- List the different attributes that a population has and not an individual organism.
- What is population density? Explain any three different ways the population density can be measured, with the help of an example each.
OR
“It is often said that the pyramid of energy is always upright. On the other hand, the pyramid of biomass can be both upright and inverted.”
Explain with the help of examples and sketches.
- List the different attributes that a population has and not an individual organism.
- What is population density? Explain any three different ways the population density can be measured, with the help of an example each.
OR
“It is often said that the pyramid of energy is always upright. On the other hand, the pyramid of biomass can be both upright and inverted.”
Explain with the help of examples and sketches.
Natality, mortality, population density, population growth, population dispersal, sex ratio and age distribution are the different attributes which a population has but not an individual organism.
- Population density: It is defined as the number of individuals present in a unit area at a given time. The different ways by which population density can be measured are
Population density can be measured by counting all the individuals in a region, but if the population is large, then counting may not be possible. Example: Counting Siberian cranes at Bharatpur wetlands.
- Percent cover or biomass is also used to measure the population density in huge populations. Example: Dense laboratory culture of bacteria in a Petri dish can be measured only by biomass.
- Relative density is also used to measure population density. Example: The number of fish caught per trap is used to measure its total population density in a lake.
OR
Pyramid of energy is a graphical representation of amount of accumulated energy per unit area in different trophic levels of a food chain. An energy pyramid is always upright because there is a gradual decrease in energy at successive trophic levels. This happens according to the 10% law of energy transfer, where only 10% of the total energy is transferred from one trophic level to another. The energy is the highest at the producer level, and it gradually decreases on moving from herbivores to carnivores.
Natality, mortality, population density, population growth, population dispersal, sex ratio and age distribution are the different attributes which a population has but not an individual organism.
- Population density: It is defined as the number of individuals present in a unit area at a given time. The different ways by which population density can be measured are
Population density can be measured by counting all the individuals in a region, but if the population is large, then counting may not be possible. Example: Counting Siberian cranes at Bharatpur wetlands.
- Percent cover or biomass is also used to measure the population density in huge populations. Example: Dense laboratory culture of bacteria in a Petri dish can be measured only by biomass.
- Relative density is also used to measure population density. Example: The number of fish caught per trap is used to measure its total population density in a lake.
OR
Pyramid of energy is a graphical representation of amount of accumulated energy per unit area in different trophic levels of a food chain. An energy pyramid is always upright because there is a gradual decrease in energy at successive trophic levels. This happens according to the 10% law of energy transfer, where only 10% of the total energy is transferred from one trophic level to another. The energy is the highest at the producer level, and it gradually decreases on moving from herbivores to carnivores.
