Our Environment - 2 - UPSC

Rainfall is not a living organism

The energy transfer in the given scenario can be explained as follows:
1. Grasshopper as a producer:
- Grasshoppers are considered primary producers because they obtain energy directly from the sun through photosynthesis.
- They convert sunlight into chemical energy stored in their bodies.
2. Frog as a primary consumer:
- Frogs are primary consumers because they feed on grasshoppers and other small organisms.
- They obtain energy by consuming the grasshopper, transferring the energy from the grasshopper to themselves.
3. Energy transfer from primary consumer to secondary consumer:
- The frog is then consumed by a secondary consumer, such as a snake or a bird.
- This transfer of energy from the primary consumer (frog) to the secondary consumer represents the flow of energy between trophic levels in a food chain.
Conclusion:
- In the given scenario, the energy transfer is from the primary consumer (frog) to the secondary consumer.
- Therefore, the correct answer is option C: primary consumer to secondary consumer.

Plastic bags are synthetic materials. These are not degraded by bacteria.

The organisms in an ecosystem are related through food requirements. This relationship is called food chain. In option (i) grass is eaten by rabbit, rabbit is consumed by wolf and lion eats wolf. In option (iv) grasshopper eats grass, frog eats grasshopper, snake eats frog and eagle consumes snake. In option (ii) grasshopper is found in terrestrial ecosystems not aquatic ecosystems. In option (iii) there is no herbivore animal to consume grass. Thus, the correct answer is option C.

As per standard 10% rule.

UV rays or ultraviolet rays can affect human health in many ways like causing skin cancer or weakening immune system. Excessive exposure to UV rays can lead to skin cancer because the UV rays cause damage to the DNA in skin cells. 

Concentration of chemicals like insecticides in living system is called biological magnification.

Producers in the Garden Ecosystem

• Insects: Insects are not producers. They are typically classified as consumers in the garden ecosystem as they feed on plants or other organisms.


• Snakes: Snakes are also not producers. They are carnivores and feed on other animals, such as insects, rodents, or birds.


• Grasses: Grasses are the correct answer. They are considered producers in the garden ecosystem as they can produce their own food through the process of photosynthesis. They convert sunlight, water, and carbon dioxide into energy-rich carbohydrates.


• Rabbits: Rabbits, like snakes, are consumers and not producers. They are herbivores and feed on plant material, including grasses, but they do not produce their own food.

Therefore, the correct answer is C: Grasses.

An ecosystem includes both living and non-living organisms.

Autotrophs:
An autotroph is an organism that can produce its own food using light or chemical energy. They are also known as producers because they produce food for other organisms in the ecosystem.
Options:
A: Lion - Heterotroph, as it obtains energy by consuming other organisms.
B: Insect - Heterotroph, as it obtains energy by consuming other organisms.
C: Tree - Autotroph, as it can produce its own food through photosynthesis.
D: Mushroom - Heterotroph, as it obtains energy by decomposing organic matter.
Explanation:
Among the given options, the autotroph is:
- Tree: Trees are autotrophs because they can produce their own food through the process of photosynthesis. They have chlorophyll in their leaves, which allows them to convert sunlight into energy and produce glucose.
Therefore, the correct answer is C: Tree.

Crop field is an artificial ecosystem.

The third trophic level in a food chain is always occupied by carnivores.

Explanation:
The correct logical sequence of a food chain is from the producer to the consumer to the decomposer. Here is a detailed explanation:
A food chain:
- Represents the flow of energy and nutrients from one organism to another in an ecosystem.
- Consists of different trophic levels: producers, consumers, and decomposers.
Producers:
- Are organisms that can produce their own food through photosynthesis or chemosynthesis.
- Examples include green plants, algae, and some bacteria.
- They convert sunlight or inorganic substances into organic matter.
Consumers:
- Are organisms that obtain their energy and nutrients by consuming other organisms.
- They cannot produce their own food.
- Examples include herbivores, carnivores, and omnivores.
Decomposers:
- Are organisms that break down dead organic matter and waste products.
- They release nutrients back into the ecosystem.
- Examples include fungi and bacteria.
Logical sequence of food chain:
The correct logical sequence of a food chain is:
1. Producers: They are at the base of the food chain as they produce their own food.
2. Consumers: They obtain their energy by consuming producers or other consumers.
3. Decomposers: They break down dead organic matter and waste products, recycling nutrients in the ecosystem.
Conclusion:
The correct logical sequence of a food chain is producer → consumer → decomposer. This sequence represents the flow of energy and nutrients in an ecosystem, starting from the producers, passing through the consumers, and ending with the decomposers.

According to 10% rule, energy available at producer level will be 5 x 10 x 10 x 10 = 5000 kJ.

There are many food chains which are interconnected to form the food web and so one organism can feed at different trophic levels in the different food chain. There is a 0gradual decrease in the energy of the increasing trophic levels due to the loss of energy with each transfer. The producers are the organisms which can synthesize food and the organisms which feed on the other sources are known as consumers. The detrivores are the organisms which feed on the dead matter of the organisms which belong to all the trophic levels. 

Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the food web.

Why are green plants usually the first link in any food chain?

Green plants are usually the first link in any food chain because:

• Capacity to synthesize food: Green plants are the primary producers in an ecosystem. They have the ability to synthesize their food through a process called photosynthesis, using sunlight, water, and carbon dioxide. This allows them to convert solar energy into chemical energy in the form of glucose.



• Provide energy: Green plants serve as a source of energy for other organisms in the food chain. They convert sunlight energy into organic matter, which is consumed by herbivores.



• Abundance: Green plants are widely distributed and abundant in most ecosystems. They can be found in various habitats, including terrestrial and aquatic environments. Their abundance ensures a stable and continuous food supply for other organisms.



• Fixed in one place: Unlike animals, green plants are fixed in one place due to their root systems. This allows them to establish a stable base for the food chain, as they act as a foundation for the whole ecosystem.

Overall, green plants hold a crucial role in the food chain as they provide energy, are widely distributed, have the capacity to synthesize food, and form the primary link in the transfer of energy through the ecosystem.

Depletion of ozone layer is mainly due to chlorofluorocarbon compounds.

• A food chain comprising birds, green plants, fish and man.
• Food chain in ecology, the sequence of transfers of matter and energy in the form of food from one organism to another organism.
• Food chains intervined locally into a food web because most organisms consume more than one type of animal or plant.
• Each level of a food chain represents a different trophic level.
• Humans are to be present at the top of the food chain because they eat all kinds of plants and animals.
• The human food chain starts with plants.
• Humans are dominant consumers.
• They affect food webs through energy production and agriculture, pollution, habitat destruction, overfishing and hunting it affect both soil and aquatic ecosystem.

All green plants and few blue-green algae which can produce food by photosynthesis are called the producers.