All questions of Ecosystem for NEET Exam

Of the total solar energy, only 50%is PAR( photosynthetically active radiation) of which plants utilise only 2-10% fr photosynthesis. thus,op B.

<b>Introduction</b>
Net primary productivity (NPP) is the amount of energy that is converted into organic matter through photosynthesis in plants, minus the energy that is used by the plants for their own respiration. It is an important measure of the productivity and biomass production in an ecosystem. In this question, we are asked to determine which ecosystem type has the highest annual NPP among the given options.

<b>Explanation</b>
To determine which ecosystem type has the highest annual NPP, we need to consider the characteristics of each ecosystem and how they influence primary productivity.

<b>Tropical deciduous forest</b>
- Tropical deciduous forests are found in regions with distinct wet and dry seasons.
- These forests have a high diversity of plant species.
- During the wet season, these forests experience high rates of photosynthesis and growth.
- However, during the dry season, many of the trees shed their leaves and the productivity decreases.
- Therefore, the annual NPP of tropical deciduous forests is relatively lower compared to other ecosystem types.

<b>Temperate evergreen forest</b>
- Temperate evergreen forests are found in regions with moderate temperatures and abundant rainfall throughout the year.
- These forests are dominated by evergreen trees that maintain their leaves year-round.
- The constant availability of water and sunlight allows for continuous photosynthesis and growth.
- Therefore, temperate evergreen forests have a relatively high annual NPP.

<b>Temperate deciduous forest</b>
- Temperate deciduous forests are found in regions with distinct seasons, including a cold winter.
- These forests are characterized by deciduous trees that lose their leaves during the winter.
- The productivity of these forests is highest during the growing season when the trees have leaves.
- However, the productivity decreases during the winter when the trees are bare.
- As a result, the annual NPP of temperate deciduous forests is lower compared to temperate evergreen forests.

<b>Tropical rainforest</b>
- Tropical rainforests are found in regions near the equator with consistently high temperatures and abundant rainfall.
- These forests have the highest biodiversity and are dominated by tall, evergreen trees.
- The combination of high temperature, abundant water, and sunlight results in high rates of photosynthesis and growth throughout the year.
- Therefore, tropical rainforests have the highest annual NPP among the given options.

<b>Conclusion</b>
Among the given options, the tropical rainforest has the highest annual net primary productivity due to its consistently high temperature, abundant rainfall, and high biodiversity.

Understanding the Statements
The two statements pertain to the process of decomposition in ecological systems. Let's analyze each statement:
Statement I: The rate of decomposition is not related to chemical composition of detritus and climatic factors.
- This statement is False.
- Decomposition is significantly influenced by the chemical composition of detritus (organic matter) and various climatic factors such as temperature, moisture, and humidity.
- For instance, materials rich in cellulose decompose faster than those rich in lignin due to their chemical structure.
Statement II: In a particular climatic condition, decomposition rate is faster if detritus is rich in lignin and chitin.
- This statement is also False.
- Lignin is known to be more resistant to decomposition compared to other organic compounds. Chitin, found in the exoskeletons of arthropods, also decomposes slowly.
- Therefore, detritus that is rich in these compounds typically decomposes at a slower rate, contrary to what is stated.
Conclusion
Since both statements are incorrect, the correct answer is option b) Both Statement I and Statement II are False.
Understanding the dynamics of decomposition is crucial in ecology, as it affects nutrient cycling and energy flow within ecosystems.

Understanding Gross Primary Productivity (GPP) and Net Primary Productivity (NPP)
Gross Primary Productivity (GPP) refers to the total amount of organic matter, or biomass, produced by photosynthetic organisms in an ecosystem within a specific time frame. This includes all the energy captured by plants through photosynthesis.
Net Primary Productivity (NPP), on the other hand, is the energy or biomass available to the next trophic levels, which is calculated by subtracting the energy used by plants for respiration from GPP.
Key Differences Between GPP and NPP:
- GPP represents total energy capture.
- NPP represents the energy available for consumption by herbivores and decomposers.
Why GPP is Always Greater than NPP:
- Respiration Losses: A portion of the energy captured by plants is utilized for their own metabolic processes, such as respiration. This energy loss means that NPP will always be less than GPP.
- Formula Representation: Mathematically, NPP = GPP - Respiration. Since respiration is always a positive value, NPP is always less than GPP.
- Ecological Implications: The difference between GPP and NPP highlights how much energy is available for the food web. A higher GPP indicates a productive ecosystem, but the NPP is crucial for supporting herbivores and, subsequently, carnivores.
Conclusion:
In summary, option 'D' is correct because Gross Primary Productivity is always more than Net Primary Productivity due to the energy lost during respiration processes in plants. Understanding this relationship is essential for grasping ecosystem productivity dynamics in ecological studies.

Ecological Pyramids

Ecological pyramids are graphical representations of the trophic structure and energy flow within an ecosystem. They provide a visual representation of the relative amounts of energy or biomass at each trophic level in an ecosystem.

There are three types of ecological pyramids:
1. Pyramid of numbers: It represents the number of individuals at each trophic level.
2. Pyramid of biomass: It represents the total dry weight of organisms at each trophic level.
3. Pyramid of energy: It represents the total amount of energy present at each trophic level.

Construction of Ecological Pyramids

To construct ecological pyramids, various factors and parameters are taken into consideration. These include:
- Number of individuals
- Rate of energy flow
- Fresh weight
- Dry weight

Explanation of the Answer

The answer to the given question is option 'C' - Fresh weight. Fresh weight is not used for the construction of ecological pyramids.

Reasoning

Fresh weight refers to the weight of an organism or its parts when they are freshly harvested or collected. However, fresh weight is not a reliable measure for constructing ecological pyramids because it includes the weight of water content in the organism. Since water content can vary greatly between organisms and can change over time, it does not provide an accurate representation of the biomass or energy present at each trophic level.

Importance of Dry Weight

Dry weight, on the other hand, is the weight of an organism or its parts after all the water content has been removed. It provides a more accurate measure of the biomass and energy present in an organism. Dry weight is used to construct the pyramid of biomass, which represents the total dry weight of organisms at each trophic level in an ecosystem.

Conclusion

In summary, the construction of ecological pyramids involves considering factors such as the number of individuals, rate of energy flow, and dry weight. Fresh weight, which includes the weight of water content, is not used for constructing ecological pyramids as it does not provide an accurate representation of the biomass or energy present at each trophic level.

, b, c, and d) below and determine which one is most likely to be true based on the given evidence:

a) All birds have feathers.
b) Penguins are birds.
c) Penguins are flightless.
d) All flightless animals are penguins.

Based on the evidence, the most likely true statement is:

c) Penguins are flightless.

Grassland Ecosystem and Production

Grassland ecosystems are characterized by a dominant vegetation of grasses and herbaceous plants. These ecosystems can be found in various regions around the world, including prairies, savannas, and steppes. They are known for their high productivity and support a diverse range of organisms.

Production in Ecosystems

Production in ecosystems refers to the process of converting solar energy into organic matter through photosynthesis. It can be divided into three categories: gross production (GP), net production (NP), and tertiary production.

1. Gross Production (GP):
Gross production (GP) is the total amount of organic matter produced by plants through photosynthesis in a given area within a specific time period. It represents the total energy captured by plants from the sun. GP includes both the energy used by plants for their own growth and maintenance (respiration) and the energy available for consumption by other organisms.

2. Net Production (NP):
Net production (NP) is the energy stored in plants' biomass that is available for consumption by herbivores. It is calculated by subtracting the energy lost through respiration (used for plant growth and maintenance) from the gross production. NP represents the energy available to support primary consumers in the food chain.

3. Tertiary Production:
Tertiary production refers to the energy stored in the biomass of higher trophic levels, such as carnivores and top predators. It represents the energy available to support secondary consumers and is derived from the consumption of primary consumers (herbivores).

Highest Value in a Grassland Ecosystem

In a grassland ecosystem, the highest value is expected for gross production (GP). This is because grasslands are highly productive ecosystems due to the abundance of grasses and herbaceous plants. These plants have adapted to a rapid growth strategy, allowing them to capture and utilize a significant amount of solar energy.

The high GP value indicates the total energy captured by plants through photosynthesis. It includes the energy used for plant growth and maintenance as well as the energy available for consumption by herbivores. Therefore, GP provides an estimate of the total energy available to support primary consumers and the subsequent trophic levels in the grassland ecosystem.

On the other hand, net production (NP) represents the energy available for consumption by herbivores after deducting the energy used for plant growth and maintenance. Tertiary production represents the energy stored in the biomass of higher trophic levels. While NP and tertiary production are important measures in the ecosystem, they are expected to have lower values compared to GP in a grassland ecosystem.

In conclusion, gross production (GP) is expected to have the highest value (gm/m2/yr) in a grassland ecosystem due to the high productivity of grasses and herbaceous plants in capturing solar energy through photosynthesis.