Earth's biosphere teems with life, from microscopic organisms to towering trees. Ecosystems, the building blocks of this living world, are intricate networks where living things interact with their environment. They're diverse, ranging from tiny tide pools to vast rainforests.

Biodiversity, the variety of life on Earth, is crucial for healthy ecosystems. It includes genetic diversity within species, the range of species in an area, and the diversity of ecosystems themselves. Biodiversity supports essential services like food production, climate regulation, and water purification.

Ecosystems and their components

Components of an ecosystem

• An ecosystem is a community of living organisms interacting with each other and their non-living environment
  • Ecosystems can vary in size, from small microhabitats (tide pools, rotting logs) to large biomes (tropical rainforests, tundra)
  • Ecosystems are interconnected through the movement of energy and matter (nutrient cycling, migration of species)
• Biotic factors are the living components of an ecosystem
  • Examples include plants (producers), animals (consumers), and microorganisms (decomposers)
  • Biotic factors interact with each other through various relationships (predation, competition, symbiosis)
• Abiotic factors are the non-living components of an ecosystem
  • Examples include temperature, light, water, soil, and nutrients
  • Abiotic factors influence the distribution, abundance, and adaptations of living organisms

Processes in ecosystems

• Energy flow is the transfer of energy from one trophic level to another
  • Energy enters ecosystems through primary producers (photosynthesis) and moves up the food chain
  • Energy is lost at each trophic level due to heat, respiration, and incomplete consumption
• Nutrient cycling is the continuous movement of essential elements through an ecosystem
  • Major nutrient cycles include the carbon, nitrogen, and phosphorus cycles
  • Nutrients are recycled through the actions of decomposers, which break down dead organic matter
  • Nutrient availability influences the productivity and structure of ecosystems

Biodiversity and ecosystem function

Levels of biodiversity

• Genetic diversity is the variation in genes within a species
  • Allows for adaptation to changing environments and resilience to diseases
  • Maintains the evolutionary potential of species
• Species diversity is the number and relative abundance of different species within an ecosystem
  • Contributes to the stability and productivity of ecosystems
  • Provides a variety of ecological roles and functions
• Ecosystem diversity encompasses the variety of habitats, communities, and ecological processes within a given area
  • Includes the interactions between biotic and abiotic components
  • Provides a range of ecosystem services (carbon sequestration, water purification, climate regulation)

Importance of biodiversity

• Biodiversity enhances ecosystem functioning
  • Increases productivity through niche complementarity and resource partitioning
  • Improves resource use efficiency and nutrient cycling
  • Enhances resilience to disturbances and environmental changes (climate change, invasive species)
• Biodiversity contributes to the provision of essential ecosystem services
  • Supports food production through pollination, pest control, and soil fertility
  • Regulates climate through carbon sequestration and evapotranspiration
  • Purifies water and air through filtration and detoxification processes
  • Provides recreational, cultural, and aesthetic values for human well-being

Terrestrial and aquatic biomes

Terrestrial biomes

• Tundra: cold, dry, and treeless biome with low-growing vegetation (mosses, lichens, sedges)
• Taiga (boreal forest): subarctic biome dominated by coniferous trees (spruce, fir, pine)
• Temperate forests: mild climate with distinct seasons, dominated by deciduous trees (oak, maple, beech)
• Grasslands: characterized by grasses and herbaceous plants, with few trees (prairies, steppes, savannas)
• Deserts: dry biome with scarce vegetation adapted to water scarcity (cacti, succulent plants)
• Tropical rainforests: warm, humid, and species-rich biome with tall, broadleaf evergreen trees

Aquatic biomes

• Freshwater biomes
  • Lentic ecosystems (still water): lakes, ponds, and wetlands
  • Lotic ecosystems (flowing water): rivers, streams, and springs
• Marine biomes
  • Coastal ecosystems: estuaries, coral reefs, and kelp forests
  • Open ocean ecosystems: pelagic (water column) and benthic (seafloor) zones
• Abiotic factors (temperature, salinity, light penetration) influence the distribution and adaptations of aquatic organisms
  • Aquatic organisms exhibit adaptations for locomotion, buoyancy, and gas exchange in water
  • Marine organisms are adapted to varying salinity levels (osmoregulation)

Threats to biodiversity vs conservation strategies

Threats to biodiversity

• Habitat loss and fragmentation
  • Land-use change, deforestation, and urbanization reduce available space and resources for species
  • Fragmentation isolates populations and disrupts dispersal and gene flow
• Overexploitation of natural resources
  • Overfishing, poaching, and unsustainable harvesting lead to population declines and extinctions
  • Examples include the ivory trade, shark finning, and illegal logging
• Invasive species
  • Non-native species introduced to new ecosystems can outcompete native species and alter ecosystem functioning
  • Examples include the brown tree snake in Guam and the zebra mussel in North American lakes
• Climate change
  • Anthropogenic greenhouse gas emissions cause shifts in species distributions, phenology, and biotic interactions
  • Climate change can lead to habitat loss, species range shifts, and increased risk of extinctions
• Pollution
  • Air, water, and soil contamination have detrimental effects on the health and survival of organisms
  • Examples include oil spills, plastic pollution in oceans, and pesticide runoff

Conservation strategies

• Protected areas
  • Establishing national parks, wildlife reserves, and marine protected areas to safeguard critical habitats and species
  • Examples include the Yellowstone National Park and the Great Barrier Reef Marine Park
• Ecosystem-based management
  • Balancing human activities with the maintenance of biodiversity and ecosystem services
  • Incorporating ecological principles into land-use planning, fisheries management, and forestry practices
• Sustainable resource management
  • Implementing practices that minimize the impact of human activities on biodiversity
  • Examples include sustainable forestry (selective logging), fisheries (catch limits), and agriculture (crop rotation, integrated pest management)
• Restoration ecology
  • Rehabilitating degraded ecosystems and reintroducing native species to promote biodiversity recovery
  • Examples include wetland restoration, reforestation, and coral reef restoration projects
• Environmental education and public awareness
  • Fostering a sense of stewardship and encouraging environmentally responsible behaviors
  • Raising awareness about the importance of biodiversity and the impacts of human activities
  • Engaging communities in conservation efforts and decision-making processes