and neutralism. Depending on influencing organism biotic factors are divided into phytogenic (influence of plants), zoogenic (animals) and микробогенные (microorganisms).

Anthropogenous factors are activity of the person resulting in direct influence on alive organisms, or in change of inhabitancy (hunting, trapping, pollution, soil erosion etc.). Thus, it is necessary to differentiate a person activity as biological organism and his economic activities (technogenic factors).

Ecological factors can influence an organism directly and indirectly. Indirect influence is carried out through other ecological factors. For example, high temperature can cause a burn (direct action), and it can result in dewatering organism (indirect influence).

Different ecological factors possess various variability in space and in time. One of them are rather constant (for example, force of gravitation, solar radiation, salinity of ocean), others are very much inconstant (for example, temperature and humidity of air, force of a wind).

Changes of environment factors can be periodic and acyclic. Periodic factors are regularly repeated in time (for example, change of air temperature and light exposure within day or year). Acyclic factors have no periodicity (for example, volcano eruption, an attack of predator). Periodic factors are divided into primary and secondary ones. Primary periodic factors are connected with the space reasons (light exposure, inflow, low tide, etc.). Secondary periodic factors appear as consequence of action of primary factors (temperature, quantity of fall-out, a biomass, efficiency, etc.).

Ecological factors influence on alive organisms differently: limiting, irritating, modifying and alarm. Limiting influence does impossible existence in the present conditions. Irritable influence causes biochemical and physiological adaptations. Modification influence causes morphological and anatomic changes of organisms. Alarm influence informs about changes of other factors of environment.

In the nature, ecological factors operate jointly, that is, in a complex. A complex of factors under which action the basic vital processes of organisms are carried out, are called life conditions including normal evolution and breeding. Conditions in which breeding does not proceed, is called conditions of existence.

Adaptations of organisms to the environment conditions.

Adaptations are various adaptations to the inhabitancy, which organism develops during evolutions. Adaptations are developed at different levels of the organization of alive matter. Ability to adaptation is one of basic properties of the alive matter, providing an opportunity of its existence. Adaptations are developed under action of three basic factors: a heredity, variability and natural (and also artificial) selection.

There are three basic ways of the organism adaptation to conditions of the environment: an active way, a passive way and avoiding adverse influences.

Active way is strengthening of resistibility, development regulatory processes, which make it possible to carry out all vital functions of organism, despite of deviations of factor from an optimum. For example, maintenance of a constant body temperature of warm-blooded animal (birds and mammals), which is an optimum for proceeding biochemical processes in cells.

Passive way is a submission of vital functions of an organism to change of environment factors. For example, transition under adverse conditions of environment in a condition of anabiosis (the latent life) when the metabolism in organism is practically completely stopped (winter rest of flowerings, preservation of seeds and dispute in soil, catalepsy of insects, hibernation of vertebrate animals, etc.).

Avoiding of adverse influences is a development by organism of such life cycles and behavior which makes it possible to avoid adverse influences, for example, seasonal migrations of animals.

Usually species adaptation to environment is carried out by that or other combination of all three possible ways of adaptation.

Adaptations can be divided into three types: morphological, physiological and ethological.

Morphological adaptations are accompanied by change in a structure of organism (for example, modification of a plants leaf of deserts). Morphological adaptations of plants and animals result in formation of the certain vital forms.

Physiological adaptations are changes in physiology of organisms (for example, ability of a camel to provide an organism by moisture by oxidation of fat stocks).

Ethological adaptations are changes in behaviour (for example, seasonal migrations of mammals and birds, a hibernation confluence of the winter period). Ethlogical adaptations are characteristic for animals.

Alive organisms are well adapted for periodic factors. Acyclic factors can cause illnesses and even death of the alive organism. The person uses it, applying pesticides, antibiotics and other acyclic factors. However, long influence of these substances also can cause adaptation to them.

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