Biogeography & Ecosystems

Hedgehogs: Hedgehogs are small mammals have a unique defense mechanism where they roll up into a tight ball, using their sharp spines as a form of protection against predators. Marmots: Marmots do not roll up to protect themselves. Instead, they typically rely on burrows and their ability to give warning calls to avoid predators. Pangolins: Similar to hedgehogs, pangolins also roll up into a ball when threatened. They use their tough keratin scales as armor to protect their vulnerable parts.

Detritivores: These are organisms that feed on dead and decaying organic matter (detritus). Earthworms: They are classic detritivores, breaking down organic matter in soil and aiding in decomposition. Millipedes: They feed on decaying leaves and other organic debris on the forest floor. Woodlice: These small crustaceans are also detritivores, consuming decaying plant and animal matter. Jellyfish: While they might incidentally ingest some detritus while filtering water for food, they are primarily carnivores, feeding on plankton and small fish. Seahorses: These are also not detritivores. They are carnivores, feeding on small shrimp, plankton, and other invertebrates. Therefore, 1,3 and 5 are detritivores.

The Phosphorus Cycle is unique among major biogeochemical cycles because it does not involve a gaseous phase. Instead, phosphorus primarily moves through the lithosphere (rocks), hydrosphere (water), and biosphere (organisms). - Weathering of Rocks: The main source of phosphorus in this cycle comes from the weathering of phosphate-rich rocks. Over time, geological processes break down these rocks, releasing phosphate ions (PO₄³⁻) into the soil and water.
- Absorption by Plants: Plants absorb phosphorus from the soil, and it moves up the food chain as herbivores and carnivores consume plants and other organisms.
- Return to the Soil: When organisms die, decomposition releases phosphorus back into the environment, where it can re-enter the cycle. - Carbon Cycle: The main source of carbon is atmospheric CO₂, released by respiration, combustion, and volcanic activity. - Nitrogen Cycle: Nitrogen is primarily cycled through the atmosphere, with nitrogen fixation (by bacteria) being a key process. - Sulphur Cycle: Sulfur is mainly released from volcanic eruptions, decaying organic matter, and fossil fuel combustion, rather than rock weathering.

* Filter feeders are a subgroup of suspension-feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialised filtering structure. * Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish (including some sharks). Some birds, such as flamingos and certain species of duck, are also filter feeders. Filter feeders can play an important role in clarifying water, and are therefore considered ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms. * Oyster is one of the filter feeders. Pearl Farming - Pearls are the only gemstones in the world that come from a living creature. Mollusks such as oysters and mussels produce these precious jewels.
- Pearl culture practices are present in Gujarat, Maharashtra, Bihar, Odisha, Kerala, Rajasthan, Jharkhand, Goa, and Tripura.

Statement 1 is incorrect: Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Copepods are major secondary producers in the World Ocean. Statement 2 is correct: Diatom refers to any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. They are major primary producers in the food chains of oceans. Statement 3 is correct: Cyanobacteria, also known as Cyanophyta, are a phylum of Gram-negative bacteria that obtain energy via photosynthesis. They are major primary producers in the food chains of oceans. Statement 4 is incorrect: Foraminifera are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell of diverse forms and materials. They are the consumer.

"Blue Carbon" designates carbon that is fixed via coastal ocean ecosystems , rather than traditional land ecosystems, like forests . Although the ocean's vegetated habitats cover less than 0.5% of the seabed, they are responsible for more than 50%, and potentially up to 70%, of all carbon storage in ocean sediments.

Tropical Rainforest: - Hot and moist with year-round rainfall.
- Dense canopy with multiple layers.
- Rapid decomposition due to high temperature and humidity, leaving soil bare.
- Vegetation includes climbers and epiphytes growing on tree branches.
- Different from coniferous, dry deciduous, and mangrove forests. - Species found in these forests include rosewood, mahogony, aini, ebony, etc.
- Distribution in India: mainly found in the Western Ghats, the Northeastern states, the Andaman & Nicobar Islands, and parts of Odisha's Mahanadi Delta. Coniferous Forest: - Found in cold, high-altitude regions.
- Dominated by evergreen trees like pine, fir, spruce, and cedar.
- Needle-like leaves reduce water loss.
- Supports animals like snow leopards, musk deer, and Himalayan black bears.
- Distribution in India: Found in the Himalayan region (Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Arunachal Pradesh, Sikkim). Dry Deciduous Forest: - Trees shed leaves in dry seasons to conserve water.
- Dominated by species like teak, sal, neem, and tendu.
- Soil is fertile, making it good for agriculture.
- Home to tigers, deer, elephants, and langurs.
- Distribution in India: Found in central and western India (Madhya Pradesh, Uttar Pradesh, Rajasthan, Maharashtra, Karnataka, Tamil Nadu, Telangana). Mangrove Forest: - Grow in coastal, saltwater regions.
- Trees have stilt roots to survive in waterlogged conditions.
- Provide breeding grounds for fish and protect coastlines from erosion.
- Home to species like the Royal Bengal Tiger, saltwater crocodiles, and various birds.
- Distribution in India: Found in coastal regions.

The vegetation of savannah consists of grassland with scattered small trees. The forest development in such areas is generally kept in check by one or more or a combination of some conditions. These conditions include fire, grazing herbivores, and seasonal rainfall. 2. Fire is a common occurrence in savannahs and it helps to maintain the grassland by burning out tree saplings. 3. Grazing herbivores also help to maintain the grassland by eating young tree saplings before they can grow into mature trees. 4. Seasonal rainfall also plays a role as it affects the growth of trees and grasses. 1. Burrowing animals and termites, while they do have an impact on the ecosystem, are not the primary factors controlling forest development. 5. Similarly, soil properties can affect the types of vegetation that can grow, but they are not the primary factors controlling forest development in savannahs. Therefore, the correct answer is (c) 2, 3 and 4. Savannah Climate:
- It is a transitional climate between equatorial rainforests and hot deserts. - It has wet and dry seasons like the monsoon climate but with much less rainfall. Unlike the monsoon climate, it lacks a distinct rainy season. - It has only two seasons—winter and summer, with rain occurring in summer. The savanna landscape features tall grasses and scattered short trees. - The savanna is called the ‘big game country’ because thousands of animals are hunted or trapped annually by people worldwide.

Statement 1 is Incorrect: The International Seabed Authority (ISA) regulates seabed mining in international waters. The Global Ocean Commission was a 2013-2016 international initiative of leaders aiming to reverse ocean degradation, focusing on the high seas. Statement 2 is Correct: Like other countries, India can apply for and receive exploration licenses from the ISA for areas beyond national jurisdictions. Since 2014, India has obtained licences from the International Sea Bed Authority for seabed mineral exploration in international waters. Statement 3 is Correct: Rare earth minerals are among the potential resources found on the seabed in international waters, although their commercial viability is still being explored. Therefore, the correct statements are 2 and 3 only.

* Cnidarians: Many cnidarian species, such as corals, develop symbiotic relationships with single-celled algae called zooxanthellae. This symbiosis is crucial for the survival and growth of coral reefs. * Fungi: Fungi are known to form various symbiotic relationships with other organisms, including * Mycorrhizal associations with plant roots, where the fungus helps the plant absorb nutrients in exchange for carbohydrates. * Lichens are a symbiotic relationship between a fungus and an algae or cyanobacteria. * Protozoa: Some protozoa living in the digestive tracts of termites and ruminant animals, helping them break down cellulose. Therefore, all three groups - cnidarians, fungi, and protozoa - have species that can form symbiotic relationships with other organisms.