Population, as a form of the species, and its main criteria. Кадырбекова Дияра 041 -1
A population is all the organisms of the same group or species who live in the same geographical area and are capable of interbreeding. In ecology the population of a certain species in a certain area is estimated using the Lincoln Index. The main criterion for selection population - the ability for the free exchange of genetic information - panmixia. • Population genetics is the study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow.
There are three categories of populations: 1. Geographical populations - occupy an area of vast geographical areas, but retain the ability to panmixia. Characterized by common adaptations to climate and terrain. 2. Environmental - inhabit a certain habitat; 3. (Elementary (local) - inhabit part of the biotope. 1 2 Ареал 3
The main characteristics of the population are: density, abundance, fertility, mortality, age structure, the distribution within the territory and the growth rate. The density of population is determined by the number of individuals per unit area or volume. Number - the total number of animals on the allocated territory. Populations of many species have properties that allow them to regulate their numbers. Maintaining abundance, optimum in the given conditions, is called homeostasis population. Homeostatic capabilities of populations are different and they are carried through the relationship of individuals to each other and with the environment. Birth rate is the number of new species as a result of breeding at a time. Fertility depends on the rate of sexual maturation, the number of generations per year, the ratio in the population of males and females. Greatly the birth rate is determined by food supply, the ability to bring up the offspring and the influence of environmental conditions.
Mortality - an indicator of the number of deaths in a population of individuals over a certain period of time. It can be caused by the influence of abiotic environmental factors (low and high temperature, heavy rains, hail, excessive or insufficient moisture), biotic factors (lack of food, infectious diseases), human factors (pollution, destruction of animals, trees). Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using "per unit time" for measurement. In demographics and ecology, population growth rate (PGR) is the rate at which the number of individuals in a population increases in a given time period as a fraction of the initial population. Specifically, PGR ordinarily refers to the change in population over a unit time period, often expressed as a percentage of the number of individuals in the population at the beginning of that period. The age structure of a population is the distribution of people among various ages. In graphic form, age structure is portrayed as an age pyramid whose relatively broad base indicates the number of children while the peak reflects the increasing likelihood of death as people age. A population whose age structure has a very broad base and a sharp narrow peak is said to be “young, ” while a structure whose base is not much wider than the rest of the pyramid is “old. ”
Population dynamics is the branch of life sciences that studies short-term and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes. Population dynamics deals with the way populations are affected by birth and death rate, and by immigration and emigration, and studies topics such as ageing populations or population decline. One common mathematical model for population dynamics is the exponential growth model. With the exponential model, the rate of change of any given population is proportional to the already existing population. Population statistics is the use of statistics to analyze characteristics or changes to a population. It is related to social demography and demography. Population statistics can analyze anything from global demographic changes to local small scale changes. For example, an analysis of global change shows that population growth has slowed, infant mortality rates have declined and there have been small increases in the aged.
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph. In order to be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating). Polymorphism is common in nature; it is related to biodiversity, genetic variation and adaptation; it usually functions to retain variety of form in a population living in a varied environment. Polymorphism results from evolutionary proc, as does any aspect of a species. It is heritable and is modified by natural selection. In genetic polymorphism, the genetic make-up determines the morph. Polymorphism as described here involves morphs of the phenotype. Sexual dimorphism, the differences in appearance between males and females of the same species, as in color, shape, size, and structure, that are caused by the inheritance of one or the other sexual pattern in the genetic material. These differences may be extreme, as in the adaptations for sexual selection seen in the exotic plumes and colors of the male birds-of-paradise, or for protection, exemplified by the great size and huge canine teeth of the male baboon. Many birds show at least some dimorphism in color, the female being cryptically colored to remain concealed on the nest, while the more colorful male uses display in courtship and territorial behaviors. In at least a few species of mammals, females tend to be larger than males. The same is true of many non-mammalian vertebrates and numerous invertebrates as well. The spiny lizard Sceloporus jarrovi is sexually dimorphic in feeding habits: the equal-sized males and females seek out different sizes of prey.
Population is characterized by the following main features: v population is a form of the species; v integrity (territorial community, genotypic and phenotypic community); v heterogeneity of individuals in the population; v self-regulation.
Management of natural populations control population suppression Maintenance (security) Providing growth
The term "species" was first introduced in the biology by the English botanist John Ray (1628 - 1705)
Darwin • Species actually exist in nature. • Species appear, disappear, evolve, change, give rise to other species. Linnaeus Recognized the real existence of species in nature. • Considered that species are permanent and unchanging. • Lamarck • He believed that the term "species" was invented by man for easy classification. • Denied the real existence of species in nature, imagined nature as a set of ever-changing series of individuals. • Considered only individuals are real.
Criteria of the form-signs by which individuals are united in one form or the grounds by which individuals of different species can be distinguished. criterion of the form additional main Biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. Biotope is almost synonymous with the term habitat, which is more commonly used in English-speaking countries. However, in some countries these two terms are distinguished: the subject of a habitat is a species or a population, the subject of a biotope is a biological community. It is an English loanword derived from the German "Biotop", which in turn came from the Greek bios='life' or 'organism' and topos='place'. (The related word geotope has made its way into the English language by the same route, from the German "|Geotop]]". ) The word biotope, literally translated, means an area where life lives
b a s i c t h c e r i f t o e r r m i a Name of criteria characteristics of individuals according to criteria exception Morphological The similarity of the external and internal structures of organisms Types of doubles, sexual dimorphism, polymorphism Geographical Occupy a certain area Cosmopolitans. The coincidence of areas of different species Ecological Similarity method of Ecological niches feeding, habitat, sets of of different environmental factors species overlap necessary for existence
A d d i t i o n a l c r i t e r i Physiological t h e f o r m Different types have similarity processes of life. The presence of interspecific hybrids Biochemical o f The similarity of the processes of life and the availability of fertile offspring during crossing Similarity in biochemical parameters the composition and structure of proteins, nucleic acids There are very similar species in biochemical composition Ethological The similarity in behavior. Especially in the mating season (rituals of courtship, marriage songs, etc. ) There are species with similar behavior Historical The generality of the ancestors, a common history and development of the form Cytogenetic-cytological Individuals of one species are crossed with each other and produce fertile offspring (based on the similarity of the number of chromosomes, their form and structure) Chromosomal polymorphism within a species, many different types have the same number of chromosomes. Genetic isolation of species. That mechanisms are in isolation. The most important of them - is the death of the male gametes (genetic incompatibility), the death of zygotes unviable hybrids, their sterility, finally, the inability to find a sexual partner and give a viable fertile offspring The dog and the wolf, poplar, willow, canary finch and produce fertile offspring. (The presence of interspecific hybrids)
Species diversity is the effective number of different species that are represented in a collection of individuals (a dataset). The effective number of species refers to the number of equally-abundant species needed to obtain the same mean proportional species abundance as that observed in the dataset of interest (where all species may not be equally abundant). Species diversity consists of two components: v Species richness v. Species evenness Species richness is a simple count of species, whereas species evenness quantifies how equal the abundances of the species are
Species set of individuals that have similarity of morphological, physiological, biochemical features, freely interbreeding and producing fertile offspring, like their parents; adapted to specific conditions of life and the nature of a particular area.