BIOMES
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A biome is a large region in the biosphere that possesses characteristic physical condition on that support organisms which show adaptations to those condition found there.
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Is a collection of similar ecosystem in a particular region of the earth, it could be a habitat or zone such as desert forest, grassland or water bodies such as ocean, lakes etc.
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- Is a largest terrestrial communication or a largest ecological unit.
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A biome has a specific kind of plants and animal species within a geographical area that has distinct climatic conditions. A biome is a product of physical factors that influence the rainfall, temperature and light.
Example of terrestrial biomes.
A major biomes includes
- Tundra
- Northern coniferous forest or Taiga
- Deciduous forest
- The Mediterranean shrub
- Tropical savannah
- Grassland
- Desert
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Biomes that involve aquatic ecosystems
- Marine environment
- Fresh water environment
- Human population is the most abundant (about 7 billion) which is next to certain species of fishes and insects.
- Human population is widely distributed on earth in almost all climatic conditions from arctic to Antarctica.
- The population differ economically, socially, culturally and color and height in different part of the world.
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The study of trends in human population growth and the prediction of future development is known as demography.
Demography involves the study of various parameters along with number and proportion of different age group, educational requirements training and employment.
Factors affecting patterns of human population.
The human population growth patterns differ in different region of the world due to various factors some of these are discussed below;
- Climatic and Edhapic factor
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The region of extreme heat like deserts or extreme cold like Arctic and Antarctica are less populated.
- Location of natural resources
- Transport facilities.
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Industrial development and education
Demography factor
The birth rate and death rate of a population determine an overall population growth. It varies in different countries.
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Human population growth patterns
- Rate of growth of human population is not uniform in all the countries, the developed countries have stable or negative growth rate (both the birth and death rate are low).
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The developing countries have high birth rate and the population is increasing at an enormous rate.
- Rate of growth differ among different group of people within a country.
- The population of the urban areas is leading to overcrowding and is causing adverse environmental implications.
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POPULATION EXPLOSION AND THEIR CONSEQUENCES
The human population as a whole is growing exponentials having doubled three times in the last three centuries, it now stand at 6 billion and may reach 8 billion by the year 2020.
Most of the increase is due to improved health and technology which have decreased the death rate. The human population faces uncertain feature, although some are optimistic about our ability to expand, earth’s carrying capacity, others are concerned that our increase in numbers may damage the biosphere beyond repair.
Human impact on the ecosystem
Since the development of agriculture and technology on increasing human impact on the environment has occurred. In last two centuries especially wide spread industrialization has lead to potentially damaging environmental pollution.
POLLUTION
- Is the release into the environment of substances or energy in such quantities and for such duration that they cause harm to the people or other organisms or their environment.
- The harmful substances are collectively known as pollutants
- Pollutants destroy the natural quality of the environment.
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Example of pollutants
- Agricultural chemicals such as fertilizers, pesticides and herbicides
- Industrial by products or emissions such as sulphur dioxide, mercury, carbon monoxide, CFC’S lead, cadminium
- Sewage
- Smog
- Oils
- Radiations such as gamma rays, x-ray
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dusts
CONSERVATION
Natural resources:-
- Materials form the natural environment / ecosystem that man can use.
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Types:
- Renewable resources: – Are those which can be replaced within a short period of time after being used e.g. water, wildlife forest e.t.c.
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Non- renewable resources: – Cannot be easily replaced within a short – time e.g. tonsil foils, minerals.
Conservation – retaining the status quo through careful management i.e. preservation of species, habitats and living system from harmful influence of man this avoiding decline and extinction of species and permanent detrimental / degradation to the environment.　
Reasons for conservation
We conserve to maintain world ecosystems by conserving the terrestrial, aquatic & aerial habitats,
- Ethical reasons – cultural, tradition, religious beliefs, political persuasion, shape our attitude toward nature.
- Nature does not exist simply for humans to transform & modify because all living species have a right to coexist with us on earth. Man has no right to cause the extinction or to diminish the quality of life of any organism.
- Custodianship – Man has to pass on to the future generations to all the diversity of life & quality of environment that we inherited.
- Athletic reasons – Humans derive pleasure from pleasant environment & the presence of other living organisms.
- Local national & international organization exist worldwide to promote wildlife contribute to our immediate needs e.g. in forestry many plant species have important medical uses.
- Fisheries from water bodies as direct source of food
- Agriculture – We have to conserve food stocks and soil quality for crops.
- Usage of pollinating insects & beneficial predators in pest control.
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ECOLOGICAL / SCIENTIFIC REASONS
- Maintenance of balanced biochemical cycles to avoid pollution & regulation of the earth’s climatic conditions.
- To avoid deforestation & desertification.
- To avoid loss of vegetation cover this may affect soil erosion leading to accumulation of mud on river beds & costs.
- Reduce extinction of species to retain diversity gene pool (retaining biodiversity)
- To preserve care species that may have generation potential.
- To minimize effects of mining / drilling/ urbanization.
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Measures Taken to conserve the environment / Need for sustainable use of environment resources.
- People should be educated on the importance of our environment by:-
- Encouraging them to plant trees
- Encouraging the use of organic manure & good agricultural practices in agriculture such as terrace farming on hill sides, crop rotation.
- Discouraging harmful traditions such as burning / slash method of farming to clear the land.
- Legislation
- Laws that govern the protection of national parks/ grass kinds & punishments for those who start bush fires
- Laws that protect the endangered species as a means of preventing extinction e.g. rhino
- Some animal species must be regulated to avoid over – population e.g. wild beasts.
- Reduction of pollution e.g. by using lead free petrol, alternate energy source (solar power, ethanol cars) use of bio degradable products, recycle waste such as paper to avoid deforestation, glass & cans water as resource & its sources must be preserved. Government should increase biodiversity by increasing botanical gardens, seed banks & field gene banks.
- Sustainability – exploitation of natural resources & conserving then for future generations.
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WASTE MANAGEMENT
- Avoid excessive use of chemicals such as pesticides and herbicides.
- Encouraging biological control.
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BIOLOGICAL CONTROL
- Is the artificial control of pests & parasites those which compete with human for food or damage the health of humans or livestock by the use of organisms or their products & therefore it is based on predator – prey relationship. The control agent either control the pest by feeding on it (lady bird or aphids, caterpillars larvae of butterflies & moths) are parasitized by bacillus species or by causing disease to the pests e.g. Virus sprays on army worm caterpillar.
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Aim of biological control
- Is to bring the population of the pest down to a tolerable level and not to eradicated by its natural enemy.
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Advantages
- It doesn’t pollute the environment
- It’s easy to apply as it doesn’t involve the use of sophisticated machine
- Its effective through generations as the pest will not develop resistance to the predator as it is with the pesticides & herbicides. Thus time to time application is not important.
- The predator eliminates or feeds / affects the intended organisms or i.e. it is selective.
- It is cheap.
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Disadvantages:
- The beneficial organisms may also be eliminated due to lack of food if it dominates the harmful organisms or pest which may cause / lead to disruption of food chain.
- The predator (agent) may turn into a pest by feeding on other useful organisms instead of feeding on the intended organisms’ e.g. after controlling the pest population it may become a pest itself.
- It’s expensive i.e. involves studying the biology of the pest & the predator & this may take a long time.
- If important agents / predators may fail to survive when the environment of the new country changes.
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Biological control may not be effective if the pest outbreak is high because the agent/ predators are fairly slow to react / to eat to large numbers of pests. The population of pest species left may still be great enough to continue causing damage.
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