Consider the following statements with reference to the ecosystem prod...
- A constant input of solar energy is the basic requirement for any ecosystem to function and sustain. Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis.
- The rate of biomass production is called productivity.
(i) It can be divided into gross primary productivity (GPP) and net primary productivity (NPP).
(ii) Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. Hence statement 1 is correct.
(iii) A considerable amount of GPP is utilised by plants in respiration. Gross primary productivity minus respiration losses (R), is the net primary productivity (NPP).
(iv) GPP – R = NPP o Net primary productivity is the available biomass for the consumption to heterotrophs (herbivores and decomposers). Hence statement 2 is correct. - Secondary productivity is defined as the rate of formation of new organic matter by consumers.
- Primary productivity depends on the plant species inhabiting a particular area. It also depends on a variety of environmental factors, availability of nutrients and photosynthetic capacity of plants. Therefore, it varies in different types of ecosystems. Hence statement 3 is correct.
Consider the following statements with reference to the ecosystem prod...
The correct answer is option 'D', which means all the given statements are correct.
1. Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis:
- Gross primary productivity (GPP) refers to the total amount of organic matter produced by plants through photosynthesis in an ecosystem. It represents the total energy captured by plants from the sun and converted into organic compounds.
- During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose and other organic molecules. This process releases oxygen as a byproduct.
- GPP is a measure of the total energy available in an ecosystem and is expressed in units of energy per unit area per unit time (e.g., grams of organic matter per square meter per year).
2. Net primary productivity is always less than the gross primary productivity:
- Net primary productivity (NPP) refers to the amount of organic matter that remains after plants use some of the energy produced during photosynthesis for their own growth and maintenance (respiration).
- NPP represents the energy available to the consumers (herbivores, carnivores, etc.) in an ecosystem for their growth and reproduction.
- NPP is calculated by subtracting the energy used by plants for respiration (R) from the GPP: NPP = GPP - R.
- Since plants need to use some of the energy they produce for their own metabolic processes, NPP is always less than GPP. The difference between GPP and NPP is called the respiratory loss.
3. Primary productivity depends on the plant species inhabiting a particular area:
- The primary productivity of an ecosystem is influenced by various factors, including climate, nutrient availability, temperature, and sunlight.
- However, the plant species present in an ecosystem play a crucial role in determining its productivity. Different plant species have different photosynthetic efficiencies, growth rates, and nutrient requirements.
- Some plant species are adapted to low-nutrient environments, while others thrive in nutrient-rich areas. These variations in plant species composition can significantly affect the productivity of an ecosystem.
- For example, ecosystems dominated by fast-growing and highly efficient photosynthetic species tend to have higher productivity compared to ecosystems dominated by slower-growing species.
In conclusion, the given statements are all correct. Gross primary productivity represents the total organic matter produced by plants through photosynthesis, net primary productivity is the amount of energy available to consumers after subtracting plant respiration, and primary productivity is influenced by the plant species present in an ecosystem.
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