Chapter 14: Ecosystem

Ans: Only 10% of the total energy ingested by a species at one trophic level is accessible to the organism at the next trophic level, as per the 10% rule. As a result, only 10% of the energy a producer turns into biomass is available to the primary consumer. Likewise, the secondary consumer has access to only 10% of the energy utilised by the first consumer. Due to the similar reason, higher trophic level species have less energy available.

Ans: The number of trophic levels in every ecosystem can reach a maximum of five, in which case the food chain would appear like this:

Producer → Primary Consumer → Secondary Consumer → Tertiary consumer → Quaternary Consumer

Assume that the producer is able to capture 100 units of energy. The producer will use 90 of these units, while the primary consumer will have access to 10 of them. Finally, the quaternary consumer will have access to only 0.001 units, which is an insignificant amount of energy. As a result, no ecosystem can support additional trophic levels.

Ans: Aquariums are man-made ecosystems with their own set of constraints. Producers cannot have a limitless supply of inorganic materials in the confined space of an aquarium. A significant number of producers is required to support even a small number of consumers that is not achievable in a tiny aquarium. Food must be provided for the aquarium's fish, and the aquarium must be cleaned on a regular basis. Because an aquarium isn't self-sustaining, it can't be considered a complete ecosystem.

Ans: Decomposition is primarily an oxygen-dependent procedure. This also necessitates the use of ambient temperature and moisture. Decomposition is accelerated when debris is high in nitrogen and water-soluble compounds. Each of these conditions can be found in a tropical climate. As a result, decomposition occurs more quickly in the tropics.

Ans: The two actions that disrupt the carbon cycle are as follows:

(a) Forest clearing: Less green cover slows carbonification, causing the carbon cycle to be disrupted.

(b) Burning Fossil Fuels: Burning fossil fuels releases carbon into the atmosphere, increasing the percentage of carbon dioxide in the atmosphere. It also has an impact on the carbon cycle.

Ans: At a specific trophic level, about 90% of the energy ingested by an organism is wasted as heat energy. Just 10% is left over for the organism at the next trophic level. By the time it reaches the highest trophic level, the energy accessible is a miniscule fraction of the energy converted by the producer. As a consequence, energy transmission through various trophic levels is non-cyclic and unidirectional.

Ans: Productivity, decomposition, energy flow, and nutrient cycling are all necessary components of any ecosystem. Plants and animals both contribute to productivity. While some microorganisms have a role in productivity, like algae and chemosynthetic bacteria, others, like algae and chemosynthetic bacteria, are autotrophs. Heterotrophic microorganisms make up the majority of the population. Parasitic bacteria get their nourishment from the host they live in. Saprotrophs are a type of microorganism that feeds on other bacteria. They eat detritus and are hence a vital part of the detritus food chain.

Ans: Tigers are tertiary consumers, which means they are at the top of the forest food chain. The regulation of secondary and primary consumer population growth is aided by a tertiary consumer. If all tigers are eliminated, there will be no animal remaining to manage the herbivore population. Producers will quickly become exhausted as a result of this.

In the absence of producers, herbivores would eventually starve to death. This will completely devastate the ecology.

Ans: It is known that only 10% of the energy consumed at one trophic level can be used at the next. At the primary consumer level, 10 kg of deer meat equals 10 kg of biomass. 90% of it is absorbed by the deer for its own consumption. The lion will have access to the leftover 10%, or 1 kilogramme. As a result, it is correct to declare that 10 kg of deer meat equals 1 kg of lion meat.

Ans: The biomass generated per unit area by photosynthesis over time is referred to as primary productivity. It is the quantity of biomass produced by green trousers in a given habitat in simple terms. The number of plants differs from one ecosystem to the next. The number of plants in tropical rainforests is higher than in deserts. As a result, primary productivity in tropical rainforests would be substantially higher than in deserts. This demonstrates that primary productivity differs by ecology.