The concept that population tends to increase geometrically while food supply increases arithmetically was put forward by
Stuart Mill
Adam Smith
Charles Darwin
Thomas Malthus
Which one of the following statement is correct?
Extensive use of chemical fertilizers may lead to eutrophication of nearby water bodies.
Both azotobacter and rhizobium fix atmospheric nitrogen in root nodules of plants.
Cyanobacteria such as anabaena and nostoc are important mobilizers of phosphates and potassium for plant nutrition in soil.
At present it is not possible to grow maize without chemical fertilizers.
Which of the following plants are used as green manure in crop fields and in sandy soils?
Saccharum munja and Lantana camara
Dichanthium annulatum and Azolla nilotica
Crotalaria juncea and Alhagi comelorum
Calotropis procera and Phyllanthus niruri
In a random mating population in equilibrium, which of the following brings about a change in gene frequency in non-directional manner?
Selection
Migration
Mutation
Random drift
One of the major difficulties in the biological control of insect pests is the
Practical difficulty of introducing the predator to specific areas
Method is less effective as compared with the use of insecticides
Predator does not always survive when transferred to a new environment
The predator develops a preference to other diets and may itself become a pest
Certain characteristic demographic features of developing countries are
High fertility, low or rapidly falling mortality rate, rapid population growth and a very young age distribution
High fertility, high density, rapidly rising mortality rate and a very young age distribution
High infant mortality, low fertility, uneven population growth and a very young age distribution
High mortality, high density, uneven population growth and a very old age distribution
What is agent orange?
A biodegradable insecticide
A weedicide containing dioxin
Colour used in fluorescent lamp
A hazardous chemical used in luminous paints
Geometric representation of age structure is a characteristic of
Biotic community
Population
Landscape
Ecosystem
Farmers have reported over 50% higher yields of rice by using which of the following biofertilizer?
Mycorrhiza
Azolla pinnata
Cyanobacteria
Legume-Rhizobium symbiosis
Two opposite forces operate in the growth and development of every population. One of them is related to the ability to reproduce at a given rate. The force opposing to it is called
Biotic control
Mortality
Fecundity
Environmental resistance
