IB DP Biology Conservation of biodiversity Study Notes

IB DP Biology Conservation of biodiversity Study Notes at IITian Academy focus on specific topic and type of questions asked in actual exam. Study Notes focus on IB Biology syllabus with guiding questions of

What factors are causing the sixth mass extinction of species?
How can conservationists minimize the loss of biodiversity?

Standard level and higher level: 3 hours

IBDP Biology 2025 -Study Notes -All Topics

A4.2.1—Biodiversity as the variety of life in all its forms, levels and combinations

Biodiversity: The Tapestry of Life

Biodiversity, the variety of life on Earth, is a marvel of nature. It exists at multiple levels, from the genetic diversity within species to the rich tapestry of ecosystems. Ecosystem diversity encompasses the varied combinations of species living together in communities, shaped by diverse environments and geographical ranges. Species diversity reflects the evolutionary tree of life, with countless species exhibiting unique body plans, internal structures, life cycles, and nutritional modes. Genetic diversity within species, both between populations and within populations, is essential for adaptation and survival. Species with limited genetic diversity face increased vulnerability to threats like inbreeding and environmental change.

The preservation of biodiversity is crucial for our planet’s health and well-being. It provides us with essential ecosystem services, such as clean air and water, fertile soil, and climate regulation. Protecting biodiversity means safeguarding the intricate web of life that supports all living things, including ourselves.

Additional Interesting Facts:

Over 8 million species may exist on Earth, although only about 2 million have been identified.
Tropical rainforests are biodiversity hotspots, home to a significant portion of the world’s species.
Human activities, such as habitat destruction and climate change, are major threats to biodiversity.

A4.2.2—Comparisons between current number of species on Earth and past levels of biodiversity

Earth’s history is marked by periods of flourishing biodiversity interspersed with mass extinctions. While millions of species exist today, many remain undiscovered. Fossil records reveal five major extinction events, with the most recent one wiping out the non-avian dinosaurs 66 million years ago. Between these catastrophic events, biodiversity generally increases gradually. Currently, we’re experiencing a period of high biodiversity, but human activities threaten to trigger a sixth mass extinction.

A4.2.3—Causes of anthropogenic species extinction

Human activities have significantly accelerated the rate of species extinction. Primary causes contribute to this alarming trend:

1. Overexploitation:

Excessive harvesting of plants and animals for food, medicine, or other resources.
Overfishing, particularly of large predatory fish, has depleted marine ecosystems.
Illegal hunting and poaching threaten numerous species, including elephants, rhinos, and tigers.

2. Habitat Destruction:

Deforestation, agriculture, and urbanization destroy natural habitats, fragmenting populations and reducing biodiversity.
Conversion of forests and grasslands into agricultural land leads to habitat loss and fragmentation.
Pollution and climate change further degrade habitats, making them unsuitable for many species.

3. Invasive Species:

Non-native species introduced to new environments can outcompete native species, prey on them, or spread diseases.
Invasive species often lack natural predators or competitors in their new habitats, allowing them to proliferate rapidly.
Examples include the introduction of rats and cats to islands, which has led to the extinction of many bird species.

4. Pollution:

Pollution from industrial activities, agriculture, and transportation contaminates air, water, and soil.
Chemical pollutants can poison organisms and disrupt ecosystems.
Climate change, driven by greenhouse gas emissions, is altering habitats and causing species extinction.

Visual Representation:

Mitigating the Crisis

To address the issue of human-driven extinction, it is crucial to implement conservation strategies that protect habitats, reduce pollution, and control invasive species. International cooperation and sustainable practices are essential to safeguard biodiversity and ensure a healthy planet for future generations.

A4.2.4—Causes of ecosystem loss

Human activities are the primary cause of ecosystem loss. These activities can be direct, such as clearing land for agriculture or urban development, or indirect, such as pollution and climate change. Some specific causes include:

Land-use change: Conversion of natural habitats into agricultural land and urban areas.
Urbanization: Expansion of cities and infrastructure, leading to habitat loss and fragmentation.
Overexploitation: Excessive harvesting of resources like fish, timber, and wildlife.
Pollution: Contamination of air, water, and soil, harming ecosystems and species.
Climate change: Alteration of climate patterns, leading to habitat loss and species extinction.
Dam construction: Disruption of river ecosystems and water flow.
Mining and smelting: Destruction of habitats and pollution of water and soil.

These factors collectively threaten biodiversity and ecosystem services, impacting both human well-being and the planet’s overall health.

A4.2.5—Evidence for a biodiversity crisis

The term “biodiversity crisis” refers to the unprecedented loss of ecosystems and species occurring today. To scientifically validate this claim, evidence of these losses is crucial.

The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is a key source of information on biodiversity trends. They periodically assess the state of biodiversity and produce reports.

Direct monitoring of various biodiversity indicators also provides valuable evidence. These indicators include:

Population size: Tracking the number of individuals within a species.
Range: Monitoring the geographic area occupied by a species.
Species diversity: Assessing the number of species in an ecosystem.
Ecosystem health: Evaluating the overall condition of an ecosystem, including factors like richness, evenness, and area.
Genetic diversity: Measuring the genetic variation within a species.

Citizen science initiatives, where individuals contribute to data collection, are vital in monitoring biodiversity and detecting early signs of decline. By tracking changes over time, we can identify and address threats to biodiversity before it’s too late.

A4.2.6—Causes of the current biodiversity crisis

The Earth has experienced several mass extinctions throughout its history, but the current biodiversity crisis is unique in its rapid pace and human causation. Since the 1970s, human activities have significantly accelerated the rate of species extinction and ecosystem degradation.

Key Causes of the Biodiversity Crisis:

Overexploitation:
- Overfishing, overhunting, and overharvesting of resources have depleted populations and disrupted ecosystems.
Habitat Loss and Degradation:
- Deforestation, urbanization, and agriculture have destroyed and fragmented natural habitats.
Pollution:
- Pollution from industrial activities, agriculture, and transportation pollutes air, water, and soil, harming ecosystems and species.
Climate Change:
- Rising temperatures and changing climate patterns are altering ecosystems and causing species extinction.
Invasive Species:
- The introduction of non-native species can outcompete native species, disrupt ecosystems, and cause extinctions.

To address this crisis, it is crucial to implement conservation strategies, reduce human impact on ecosystems, and promote sustainable practices. By understanding the causes and consequences of biodiversity loss, we can work towards a more sustainable future for both humans and the planet.

A4.2.7—Need for several approaches to conservation of biodiversity

The biodiversity crisis is a complex issue that requires a multifaceted approach. No single strategy can effectively address the challenges facing biodiversity. A combination of in-situ and ex-situ conservation methods is necessary to protect species and ecosystems.

In-situ Conservation

In-situ conservation involves protecting species in their natural habitats. This approach is considered ideal, as it allows species to adapt to environmental changes and interact with other species in a natural setting. Strategies for in-situ conservation include:

Establishing protected areas: Creating national parks, wildlife sanctuaries, and marine reserves.
Habitat restoration: Restoring degraded habitats to their natural state.
Species reintroduction: Reintroducing species that have been extirpated from an area.
Habitat management: Managing habitats to ensure the survival of target species.
Community-based conservation: Engaging local communities in conservation efforts.

Ex-situ Conservation

Ex-situ conservation involves protecting species outside their natural habitats. This approach is often used for endangered species or those that cannot be adequately protected in their natural habitats. Strategies for ex-situ conservation include:

Zoos and aquariums: Keeping animals in captivity for breeding and research.
Botanical gardens: Cultivating plants in controlled environments.
Seed banks: Storing seeds for future conservation and restoration efforts.
Cryopreservation: Preserving genetic material at extremely low temperatures.

By combining in-situ and ex-situ conservation efforts, we can increase the chances of preserving biodiversity and ensuring the survival of species for future generations.

A4.2.8—Selection of evolutionarily distinct and globally endangered species for conservation prioritization in the EDGE of Existence programme

The EDGE of Existence program prioritizes conservation efforts for species that are both Evolutionarily Distinct and Globally Endangered. This approach aims to maximize the conservation impact by focusing on species with unique evolutionary histories and those facing imminent extinction threats.

Key criteria for EDGE species:

Evolutionary distinctiveness: Species with few close relatives are considered more valuable from an evolutionary perspective.
Global endangerment: Species facing a high risk of extinction due to threats like habitat loss, poaching, or climate change.

By prioritizing these EDGE species, conservation efforts can help preserve unique genetic diversity and prevent the loss of entire evolutionary lineages. This targeted approach ensures that limited conservation resources are allocated effectively to protect the most vulnerable species.

IB DP Biology Conservation of biodiversity Study Notes