Biogeography & Ecosystems

Statement 1 is correct. The Earth's magnetic field does reverse polarity every few hundred thousand years, on average. Statement 2 is incorrect. The early Earth's atmosphere did not have significant oxygen and likely had a lot of carbon dioxide and other greenhouse gases. Statement 3 is correct. The rise of photosynthetic organisms like cyanobacteria significantly increased the amount of oxygen in the atmosphere over time. Therefore, the correct answer is (c) 1 and 3 only.

Statement 1 is correct: Butterflies are vital pollinators for many flowering plants. A decline in their population can lead to reduced pollination success, affecting fruit and seed production. This, in turn, can disrupt plant communities that rely on butterflies for pollination, potentially impacting entire ecosystems. Statement 2 is incorrect: While some butterfly species may interact with fungi, a decline in butterfly populations is unlikely to cause a drastic increase in fungal infections on cultivated plants. Factors like humidity, temperature, plant health, and fungicide use play a far more significant role in the spread of fungal diseases than butterfly populations. Statement 3 is correct: Butterflies are an essential part of the food web, serving as prey for wasps, spiders, birds, and other insectivorous species. A sharp decline in butterfly populations could negatively impact these predators, disrupting the ecological balance and potentially leading to cascading effects on biodiversity.

Sathyamangalam Wildlife Sanctuary and Tiger Reserve is a protected area and Tiger Reserve along the Western Ghats in the Indian state of Tamil Nadu. Largest among the four tiger reserves (Kalakad-Mundanthurai, Annamalai, Mudumalai and Sathyamangalam) in Tamil Nadu, STR is a significant wildlife corridor in the Nilgiri Biosphere Reserve between the Western Ghats and the rest of the Eastern Ghats, serving as a genetic link to contiguous protected areas including the Biligiriranga Swamy Temple Wildlife Sanctuary, Sigur Plateau, Mudumalai National Park and Bandipur National Park.

Statement 1 is correct: Reduced or zero tillage of the land minimises soil disturbance, promoting better water retention. Less disturbed soil creates a more compact surface that reduces evaporation and allows rainwater to infiltrate deeper into the ground. Statement 2 is incorrect: Applying gypsum before irrigating the field Gypsum (calcium sulfate) is a soil amendment that can improve soil structure and drainage in some situations. However, it doesn't directly conserve water. In some cases, excessive gypsum application might even increase the leaching of nutrients and salts. Statement 3 is correct: Allowing crop residue to remain in the field Leaving crop residue on the soil surface acts like a mulch. This mulch helps suppress weeds, reduces soil erosion, and minimises water evaporation from the soil surface.

Statement 1 is correct: Kharai camels can swim up to three kilometers in seawater. This rare trait allows them to reach offshore mangrove islands, where they forage for food. Statement 2 is correct: Their name "Kharai" comes from the Gujarati word for "salty" because they primarily graze on saline plants and mangroves. This dietary adaptation allows them to thrive in the harsh coastal environment. Statement 3 is incorrect: Kharai camels are herded by local communities (Maldhari) in the Kutch region of Gujarat. Their milk is consumed, and male calves are sometimes sold.
Hence, the correct answer is option A.

The great hornbill, also known as the concave-casqued hornbill, great Indian hornbill or great pied hornbill, is one of the larger members of the hornbill family. It occurs in the Indian subcontinent and Southeast Asia. It is predominantly frugivorous, but also preys on small mammals, reptiles and birds. The great hornbill is native to the forests of India, Bhutan, Nepal, mainland Southeast Asia and Sumatra. Its distribution is fragmented in the Western Ghats and in the foothills of the Himalayas.

Statement 1 is incorrect. While TEEB is a well-respected initiative, it's not directly hosted by UNEP, IMF, and the World Economic Forum. Germany and the European Commission launched it in response to a proposal by G85 Environment Ministers. Statement 2 is correct. TEEB's primary goal is to highlight the economic value of biodiversity and ecosystems. It aims to move beyond traditional economic models that often overlook the significant contributions that nature makes to human well-being. Statement 3 is correct. By providing tools and methodologies, TEEB empowers decision-makers to consider these values when making choices that impact the environment.

Namdapha National Park is located in Arunachal Pradesh, India, in the eastern Himalayas. Due to its significant elevation range, the park experiences a diverse range of climates. The southern regions have a tropical to subtropical climate, while the higher elevations transition to temperate and even Arctic conditions.

Keibul Lamjao National Park is a national park in the Bishnupur district of the state of Manipur in India. It is 40 km² in area, the only floating park in the world, located in North East India, and an integral part of Loktak Lake. The national park is characterized by many floating decomposed plant materials locally called phumdis. To preserve the natural refuge of the endangered Manipur Eld's deer or brow-antlered deer (Cervus eldi eldi), or sangai also called the dancing deer, listed as an endangered species by IUCN. The park, which was initially declared to be a sanctuary in 1966, was subsequently declared to be a national park in 1977 through a gazette notification.

An ecosystem encompasses both living organisms (biotic factors) like plants and animals, and non-living components (abiotic factors) like sunlight, water, and rocks. It highlights the interconnectedness between these elements. Living organisms depend on the environment for survival, while the environment is shaped by the activities of these organisms. Thus ecosystem is a community of organisms together with the environment in which they live.