Ecology, ecogenetics

Ecology of populations

By population we call a set of individuals of the same species inhabiting a certain territory in a given time period.

Population ecology examines the influence of ecological factors on populations (demecology).

In a population, individuals are distributed in such a way that each has a probability of participating in the reproduction of the population's offspring. It is therefore a living system in which not only the biological properties of individuals are manifested, but also the biological properties of the entire group. A population can thus: grow, age, differentiate, maintain itself, have a certain structure, birth rate, mortality, dispersion, etc. Population ecology makes it possible to examine these characteristics, thereby contributing to a more complete knowledge Gene pool nature.

Dispersion

Dispersion (spreadsl) – distribution of individuals in the population, informs about the location of individuals in the inhabited area. Divided:

• linear;
• flat;
• spatial.

Population density

• Population density is related to the distribution of individuals - it is given by the number of individuals per unit area – abundance.

Population density is subject to species-related changes:

• oscillations (fluctuations in frequency during 1 year);
• fluctuations (fluctuations in abundance over several years, the result of mortality and birth rates).

• Some species overgrow from time to time. Proliferation phase: gradation → gradation peak → culmination → retrogradation → latency → pregradation → progression with a new gradation peak.
• Fluctuations in the number of populations are influenced by: climatic conditions, diseases, human interventions, ...
• As a result of the uneven distribution of the vital components of the environment, animals are scattered in the landscape non-randomly and unevenly.
• The social structure of the population and the gender ratio also play a role.

Age structure of the population

• Another characteristic of the population is its age structure. From this point of view, we can divide the population into 3 categories:

1. pre-productive;
2. productive;
3. postproductive (old individuals).

• Natality (multiplicity) is directly dependent on metabolic rate and inversely dependent on size.
• Mortality (mortality rate).

The animal population is subject to a kind of spatial activity, either during movement due to the expansion of the species, or also in search of warmth, reproduction, food, etc. Vertical activity (chamois) is interesting.

A significant feature is the form of population growth:

1. closed growth (S curve) – the maximum population density fluctuates around the so-called carrying capacity of the environment;
2. open growth (J curve) – a gradual increase at first, then a sharp rise and finally a steep decline.

Ecogenetics

• It studies hereditary differences in people's reactions to physical, biological and chemical environmental influences.
• It follows on from pharmacokinetics and the development of modern medicine.

Physical influences

• UV radiation – a strong mutagen for unicellular organisms. In humans, it is needed in small amounts for the production of vitamins. Protection is provided by the pigment.
• Pigmentation is polygenically inherited, the level of protection is given genotype.
• UV radiation causes Mutation, these are removed by reparation activities enzymee. Persons with repair disorders have an increased risk of malignancies.
• Diseases associated with sensitivity to UV radiation:

• Xeroderma pigmentosum is an autosomal recessive disease. The skin is extremely sensitive to sunlight, cancers form at an early age in exposed areas. Endonuclease defect + mutation of about 6 others genes, individuals with a combination Alleles Aa affected less.

• Ataxia teleangiectasia.

• Bloom syndrome (erythema congenitale teleangiectaticum Bloom) is an autosomal recessive syndrome of chromosomal instability.

Foodstuffs

Fats

• Hyperlipemia with subsequent atherosclerosis, ICHS, Heart Attack.
• Individual risk is determined not only by lifestyle, but also by genetic disposition.
• The metabolism of fats depends on their transport in the blood, their binding to cell receptors and the breakdown of fats in cells.
• The amount of fat can be influenced by diet and medication.

Salt

• the sensitivity of sensors to salty taste is influenced by the threshold of sensitivity to salty taste and gender habits;
• genetically conditioned, modified in childhood;
• persons with a dominantly inherited disorder of transport of Na+ from cells and K+ into cells (Na-K pump);
• arterial hypertension.

Milk

• reduced lactase activity → undigested lactose → GIT problems;
• AR hereditary lactase deficiency - atrophic enteritis;
• degenerative changes in the renal canals

Flour

• Persons with Celiac disease (gluten enteropathy) – it is the inability to break down gluten in flour, nutrient absorption disorders, digestive difficulties. Inheritance irregularly dominant. The condition can be modified by diet (gluten-free).

Proteins

• Toxic for children with congenital disorders of amino acid metabolism (e.g. PKU, diet low in phenylalanine).

Alcohol

• Alcoholism it is conditioned by social factors and genetically.
• Alcohol dehydrogenases (ADH) – alcohol is metabolized in the liver to acetaldehyde (absorption already in the stomach).
• Tolerance to alcohol is also affected by the activity of acetaldehyde dehydrogenase (ALDH).

Inhalants

• dust (antitrypsin deficiency → pulmonary emphysema);
• smoking (lung cancers);
• Allergens (changes in the immune response, bronchial asthma).

Infection

1. Insulin dependent DM (DM I.type):
   • manifestation in childhood;
   • the antigenic makeup (HLA haplotypes, DR3 and 4) is inherited – in 95% of those affected;
2. Immune disorders:
   • Agama-globulinemia (GR);
   • aplasia thymus;
   • AIDS, mononucleosis due to the EB-virus;
3. Ulcer disease of the stomach and duodenum:
   • Helicobacter pylori.
4. Jaundice, TBC, …

Links

• ws: Ekologie, ekogenetika

related articles

• Population polymorphisms
• Multifactorial Inheritance
• Origin and development of species
• Evolution