Write short notes on the following in about 150 words each: (e) Endemism

How to Approach

To address the question on 'Endemism' within a 150-word limit, the approach should be concise yet comprehensive. Start by defining endemism and its ecological significance. Briefly discuss its types (neo- and paleo-endemism) and the key factors contributing to it, such as geographical isolation and unique environmental conditions. Conclude by highlighting its relevance to conservation efforts, particularly in biodiversity hotspots, and mention examples from India.

Model Answer

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Introduction

Endemism refers to the ecological state where a species, genus, or other taxonomic group is unique and restricted to a specific defined geographical area, such as an island, mountain range, or a particular country, and is not found naturally anywhere else in the world. This restricted distribution makes endemic species critical indicators of ecological health and unique evolutionary pathways. The concept, first proposed by A. P. de Candolle in 1813, underscores the irreplaceable nature of certain biological assets within specific locales.

Understanding Endemism

Endemism arises due to various factors, primarily geographical isolation, unique ecological conditions, and evolutionary history. These factors prevent dispersal and gene flow, leading to the development of distinct species adapted to their specific environment.

Types of Endemism

Neoendemism: Refers to relatively young species that have recently evolved and remain confined to their area of origin, often due to rapid speciation.
Paleoendemism: Describes ancient lineages that were once more widespread but are now restricted to relict populations due to extinction elsewhere or competitive exclusion. The Ginkgo tree (Ginkgo biloba) is a classic example of a paleoendemic species.

Factors Contributing to Endemism

Geographical Isolation: Islands, isolated mountain ranges, and large bodies of water act as natural barriers, preventing species movement and promoting independent evolution.
Unique Ecological Conditions: Specific climate patterns, soil compositions, or habitat types create specialized niches, leading to species highly adapted to these precise conditions.
Evolutionary History: Allopatric speciation, where populations are geographically separated and diverge, is a major driver of endemism.

Significance in Conservation

Endemic species are particularly vulnerable to extinction due to their limited ranges and often small population sizes. Habitat loss, climate change, and invasive species pose significant threats. Consequently, areas with high endemism are often designated as 'biodiversity hotspots', demanding focused conservation strategies to protect these irreplaceable biological treasures.

Conclusion

Endemism is a vital concept in biodiversity and conservation biology, highlighting species unique to specific geographical regions. While it signifies rich evolutionary history and adaptation, it also underscores the heightened vulnerability of these species to environmental changes and anthropogenic pressures. Protecting areas with high endemism, such as biodiversity hotspots, is paramount for maintaining global biodiversity and safeguarding the unique evolutionary pathways that contribute to Earth's ecological resilience.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

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Additional Resources

Key Definitions

Endemism

The ecological phenomenon where a species or other taxonomic group is found exclusively in a single defined geographic location and nowhere else in the world.

Biodiversity Hotspots

Biogeographic regions characterized by exceptionally high levels of species richness and endemism (at least 1,500 endemic vascular plant species) that are simultaneously under severe threat from habitat loss (lost at least 70% of original natural vegetation).

Key Statistics

Globally, 36 biodiversity hotspots cover only 2.5% of the Earth's land surface but support more than half of the world's plant species and nearly 43% of bird, mammal, reptile, and amphibian species as endemics.

Source: Conservation International

India is home to 8.58% of mammalian species, 13.66% of avian species, and 11.80% of plant species globally, with a significant proportion being endemic, particularly in regions like the Western Ghats and the Himalayas.

Source: Fifth Report of Convention of Biological Diversity (CBD) 2014, Botanical Survey of India

Examples

Indian Endemic Species

<ul> <li>Asiatic Lion: Endemic to the Gir Forest National Park and its surrounding areas in Gujarat.</li> <li>Nilgiri Tahr: An endangered wild sheep species endemic to the Nilgiri Hills of the Western Ghats.</li> <li>Lion-Tailed Macaque: A rare and endangered primate species found exclusively in the Western Ghats of Southern India.</li> <li>Purple Frog: Also known as the Pignose frog, found only in the rainforests of India's Western Ghats.</li> </ul>

Global Endemic Hotspots

<ul> <li>Madagascar: Over 90% of its native species are endemic due to extreme geographic isolation.</li> <li>Galapagos Islands: Famous for Darwin's finches and giant tortoises, which are all endemic, showcasing unique evolutionary radiation.</li> </ul>

Frequently Asked Questions

▶Why are endemic species more vulnerable to extinction?

Endemic species are highly vulnerable to extinction because their restricted geographical range means they have limited habitats and often smaller populations. Any significant environmental disturbance, such as habitat loss, climate change, pollution, or the introduction of invasive species, can severely impact or wipe out their entire population, as they have no alternative refuge.

Topics Covered

EnvironmentEcologyConservationBiologyEndemismBiodiversityBiogeographyConservation biology

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