Eco System

Marine ecosystems encompass about 71% of the Earth's surface, holding approximately 97% of the world's water. These ecosystems contribute significantly to the planet's total net primary production, accounting for 32% of it. Depending on factors such as water depth and shoreline characteristics, marine ecosystems can be categorized into various zones. The benthic zone, which encompasses substrates beneath the water's surface, provides habitat for numerous invertebrate species. Marine ecosystems host diverse classes of organisms, including brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Additionally, the fishing industry relies heavily on marine ecosystems, as they serve as the primary source of commercial seafood harvested from wild populations.

So, the correct option is (C): Benthonic and brown algae

These three crops, wheat, rice, and maize (corn), are among the world's most widely cultivated and consumed staple crops, providing a significant portion of the world's food supply.

So, the correct option is (A): wheat, rice, and maize

Fresh weight is not commonly used for the construction of ecological pyramids. Ecological pyramids typically use measures such as dry weight (biomass), the number of individuals, or the rate of energy flow (productivity) to represent the trophic levels in an ecosystem. Fresh weight includes the weight of water content in organisms, which can vary greatly and is not as consistent or informative for ecological studies as dry weight.

So, the correct option is (D): Fresh Weight

Stratification is the vertical distribution of different species occupying different levels in a biotic community. It is formation of vertical layers where vegetation is dense, i.e. 5-7 strata (layer) in tropical rain forests with emergent tall trees, canopy trees, shrub layer below tree layer, bottom layer of herbs and grass at ground level. Zonation is the horizontal categorization of biomass into zones based on their distribution or arrangement in habitat as determined by environmental factors, e.g. altitude, latitude, temperature, biotic factors, etc.

So, the correct option is (D): stratification.

To understand the given statements and determine the correct answer, let's analyze each statement individually:

Statement I: Decomposition is a process in which the detritus is degraded into simpler substances by microbes.

This statement is accurate because decomposition involves the breakdown of organic matter (detritus) by microorganisms, resulting in simpler substances. Thus, Statement I is correct.

Statement II: Decomposition is faster if the detritus is rich in lignin and chitin.

This statement is incorrect. Lignin and chitin are complex biopolymers that are difficult for decomposers to break down. When detritus is rich in lignin and chitin, decomposition generally slows down, as these substances require specialized enzymes and conditions for decomposition.

Thus, the correct evaluation is that Statement I is correct, while Statement II is incorrect. Therefore, the correct answer is: "Statement I is correct but Statement II is incorrect."

The problem requires an evaluation of two given statements based on the principles of ecology.

Statement I: According to Gause’s ‘Competitive Exclusion Principle’, no two species that make their living in the same way can coexist indefinitely in an unchanging environment. If two species occupy the same niche, the inferior competitor will be eliminated. This makes Statement I correct.

Statement II: This statement suggests that carnivores face more severe competition than herbivores. Generally, competition affects each organism type differently depending on the specific ecological context rather than universally impacting carnivores more than herbivores. Therefore, Statement II is false.

In conclusion, the correct answer is: Statement I is correct Statement II is false.

The given equation is:

GPP - R = NPP

Where:

• GPP is Gross Primary Productivity, which measures the total amount of energy produced by photosynthesis in an ecosystem.
• NPP is Net Primary Productivity, representing the energy available to consumers after subtracting the energy used by producers for respiration.
• R represents the variable we are defining.

The equation can be rewritten as:

NPP = GPP - R

Solving for R, we find that it represents the energy lost through processes such as metabolism and maintenance in producers, allowing us to conclude that R is:

Respiratory loss

Therefore, the correct option is Respiratory loss.

In biology, detritivores play a crucial role in the ecosystem by processing detritus, which is dead organic matter, into smaller particles. This essential function helps enhance the decomposition process and recycling of nutrients. The mechanism whereby detritivores such as earthworms, millipedes, or certain beetles break down detritus into smaller fragments is specifically known as Fragmentation. Although similar-sounding processes like catabolism, humification, and decomposition are also part of nutrient cycling, they differ in their specific functions:

• Catabolism involves the breakdown of complex molecules into simpler ones, usually releasing energy. It's more applicable to cellular metabolic processes rather than ecosystem nutrient cycling.
• Humification is the process through which humus is formed, involving the decomposition of organic matter to a stable organic substance in soil.
• Decomposition is the overall biological breakdown of organic matter into simpler organic or inorganic substances, driven by both microbial activity and physical breakdown by detritivores.

Thus, the correct term for the detritivores' action of breaking down detritus into smaller particles is Fragmentation.

To identify the correct statements, let's analyze each one:

1. Statement A: Detrivores perform fragmentation.
   Detrivores are organisms that feed on dead organic matter. Fragmentation is the process of breaking down large pieces into smaller ones, which is indeed carried out by detrivores. Thus, this statement is correct.
2. Statement B: The humus is further degraded by some microbes during mineralization.
   Mineralization is the process where organic matter is converted into inorganic substances by microbial action. Hence, humus being degraded by microbes fits this description. Therefore, this statement is correct.
3. Statement C: Water soluble inorganic nutrients go down into the soil and get precipitated by a process called leaching.
   Leaching is the washing away of nutrients from the soil by water. It typically involves the movement of dissolved substances. So this statement correctly describes the leaching process. Thus, this statement is correct.
4. Statement D: The detritus food chain begins with living organisms.
   The detritus food chain starts with dead organic matter, not living organisms. Therefore, this statement is incorrect.
5. Statement E: Earthworms break down detritus into smaller particles by a process called catabolism.
   Catabolism is a metabolic process involving the breakdown of complex molecules within living organisms. However, earthworms break down detritus physically, which is not catabolism. Therefore, this statement is incorrect.

Based on the analysis, the correct statements are A, B, C.