12th Zoology



What is biodiversity?

Biological diversity means the variability among living organisms from
all sources including terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are parts. It is usually considered at three different levels – genetic diversity, species diversity and ecosystem diversity.

Reasons for Decline of Biodiversity

1. Natural causes of Biodiversity extinction

Studies of the fossil record suggest that more than 99% of all species
ever existed are now extinct. Most of them were gone before humans came on the scene. At the end of Permian period about 250 million years ago, a greater disaster wiped 2/3of all marine species and half of all plant and animal families.

2. Human caused reduction

Natural areas are converted to farms, housing subdivisions, shopping
malls, marinas and industrial centres. For example, when a forest is
cleared, it is not just the trees that are destroyed, but also every other plants and animals that occupy that destroyed ecosystem, either permanently or temporarily also suffers.

Importance Biodiversity conservation?

Biodiversity is the backbone for agriculture, aquaculture, animal husbandry, forestry and a host of other applied branches of biology. Biodiversity is fast becoming the fundamental requirement on which the new industrial developments and innovations are going to be based. Biodiversity will offer in the coming years, new sources of food, medicine and other human requirements.

To save the races of endangered and endemic species the bio
resources should be identified and the hotspots in each country should be given prior importance to conservation. Only then the remaining species at the verge of extinction could be saved.

Consequences of Losing Biodiversity

Many species have already become extinct and we do not know
really what we are losing when we lose species. In future we might lose a keystone species, a species whose role is absolutely vital for the survival of many other species in an ecosystem. For example, the Orchid bees play a vital role in tropical forests by pollinating trees. If they disappear, the eventual fall of that ecosystem is evident. This loss may remove and constrict the natural habitats in which wild species live. Recreational, aesthetic and commercial losses will also be inevitable.

Related Topics in Zoology:

Bio Zoology All Important Topics

  1. Human population and explosion

  2. Population Explosion

  3. Growing Population and Environmental impacts

  4. Global warming – Green house effect

  5. Ozone layer depletion

  6. Prevention and Effect of Ozone depletions

  7. Waste management – Classification

  8. Management of hazardous wastes

  9. Management of non hazardous wastes

  10. Waste water treatment and management

  11. Biodiversity

  12. Conservation of Biodiversity

  13. Characteristics of a Bioreserve

  14. Energy crisis and its environmental impact

  15. Steps to be taken to resolve energy crisis

  16. Environmental impacts of Power Sources

  17. Poverty and environment

  18. Fresh water crisis and management

Unit 6. APPLIED BIOLOGY Topic List Zoology

  1. Livestock and Management

  2. Important cattle breeds and their characteristics

  3. Milch breeds (or) Dairy breeds

  4. Dual purpose breeds & Draught breeds

  5. Exotic breeds of cattle

  6. Common diseases and control in Cattle – Contagious diseases

  7. Non-contagious diseases – Cattle

  8. Techniques adopted in cattle breeding

  9. Poultry Breeds

  10. Farming methods

  11. Poultry byproducts

  12. Fish Pond

  13. Edible Fishes Of Tamilnadu

  14. Medical Lab Techniques – Stethoscope

  15. Sphygmomanometer

  16. Haemocytometer

  17. Urine Sugar analysis

  18. ECG Electrocardiogram

  19. Computed Tomography CT

  20. Endoscopy (Laproscopy) techniques , Artificial Pacemaker

  21. Autoanalyser

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