What is Population ecology?
A population is a group of individuals of the same species, occupying one specific space and which arises as part of a biotic community. A population has its own biological characteristics or attributes which it shares with its organism components but also has characteristics or attributes of the group, for example, birth rate, mortality, age distribution, genetic fitness, and growth. The properties of a population are density, birth rate, mortality, biotic potential, age distribution, dispersion, and r-k growth mode. The density of a population is the size of this concerning a defined spatial unit. In general, it is expressed as several individuals of the population per unit area or volume.
It is often more useful to know if a population is changing over time than it does know its abundance at any given time (e.g., number of African elephants in relation to medium-long term species conservation systems). Other indices such as those of relative abundance may be useful or the frequency of repeated events in a given unit of time. The densities of mammalian populations are a function of the trophic level and the animals' body size. The lower the trophic level, the higher the density and, at a given level, the larger the individuals, the higher the biomass (Kg/ha)
What is Population ecology?
Population ecology can be defined as the study of the factors that affect the population and how living and non-living factors influence the size, density, and dispersion of a population. Moreover, it belongs to the study of the factors that why a population changes over time.
Population density estimation methods
The Lincoln Index is a common capture/marking method used to estimate the population's total density in a defined area.
- The marking technique does not adversely affect animal mortality
- Animals are marked and released on the same site
- The marking technique does not affect the probability of recapturing
- The markings do not come off or lose
It is the ability of a population to grow through successive reproductions.
The birth rate equals the birth rate used for the human population. The maximum birth rate is the maximum theoretical production of new individuals in ideal conditions, considering as limits only physiological abilities. Generally, the birth rate is expressed as the ratio between the number of individuals born and the time (absolute birth rate or raw), or as newborn per unit of time per unit of population (rate of specific birth rate). Fifty protozoa become 150 in an hour, raw birth rate 100 per Now. The specific birth rate is 2 per hour per individual of the original 50.
Refers to the death of individuals who make up the population, is equivalent to the rate of deaths that are calculated in studies concerning human populations. So as with the birth rate, mortality can be calculated as the number of individual’s deaths in a given time or as a specific rate in terms of population units in whole or in part. Ecological mortality achieved (loss of individuals in one given condition), it is not constant, but as for the birth rate, it varies according to environmental conditions and with the population. There is a theoretical minimum of mortality constant for each population representing the minimum number of deaths in ideal non-limiting conditions. If the mortality rate were expressed as a fraction M, the survival rate is 1-M. If the mortality rate were expressed as fraction M, the survival rate is 1-M
Distribution by age
The relationship between the various age groups in a population determines its reproductive state and makes considerations about its future. According to numerous opinions, the populations with which they would have a "normal" or stable age distribution tend real distributions. Once you reach age stability, normal increases in birthrate or mortality result in temporary changes, with spontaneous returns to normal.
It is, therefore, possible to recognize three ecological ages:
A high young-adult ratio indicates that there will be a high future birth rate and a probable increase in individuals in the following season.
Rate rates Populations
It is realities in constant change, in constant change, density, birth rate, survival, age structure, and growth rate are all DYNAMIC parameters. The study of the change in the number of individuals of one population and the factors that justify the changes is called DYNAMICS OF A POPULATION. So what does it affect overtime? The rate you can obtain by dividing the change by a certain amount by the period of time during which the change occurred. You will find that "change" 'abbreviated to ecological formulations as Delta.
The intrinsic rate of natural increase
If we were to consider a non-limiting environment, the specific growth rate would be constant and maximum in favorable climatic conditions. It becomes an index of the intrinsic capacity of growth of that given favorable population conditions and characteristics of that particular age distribution. It is indicated by the letter r, which is the exponent of the differential equation, which expresses the growth of a population in a non-limiting environment.
d / n / d / t = rate of variation in the number of individuals concerning time in a certain instant.
BIOTIC POTENTIAL is the maximum reproductive potential of a population, the intrinsic properties of organisms to reproduce and survive in order to increase their own number. This can lend itself to different interpretations, i.e., reproductive potential, seed production potential, etc.
Populations can be distributed over a territory following three distribution schemes of base:
- RANDOM DISTRIBUTION
The environment must be theoretically uniform and must not be present tendencies to aggregation
- GROUPED DEPARTMENT
It is the most common form, but if individuals tend to form flocks ad example, here we can talk about random group distribution or regular grouped.
Population regulation mechanisms
In low diversity ecosystems affected by significant physical stress or to those populations subject to irregular or unpredictable extrinsic disturbances, they tend to be regulated by physical factors such as climate, water currents, or physical factors as, e.g., pollution. In highly diverse environments, in favorable environments (few periodic physical stresses, e.g., fire floods, etc.), populations tend to be biologically regulated and, at least in part, they have a self-regulated density. Any limiting or favorable factor that can be placed in two large groups is based on the relationship with the population with which it acts.
Author: Vicki Lezama