6.1 Understanding ecological systems and processes

Ecosystems are complex networks of living and non-living components that interact in intricate ways. From producers to consumers and decomposers, each plays a vital role in the flow of energy and matter through the system.

Biodiversity is crucial for ecosystem stability, providing resilience against disturbances. Natural processes like succession and adaptation shape environments over time, while climate influences species distribution and ecosystem structure. Understanding these dynamics is key to environmental conservation.

Ecosystem Components and Interactions

Components of ecosystems

Top images from around the web for Components of ecosystems

• 

  File:Trophic levels.jpg - Wikimedia Commons View original

  Is this image relevant?

• 

  Ecosystem and Eutrophication Lab | Biology II Laboratory Manual View original

  Is this image relevant?

• 

  Energy Flow through Ecosystems · Concepts of Biology View original

  Is this image relevant?

• 

  File:Trophic levels.jpg - Wikimedia Commons View original

  Is this image relevant?

• 

  Ecosystem and Eutrophication Lab | Biology II Laboratory Manual View original

  Is this image relevant?

1 of 3

Top images from around the web for Components of ecosystems

• 

  File:Trophic levels.jpg - Wikimedia Commons View original

  Is this image relevant?

• 

  Ecosystem and Eutrophication Lab | Biology II Laboratory Manual View original

  Is this image relevant?

• 

  Energy Flow through Ecosystems · Concepts of Biology View original

  Is this image relevant?

• 

  File:Trophic levels.jpg - Wikimedia Commons View original

  Is this image relevant?

• 

  Ecosystem and Eutrophication Lab | Biology II Laboratory Manual View original

  Is this image relevant?

1 of 3

• Biotic components
  • Producers: Autotrophs convert solar energy into chemical energy through photosynthesis (plants, algae, cyanobacteria)
  • Consumers: Heterotrophs obtain energy by consuming other organisms
    • Primary consumers (herbivores): Feed on producers (rabbits, insects, zooplankton)
    • Secondary consumers (carnivores): Feed on primary consumers (hawks, snakes, fish)
    • Tertiary consumers: Feed on secondary consumers (lions, killer whales, humans)
    • Omnivores: Consume both plants and animals (bears, pigs, many bird species)
  • Decomposers: Break down dead organic matter, releasing nutrients back into the ecosystem (bacteria, fungi, earthworms)
• Abiotic components
  • Non-living factors influence ecosystem function
    • Climate: Temperature, precipitation, sunlight affect species distribution and productivity
    • Topography: Elevation, slope, aspect influence microclimates and habitat diversity
    • Soil: Texture, nutrients, moisture content affect plant growth and nutrient cycling
    • Water: Availability and quality impact aquatic and terrestrial ecosystems
• Interactions within ecosystems
  • Predation: Consumers feed on other organisms, transferring energy and regulating populations (wolves hunting elk)
  • Competition: Organisms vie for limited resources, shaping community structure (trees competing for light)
  • Symbiosis: Close relationships between different species
    • Mutualism: Both species benefit (pollination by bees and flowers)
    • Commensalism: One species benefits while the other is unaffected (barnacles on whales)
    • Parasitism: One species (parasite) benefits at the expense of the other (host) (tapeworms in mammals)

Energy flow in ecological systems

• Energy flow
  • Unidirectional: Energy enters ecosystems through producers and moves through trophic levels
  • Trophic levels: Positions in a food chain or food web
    1. Primary producers: Convert solar energy into chemical energy (plants, algae)
    2. Primary consumers: Herbivores feed on primary producers (grasshoppers, deer)
    3. Higher-level consumers: Carnivores and omnivores feed on lower trophic levels (birds, wolves)
  • Energy loss: Only 10% of energy is transferred between trophic levels due to heat loss and inefficiencies
• Biogeochemical cycles: Cycling of matter within ecosystems
  • Carbon cycle: Exchange of carbon between the atmosphere, biosphere, hydrosphere, and lithosphere (photosynthesis, respiration, fossil fuel combustion)
  • Nitrogen cycle: Conversion of nitrogen between various forms (nitrogen fixation by bacteria, nitrification, denitrification)
  • Phosphorus cycle: Movement of phosphorus through the environment (weathering of rocks, uptake by organisms, decomposition)
  • Water cycle: Continuous movement of water through evaporation, transpiration, precipitation, and infiltration

Biodiversity and Ecological Processes

Biodiversity for ecosystem stability

• Biodiversity: Variety of life at all levels (genetic, species, ecosystem)
• Ecosystem stability
  • Resistance: Ability to withstand disturbances without significant changes in structure or function
  • Resilience: Capacity to recover from disturbances and return to a stable state
• Importance of biodiversity
  • Functional redundancy: Multiple species perform similar roles, providing a buffer against disturbances (diverse grasslands withstand drought better)
  • Niche partitioning: Species occupy different ecological niches, reducing competition and increasing resource use efficiency (diverse bird communities in forests)
  • Ecosystem services: Benefits provided by ecosystems (pollination by diverse insect communities, nutrient cycling by soil microbes)
  • Increased resistance to invasive species and disease outbreaks (diverse plant communities resist invasive plants)

Processes shaping natural environments

• Succession: Gradual change in species composition over time
  • Primary succession: Colonization of newly exposed or formed substrates (lava flows, glacial retreat)
  • Secondary succession: Recovery of an ecosystem after a disturbance (fire, logging)
• Disturbance: Events disrupt ecosystem structure and function
  • Natural disturbances: Wildfires, hurricanes, floods, droughts shape ecosystem dynamics
  • Anthropogenic disturbances: Deforestation, urbanization, pollution alter ecosystems
• Adaptation: Evolutionary process by which organisms become better suited to their environment over generations
  • Natural selection: Differential survival and reproduction of individuals with favorable traits (beak shapes in Darwin's finches)
  • Coevolution: Reciprocal evolutionary changes in interacting species (long nectar tubes in flowers and long tongues in pollinators)
• Climate: Long-term patterns in temperature, precipitation, and other atmospheric conditions
  • Influences species distribution, ecosystem structure, and ecological processes (biomes, plant growth forms)
  • Climate change: Shifts in climate patterns due to natural and anthropogenic factors, affecting ecosystem composition and function (rising temperatures, altered precipitation patterns)