2006 | Zoology for IAS, Indian civil services

Medical Entomology

Many insects transmit diseases in humans or suck blood or cause nuisance and irritation and hence are undesirable and need eradication. The following insects are included in this section.

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Insect pests of forest & orchards

Large trees in forests, plantations and orchards are attacked by different types of insects. Generally in forests, insect populations are maintained below the damage levels by their natural enemies. But sometimes pest outbreaks do take place causing immense damage to trees and timber. In orchards pest control strategies have to be in place to deal with the pest outbreaks. The following insects attack large trees in forests and orchards.

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Termites
Locusts

Insect Pests of Stored Grains

When harvested produce is stored in houses, godowns and warehouses, it is attacked by a variety of insects that specialize in thriving under enclosed conditions. Although moisture, fungus, rodents and birds also cause damage to the stored grains, insects are considered to be the chief destroyers of harvested grains. The following insect pests are included in this section.

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Evolution

Biological phenomena are so complex that they can be logically explained only in the light of evolution. Evolution therefore has to be brought into picture while studying any aspect of zoology, namely, anatomy, embryology, cytology or physiology. The fact that animals and plants change and do not remain static during the course of time is the backbone of evolutionary reasoning. Dobzhansky’s view that nothing makes sense in biology except in the light of evolution outlines the importance of this branch of science. The word evolution simply means a change with time, and organic evolution means change in plants and animals from generation to generation, which Darwin called, “descent with modification”.

Evolution is the outcome of interaction of organisms with their environment. As animals try to adapt to the changing environment, adaptive structures arise by gradual change in the existing organs, which over a period of time accumulate to form large anatomical changes that we call marvels of nature.

Evolutionary changes in reality occur by chance or as short term advantages of variations. Adaptations do not evolve because they benefit species but evolution produces patterns of variability from which some animals might derive benefits while others not.

Natural selection is the executing arm of evolution which thrives on excessive reproduction and genetic diversity caused by sexual reproduction and mutations. Therefore, genetic composition of a population changes with the passage of each generation and all organisms existing today are modified descendants of the ancestors that existed sometime in the past.

The following chapters are included in this section. Click on the title to open.

Origin of life

Evidences of evolution

Natural selection

Types of selection

Hardy-Weinberg’s Law

Sewall-Wright Effect

Variations

Isolation

Speciation

Fossils and fossilization

Evolution of horse

Evolution of elephant

Evolution of Man

Geological Eras

Charles Darwin

Anagenesis & Cladogenesis

Balanced Polymorphism

Books on Evolution

Evolutionary thoughts

Darwinian Fitness

Kin Selection

Micro- Macro- & Megaevolution

Molecular Evolution

Parallel Evolution

Selection Coefficient

Character Displacement

Evolutionary Rates

Speed of Evolution

The Riddle of Human Origin

The mystery of mass extinctions

Origin & Evolution of Amphibia

Origin & Evolution of Reptilia

Origin & Evolution of Birds

Origin & Evolution of Mammals

Origin & Evolution of Cow

General Entomology

Entomology is the science of studying insects that constitute about 75% of the animal kingdom as far as the number of species is concerned. They are ubiquitous and highly diversified creatures and hence are an interesting subject of study.

The following topics appear in this section. Click on the title to open.

The Wildlife of India

Wildlife involves the study of wild undomesticated animals and plants living in their natural habitats and their ecological interactions. Due to the destruction of forests, a large number of animals and plants have become endangered and their conservation has become a matter of utmost importance. We have to spread awareness that protection of wildlife is necessary for ensuring our own survival on this planet.

The following chapters are included in this section.

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Books on wildlife

Wildlife Management and conservation

Wildlife sanctuaries

National Parks

Biosphere reserves

Project Tiger

Camels of the world

Fish Wildlife

Amphibian Wildlife

Reptilian Wildlife

Avian Wildlife

Mammalian Wildlife

The Apes

Crocodiles, Alligators and Gharials

Sphenodon, The Living Fossil

Applied Entomology

Applied or economic Entomology deals with both destructive and useful insects, namely, productive insects such as honey bee and silk worm, whose products can be directly used by man. Pollinators such as bees, wasps and butterflies, and parasites that keep in check the noxious pests of agriculture, also benefit humans. Control of pests of agriculture, forestry, orchards, livestock as well as vectors of diseases such as housefly, mosquito, flea etc. also comes under applied entomology.