Free Man and His Environment MCQs with Answers

111. Geometric representation of age structure is a characteristic of:

• A. Population
• B. Landscape
• C. Ecosystem
• D. Biotic community

Explanation: Population has several characteristics or attributes which are a function of the whole group and not of an individual. Age distribution is one of them that is the number or the percentage of individuals in a population in different age groups. This is represented geometrically in the form of age pyramid.

112. The population of an insect species shows an explosive increase in numbers during rainy season followed by its disappearance at the end of the season. What does this show?

• A. The food plants mature and die at the end of the rainy season.
• B. Its population growth curve is of J­-type.
• C. The population of its predators increases enormously
• D. S-­shaped or sigmoid growth of this insect.

Explanation: The J-shape of growth pattern can be easily observed in algae blooms, some insects, annual plants and the lemmings of Tundra. In the beginning, the density of the population increases rapidly in compound interest fashion and then stops abruptly as the environmental resistance or other limiting factors become effective. These factors may be food, space, seasonal (frost, excessive rain etc.) or the termination of the reproduction session.In the rainy season, there is an abundance of resources such as water, food, and suitable breeding sites for the insect species. This abundance allows the population to grow rapidly. With favorable conditions, the insect population experiences a surge in reproduction and population growth. More individuals are born, and they can successfully develop into adults. As the rainy season ends, resource availability starts to decline. Water sources may dry up, food becomes scarcer, and the breeding conditions become less favorable. This leads to increased competition for limited resources.

113. If the mean and the median pertaining to a certain character of a population are of the same value, the following is most likely to occur:

• A. A bi­-modal distribution
• B. A T­-shaped curve
• C. A skewed curve
• D. A normal distribution.

Explanation: When the mean and median are the same, it indicates that the data is evenly distributed around the central value. In a normal distribution, for example, the mean, median, and mode (most common value) are all equal and located at the center of the distribution.

114. A high density of elephant population in an area can result in:

• A. Intraspecific competition
• B. Interspecific competition
• C. Predation on one another
• D. Mutualism

Explanation: Competition is rivalry for obtaining the same resource. Competition is of two types, intraspecific and interspecific. Intraspecific competition is the competition amongst members of the same species for a common resource. It may be for food, space, and mate. So if the density of elephant population in an area increases, it will lead to intraspecific competition. This will lead to the establishment of territories in elephants which will result in pushing out of the extra number securing shelter, mate and food for the rest.

115. Niche overlap indicates:

• A. Mutualism between two species.
• B. Active cooperation between two species.
• C. Two different parasites on the same host.
• D. Sharing of one or more resources between the two species.

Explanation: Niche/ecological niche is the specific part of a habitat occupied by individuals of a species which is circumscribed by its range of tolerance, range of movement, microclimate, type of food and its availability, shelter, type of predator and timing of activity. A habitat has several ecological niches and supports a number of species. An ecological niche is used by a single species. Two or more species cannot use the same niche despite having a mutualistic association. Organisms or populations in competition have a niche overlap of a limited resource for which they compete. Both owl and cat feed on shrews and mice. They occupy the same niche because of being ecological equivalents even though their habitats are different.

116. About 15% of world's freshwater is contained in

• A. Polar ice
• B. Glaciers and mountains
• C. Antarctica
• D. Greenland

Explanation: Nearly about 97% of the earth's water is saline in the oceans and seas. 3% of the earth's water is locked up on the polar ice caps. 85% of the frozen freshwater is in the Antarctic ice cap, 15% of the frozen freshwater is in the northern polar ice cap and glaciers.

117. At which latitude does heat gain through insolation approximately equal heat loss through terrestrial radiation?

• A. 22 1/2° North and South
• B. 40° North and South
• C. 42 1/2° North and South
• D. 66° North and South

Explanation: Earth does not receive equal radiation at all points. The East-West rotation of the earth provides equal exposure to sunlight but latitude and dispersion do affect the amount of radiation received. The poles receive far less radiation than the equator. This uneven heating is called differential insolation. At 40º North and South, approximately the heat gain is equal to heat loss through terrestrial radiation.

118. What is a keystone species?

• A. A species that makes up only a small proportion of the total biomass of a community, yet has a huge impact on the community's organization and survival.
• B. A common species that has plenty of biomass, yet has a fairly low impact on the community's organization.
• C. A rare species that has minimal impact on the biomass and on other species in the community.
• D. A dominant species that constitutes a large proportion of the biomass and which affects many other species.

Explanation: Keystone species are those species that have a significant and disproportionately large influence on the community structure and characteristics. It has often a considerably low abundance and biomass as compared to dominant species. Removal of such species causes serious disruption in the structure and function of a community.

119. In which one of the following pairs is the specific characteristic of a soil not correctly matched?

• A. Laterite ­- contains aluminium compound
• B. Terra rosa - most suitable for roses
• C. Chernozems - richest soil in the world
• D. black soil - rich in calcium carbonate

Explanation: Black soil forms the largest group. Black soils, also known as regosols or black clay soils, are typically not rich in calcium carbonate. Instead, these soils are characterized by their high clay content, dark color, and rich organic matter. Black soils are often found in various parts of the world and are known for their fertility and suitability for agriculture. It is developed mainly on the Deccan traps of Maharashtra, Madhya Pradesh and Kathiawar. Because of its hydrology and climatic conditions of the environment, the medium and deep black soils are very suitable for cotton cultivation.

120. In which one of the following habitats does the diurnal temperature of soil surface vary most?

• A. Shrub land
• B. Forest
• C. Desert
• D. Grassland

Explanation: Deserts are places where the diurnal temperatures vary greatly. It is extremely hot during the day time and very cold at night. This change in temperature also affects the temperature condition of the soil.