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Honors Biology
Table of Contents
Unit 20 Overview: Conservation Biology & Environment
20.1 Biodiversity and Conservation Strategies
20.2 Climate Change and Global Environmental Issues
20.3 Sustainable Resource Management

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20.1 Biodiversity and Conservation Strategies

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Biodiversity, the variety of life on Earth, is under threat from human activities. Habitat loss, overexploitation, and invasive species are driving extinction rates to alarming levels, endangering countless species and ecosystems.

Conservation strategies aim to protect and restore biodiversity. These include creating protected areas, implementing captive breeding programs, and restoring degraded habitats. International efforts focus on biodiversity hotspots and sustainable development to preserve Earth's rich biological heritage.

Types of Biodiversity

Levels of Biodiversity

  • Biodiversity encompasses the variety of life at all levels of biological organization
    • Includes diversity within species, between species, and among ecosystems
  • Ecosystem diversity consists of the variety of habitats, communities, and ecological processes in the living world
    • Examples include forests, grasslands, deserts, and coral reefs
  • Species diversity refers to the variety of different species in an ecosystem or on Earth
    • Estimated 10-100 million species exist globally (insects, plants)
  • Genetic diversity is the variety of genes within a species
    • Leads to variation in traits such as disease resistance, coloration, and behavior
    • Provides raw material for adaptation and evolution (antibiotic resistance in bacteria)

Threats to Biodiversity

Habitat Loss and Fragmentation

  • Habitat fragmentation occurs when large, continuous habitats are divided into smaller, isolated patches
    • Caused by human activities like deforestation, urbanization, and agriculture
    • Reduces biodiversity by limiting species' ability to disperse and find mates or resources
  • Endangered species are at risk of extinction due to factors such as habitat loss, overexploitation, or disease
    • Examples include tigers, giant pandas, and many amphibian species
  • Extinction is the disappearance of a species from Earth
    • Can be local (extirpation) or global
    • Current extinction rates are 100-1000 times higher than background rates due to human activities

Overexploitation and Invasive Species

  • Overexploitation involves unsustainably harvesting resources faster than they can be replenished
    • Includes overfishing, poaching, and illegal wildlife trade (shark finning, elephant ivory)
  • Invasive species are non-native organisms that cause ecological or economic harm in a new environment
    • Often lack natural predators and outcompete native species for resources
    • Examples include kudzu in the southeastern US and zebra mussels in the Great Lakes

Conservation Strategies

Protected Areas and Habitat Restoration

  • Conservation biology is the scientific study of Earth's biodiversity with the aim of protecting species, habitats, and ecosystems
  • In-situ conservation protects species in their natural habitats
    • Involves creating protected areas like national parks, wildlife refuges, and marine reserves (Yellowstone, Great Barrier Reef)
  • Ex-situ conservation protects species outside their natural habitats
    • Includes captive breeding programs in zoos and seed banks (California condor, Svalbard Global Seed Vault)
  • Habitat restoration involves restoring degraded ecosystems to their natural state
    • May involve removing invasive species, planting native vegetation, or creating wildlife corridors
  • Biosphere reserves are protected areas that promote biodiversity conservation and sustainable development
    • Consist of core protected areas surrounded by buffer zones allowing some human activity

Biodiversity Hotspots and International Efforts

  • Hotspots are regions with high levels of endemic species that are under threat from habitat loss
    • Contain at least 1,500 endemic plant species and have lost at least 70% of original habitat
    • Examples include Madagascar, the Caribbean, and the California Floristic Province
  • International treaties and organizations work to protect biodiversity globally
    • Convention on Biological Diversity (CBD) aims to conserve biodiversity and ensure sustainable use of resources
    • International Union for Conservation of Nature (IUCN) assesses species' conservation status and guides conservation efforts
  • Reducing deforestation, promoting sustainable agriculture, and mitigating climate change are critical for preserving Earth's biodiversity

Key Terms to Review (24)

National Park Service: The National Park Service (NPS) is a U.S. federal agency established to manage and protect the country's national parks, monuments, and historical sites. It plays a crucial role in conserving biodiversity and promoting conservation strategies through the preservation of ecosystems, habitats, and cultural resources within these protected areas.
California Condor Recovery: California Condor Recovery refers to the concerted efforts to restore the population of the California condor, a critically endangered bird species, through conservation and breeding programs. This initiative highlights the importance of preserving biodiversity and employing targeted conservation strategies to save species on the brink of extinction, ultimately benefiting entire ecosystems.
Great Green Wall: The Great Green Wall is an ambitious African-led initiative aimed at combating desertification, land degradation, and climate change by creating a mosaic of green and productive landscapes across the Sahel region. This initiative focuses on planting trees, restoring degraded lands, and improving food security while also fostering biodiversity and climate resilience in a region heavily affected by environmental challenges.
Water purification: Water purification is the process of removing contaminants from water to make it safe for consumption and other uses. This vital process helps ensure access to clean drinking water, which is essential for human health and environmental sustainability. Effective water purification methods contribute to the conservation of biodiversity by protecting ecosystems from pollutants that can harm aquatic life and disrupt natural habitats.
Evenness: Evenness refers to the relative abundance of different species within a particular ecological community. It measures how equally individuals are distributed among the various species present, contributing to the overall diversity of an ecosystem. High evenness means that species are represented by similar numbers of individuals, while low evenness indicates that a few species dominate, potentially leading to ecological imbalances and affecting conservation efforts.
Biodiversity indices: Biodiversity indices are quantitative measures that provide insights into the variety and variability of life in a given ecosystem. These indices help ecologists and conservationists assess the health and stability of ecosystems, guiding conservation strategies and management decisions. By evaluating species richness, evenness, and overall diversity, these indices can highlight areas in need of protection and help track changes over time due to environmental pressures or conservation efforts.
Convention on Biological Diversity: The Convention on Biological Diversity (CBD) is an international treaty aimed at conserving biodiversity, promoting sustainable use of its components, and ensuring fair and equitable sharing of benefits arising from genetic resources. Established in 1992 at the Earth Summit in Rio de Janeiro, it connects environmental conservation with sustainable development, highlighting the importance of biodiversity for human well-being and ecosystem health.
Invasive Species: Invasive species are non-native organisms that, when introduced to a new environment, can cause significant harm to the ecosystem, economy, or human health. These species often outcompete native species for resources, disrupt local habitats, and alter ecosystem functions, making their management a crucial aspect of biodiversity conservation efforts.
Endangered Species Act: The Endangered Species Act (ESA) is a significant piece of legislation enacted in 1973 aimed at protecting and recovering imperiled species and their habitats. The act establishes legal protections for species classified as endangered or threatened, creating a framework for conservation efforts and promoting biodiversity. By prioritizing the preservation of ecosystems, the ESA helps maintain the balance of natural systems and addresses threats such as habitat destruction, pollution, and over-exploitation.
Ecological Niche: An ecological niche refers to the role and position a species has in its environment, encompassing all its interactions with biotic and abiotic factors. This includes how it obtains resources, how it interacts with other organisms, and how it contributes to the ecosystem's structure and function. Understanding ecological niches is essential for recognizing how biodiversity is maintained and how ecosystems can be conserved.
Habitat destruction: Habitat destruction refers to the process by which natural habitats are altered or destroyed, leading to a significant decline in biodiversity and ecosystem health. This phenomenon is often driven by human activities such as urbanization, deforestation, agriculture, and industrial development, which not only displace species but also disrupt the ecological balance necessary for their survival. The impact of habitat destruction extends beyond the immediate loss of species, as it also influences ecosystem services that are vital for human well-being and environmental sustainability.
World Wildlife Fund: The World Wildlife Fund (WWF) is a global conservation organization that focuses on wildlife preservation and environmental sustainability. It aims to protect the world's most vulnerable species and their habitats through various initiatives, advocacy, and partnerships with local communities, governments, and businesses. The WWF plays a vital role in promoting biodiversity conservation strategies that address the challenges of habitat loss, climate change, and overexploitation of natural resources.
Protected Areas: Protected areas are regions designated for the conservation of nature, biodiversity, and cultural resources, with restrictions on human activities to maintain their ecological integrity. These areas serve as crucial habitats for wildlife, preserve ecosystems, and provide spaces for research and recreation. By safeguarding these regions, protected areas play a vital role in conservation strategies aimed at preventing biodiversity loss and promoting sustainable use of natural resources.
Habitat restoration: Habitat restoration is the process of returning a degraded or destroyed ecosystem to its original condition or to a state that is as close as possible to its natural, pre-disturbance state. This practice is crucial for conserving biodiversity, as it helps revive the populations of various species and supports ecological functions that may have been lost due to human activities or natural disasters.
Climate change: Climate change refers to significant and lasting alterations in temperature, precipitation, wind patterns, and other elements of the Earth's climate system, largely driven by human activities such as burning fossil fuels, deforestation, and industrial processes. These changes impact natural ecosystems and biogeochemical cycles, influencing everything from nutrient cycling to water availability. Furthermore, climate change poses significant risks to biodiversity, leading to habitat loss and extinction threats for many species.
Sustainable Development: Sustainable development is a guiding principle aimed at meeting the needs of the present without compromising the ability of future generations to meet their own needs. It balances economic growth, environmental stewardship, and social inclusion to create a more equitable and environmentally friendly world. This concept is crucial in addressing pressing issues such as climate change and biodiversity loss by promoting practices that support ecological integrity while also fostering economic and social well-being.
Carbon sequestration: Carbon sequestration is the process of capturing and storing atmospheric carbon dioxide (CO2) to mitigate climate change and reduce global warming. This natural or artificial process helps in reducing the concentration of CO2 in the atmosphere, thus playing a vital role in climate regulation, biodiversity preservation, and conservation strategies. By sequestering carbon, ecosystems such as forests, wetlands, and oceans can act as carbon sinks, helping to balance carbon levels and support a healthier environment.
Ecosystem diversity: Ecosystem diversity refers to the variety of ecosystems within a certain area, encompassing the different biological communities and their interactions with the physical environment. This concept is important because it highlights how various ecosystems contribute to overall biodiversity and ecological balance. A rich diversity of ecosystems can enhance resilience to environmental changes, provide a range of habitats for species, and support numerous ecological processes essential for life.
Pollination: Pollination is the process by which pollen is transferred from the male anthers of a flower to the female stigma, leading to fertilization and the production of seeds. This critical mechanism not only facilitates reproduction in flowering plants but also plays a significant role in maintaining biodiversity and supporting ecosystems through interactions with various species.
Genetic diversity: Genetic diversity refers to the total number of genetic characteristics in the genetic makeup of a species. It is crucial for the adaptability and resilience of populations, allowing species to survive in changing environments and resist diseases. High genetic diversity within a population can enhance survival rates and reproduction, which plays an essential role in maintaining ecosystem health and functionality.
Species diversity: Species diversity refers to the variety of different species within a specific ecosystem or on the entire planet, encompassing both the number of species and their relative abundance. This concept is crucial for understanding ecological balance and interactions, as it influences ecosystem resilience, productivity, and stability. A higher species diversity often leads to healthier ecosystems, which can adapt more easily to changes and disturbances.
Species richness: Species richness refers to the number of different species present in a specific area or ecosystem. It is a crucial component of biodiversity, reflecting the variety of life forms that contribute to the overall health and resilience of ecosystems. Higher species richness often indicates a more stable ecosystem, as diverse species can fulfill various ecological roles, leading to increased productivity and better resistance to environmental changes.
Biome: A biome is a large ecological area characterized by distinct plant and animal groups, which are adapted to the environment and climate of that region. Biomes are defined by factors such as temperature, precipitation, and soil type, leading to the formation of various ecosystems within each biome. These vast regions play a significant role in the Earth's biodiversity and ecological interactions.
Trophic levels: Trophic levels refer to the hierarchical positions in an ecosystem that categorize organisms based on their primary source of energy. Each level represents a different stage in the flow of energy and nutrients, starting from producers at the base, followed by various levels of consumers. Understanding these levels helps clarify the roles of different organisms in food webs and their impact on biodiversity and ecological balance.