Relationship between population size, carrying capacity, and limiting factors is described below.
Explanation:
1. There are four variables which govern changes in population size.
- births
- deaths
- immigration
- emigration
A population gains individuals by birth and immigration and loses individuals by death and emigration.
2. Populations vary in their capacity to grow. The maximum rate at which a population can increase when resources are unlimited and environmental conditions are ideal is termed the population's biotic potential.
3. There are always limits to population growth in nature. Populations cannot grow exponentially indefinitely. Exploding populations always reach a size limit imposed by the shortage of one or more factors such as water, space, and nutrients or by adverse conditions such as disease, drought and temperature extremes.
4. The factors which act jointly to limit a population's growth are termed the environmental resistance. The interplay of biotic potential and density-dependent environmental resistance keeps a population in balance.
5. Carrying Capacity
For a given region, carrying capacity is the maximum number of individuals of a given species that an area's resources can sustain indefinitely without significantly depleting or degrading those resources. Determining the carrying capacities for most organisms is fairly straightforward. For humans carrying capacity is much more complicated. The definition is expanded to include not degrading our cultural and social environments and not harming the physical environment in ways that would adversely affect future generations.
6. Population Impact
Homo sapiens is a species possessing a diversity of individual needs. Thus, sub-populations will have different requirements and different impacts on the environment. For example 100 million vegetarians will have a significantly different environmental impact than 100 million meat-eaters. This can be demonstrated by comparing the affect on water supplies by both sub-populations. About 1000 tons of water are needed to produce 1 ton of grain. Almost 40% of all grain is used in meat and poultry production. Add to this the amount of water that goes into the production of meat, and you can see that meat comsumption places more stress on global water supplies than grain consumption.
Asthma is a chronic disease of the lung that has been increasing at an alarming rate in industrialized countries around the world over the last few decades. Although considerable progress has been made in our understanding of the underlying pathogenesis of the disease, the exact causes of the increasing prevalence are unknown. Studies suggest that most asthma develops in early childhood and that environmental factors present early in life may be crucial in the development of disease. One potential explanation for the recent epidemic referred to as the "hygiene hypothesis" postulates that factors that have resulted in a reduction in exposure to microbial products and/or infections in the western world may be contributing to this rise in disease prevalence. As early life influences are known to play an important role in establishment of asthma, studies have focused on the interface between mother and child that occurs during gestation and through breastfeeding. In this regard, the body of evidence regarding the relationship between breastfeeding and asthma indicates benefit but with the potential for risk. While providing population-level protection from infections and atopy in infancy and early childhood, breastfeeding might also pose an increased risk of atopic asthma among children with asthmatic mothers.
The brain, mind, and body are a single unit which cannot be separated. Any alteration in the brain affects the bodily functions. Any physical condition can cause changes in the mind and the brain.
Research has proven that this mind-body connection is vital for the overall functioning of a human being. The mind and the body are not separate. What affects one affects the other. An imbalance in the body can often find its root in an imbalance in the mind, and vice versa. Given this mind-body connection, it becomes imperative for any wellbeing treatment to address the concerns of both the mind and the body.
DNA damage systematically causes mutations in the genome and changes genetic information.
The pathways of DNA damage are divided into
Exogenous: due to physical factors (such as UV rays and X and gamma ionizing rays) and chemical factors (desaminants, alkylating agents, oxidizing agents, adducts, nucleotide analogues ...).
Endogenous: they are physiological factors (oxidation desamination, depurination ...).
<u>The consequences of these lesions are:
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* Nucleotide substitution (one or more nucleotides)
* Insertion and deletion of nucleotides (one or more nucleotides): addition or deletion of nucleotides within the genome.