Biodiversity: Concept | Zoology Optional Notes for UPSC PDF Download

Biodiversity: The Rich Tapestry of Life on Earth

Biodiversity, a term that encapsulates the stunning variety of life on Earth, is defined as "the variability among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems, and the ecological complexes to which they belong; this includes diversity within species, between species, and of ecosystems." It embodies the essence of life's evolution, which has spanned four billion years.

Components of Biodiversity

Biodiversity encompasses a multitude of elements:

1. Species Diversity: This facet accounts for the vast array of distinct biological species on our planet. Today, Earth hosts millions of these unique life forms. Over 70% of known species are animals, while plants and other life forms make up the remaining 22%.

2. Genetic Diversity: Genetic diversity refers to the wide range of unique genetic characteristics within a species. It's the individual traits that give rise to diversity within a particular species.

3. Ecosystem/Community Diversity: Ecosystem diversity is a reflection of the various communities of species that inhabit a given habitat. Different ecosystems are created by combinations of climate, vegetation, and terrain.

Significance of Biodiversity

Biodiversity plays a critical role in nature, ensuring the survival and adaptability of species. Genetic diversity allows populations to thrive in changing environments. Species diversity is vital for understanding the interplay between species and their environments. Ecosystem diversity shapes the variety of species found in different habitats.

Genetic Diversity

• Definition: Genetic diversity pertains to the unique genetic features within a species, which give rise to a wide range of traits among individuals.

• Adaptation: Genetic diversity is essential for a population's ability to adapt to changing conditions. Populations with limited genetic diversity are less capable of coping with environmental changes.

• Alleles: Alleles, variants of specific genes, are crucial components of genetic diversity. Individuals with advantageous alleles tend to survive and pass them on, leading to long-term population continuity.

Species Diversity

• Definition: Species diversity denotes the number of distinct species in a specific region or habitat. In nature, species do not interbreed because they have distinct genetic makeup, though closely related species share many inherited traits.

• Human-Chimp Similarity: For example, humans and chimpanzees share approximately 98.4% of their genes, illustrating the genetic relatedness among species.

Ecosystem/Community Diversity

• Definition: Ecosystem diversity, also known as community diversity, pertains to the communities of interacting species residing in a single habitat. Habitats are defined by their climate, vegetation, and terrain.

• Influence of Ecosystem: The characteristics of an ecosystem significantly affect the diversity of species found within it. Species that are well-suited to a particular environment become more prevalent due to adaptation.

Biodiversity on a Global Scale

• India's Contribution: India is home to about 7% of all known species, highlighting its rich biodiversity.

• Amazon Rainforest: The Amazon rainforest is renowned for hosting the greatest biodiversity in the world.

Measurement of Biodiversity

Biodiversity, which encompasses the variety of life on Earth, is often quantified using several methods to better understand and manage ecosystems. Two key measurements are:

1. Species Richness: Species richness is a fundamental measure of biodiversity, representing the total number of different species within a specific ecological system. The more species in an ecosystem, the higher the species richness. Increased species diversity enhances biodiversity, an essential factor in conservation efforts.

2. Species Evenness: Species evenness complements species richness by measuring the relative abundance of various species in an ecosystem. In areas where all species are present in roughly equal numbers, there is higher species evenness. For example, two areas may have the same species richness, but one may exhibit better evenness, resulting in greater overall species diversity.

These measurements help researchers and conservationists assess the health and stability of ecosystems.

Biodiversity and Food Web

The interconnectedness of life on Earth is evident through the intricate relationships in food webs or chains, which link producers and consumers. These key points illustrate the significance of food webs:

• Producers, primarily green plants, use photosynthesis to convert sunlight and water into energy, while consumers are organisms that rely on others for food.
• Food chains or webs depict the flow of energy and matter from one organism to another. Various food chains, simple or complex, coexist depending on the environment.
• Each species plays a vital role in the overall ecosystem, and altering food chains can have detrimental consequences, including species extinction.
• The extinction of a species disrupts the chain, affecting numerous others, ultimately impacting humans.

Understanding and preserving these food webs are crucial for maintaining ecological balance and biodiversity.

Services Provided by Biodiversity

Biodiversity offers a plethora of essential services at local, regional, and global levels, classified into three categories:

1. Ecosystem Services: These services include maintaining the water cycle, soil formation and protection, nutrient cycling, waste decomposition, climate regulation, and more. Biodiversity helps in pest control and disease prevention.

2. Biological Services: Biodiversity contributes to resources essential for human life, such as food, clothing, housing, energy, and medicine. Many valuable resources are directly or indirectly linked to the diversity of life forms.

   

3. Socio-Cultural Services: Biodiversity plays a significant role in research, education, and tourism. It contributes to human culture, values, and traditions, exemplified by sacred woods preserved by tribal communities in India and similar cultural practices worldwide.

Importance of Biodiversity

Biodiversity, or the variety of life on Earth, holds immense importance in various aspects of our existence:

Ecological Role of Biodiversity:

• Biodiversity contributes significantly to ecosystem health and stability by playing crucial roles in the creation and decomposition of organic matter, removal of atmospheric gases, and regulation of water and nutrient cycles.
• Diverse ecosystems are more productive and resilient, making them better able to withstand environmental stress.
• Biodiversity is fundamental to the provision of essential ecosystem services that humans rely on for their survival.

Economical Role of Biodiversity:

• Biodiversity serves as a resource reservoir for the production of food, cosmetics, and pharmaceuticals.
• It provides raw materials for industrial goods like paper, rubber, wax, oils, lubricants, fragrances, and dyes.
• Crops, livestock, fisheries, and forests are vital sources of food and economic livelihood.
• Many plant species are used for medicinal purposes, contributing to the pharmaceutical industry.
• Plant species offer materials such as wood, fibers, perfumes, lubricants, rubber, resins, poison, and cork.
• Biodiversity generates tourism through national parks and sanctuaries, contributing to local economies.
• Ethnobotanical knowledge of various plant species enriches traditional medicinal practices and holds economic value.

Scientific Role of Biodiversity:

• Each species contributes to our understanding of life's development on Earth and its importance to ecosystem sustainability.
• Biodiversity serves as a valuable resource for scientific research, contributing to our knowledge of various fields, from ecology to genetics.

Ethical Importance:

• Every species has the intrinsic right to exist, and humans should not be the cause of their voluntary extinction.
• Biodiversity plays a role in preserving various cultures, traditions, and spiritual heritage.
• Ethical considerations emphasize the moral obligation to protect and preserve biodiversity.

Causes for Biodiversity Loss:

The loss of biodiversity is primarily driven by human activities. The main factors contributing to biodiversity loss, often referred to as "The Evil Quartet," include:

1. Habitat Loss and Fragmentation: Activities like urbanization, deforestation, and pollution disrupt ecosystems and lead to species loss.
2. Overexploitation: Excessive exploitation of natural resources, such as overfishing, leads to the depletion of species.
3. Alien Species Invasions: Introduction of non-native species can disrupt native ecosystems and lead to extinctions, as seen in the case of invasive species like the Nile perch.
4. Co-extinctions: When a species becomes extinct, it can trigger the extinction of other species that depend on it, creating a chain reaction of extinctions.

Biodiversity Conservation

Preserving biodiversity is of paramount importance as each species plays a significant role in the environment, and once lost, it is irreplaceable. Biodiversity can be conserved through various means:

In-situ Conservation:

• In-situ conservation involves the protection of biodiversity-rich areas, such as biosphere reserves, national parks, and wildlife sanctuaries. For example, the Sunderbans in India, which houses species like the olive ridley sea turtle, mangrove species, and the royal Bengal tiger, is a prime location for in-situ conservation.
• Biodiversity hotspots, regions with high species richness, have been identified globally. India's Western Ghats, Sri Lanka, Indo-Burma, and Himalaya regions are among these hotspots.
• India has a long history of environmental preservation, with sacred groves and traditional practices that protect wildlife and trees.

Ex-situ Conservation:

• Ex-situ conservation occurs when endangered and threatened species are relocated and protected in designated areas, such as botanical gardens and wildlife safaris.
• Cryopreservation techniques are used to preserve the gametes (reproductive cells) of endangered species.
• Seed banks store seeds of economically valuable plants, ensuring their conservation.

Challenges in Biodiversity Conservation:

• Conservation of living natural resources is often given low priority in the face of competing interests and economic gains.
• The exploitation of natural resources for profit can lead to habitat destruction and the decline of biodiversity.
• Inadequate recognition of the value and knowledge associated with species and ecosystems can hinder conservation efforts.
• Uncontrolled industrialization and unplanned urbanization can disrupt ecosystems and lead to habitat loss and fragmentation, posing significant challenges to biodiversity conservation.

Efforts to address these challenges and prioritize biodiversity conservation are essential to safeguard the Earth's rich diversity of life and maintain the balance of ecosystems.