Ecosystem Dynamics: Cycling and Energy Flow

Element Cycling

• Element cycling moves and transforms abiotic and biotic elements
• Includes inputs, outputs, and internal cycling in an ecosystem
• Obeys the first law of thermodynamics: matter cannot be created or destroyed

Carbon Cycle

• Interconnected network of biological and physical processes
• Organisms move carbon between themselves and their surroundings
• Demonstrates functioning and persistence of ecosystems over time

Primary Producers

• Base of the food web
• Provide organic carbon to other organisms
• Examples: Cyanobacteria, eukaryotic algae, plants

Primary Consumers

• Consume primary producers
• Examples: Herbivores, grazers
• Consumed by secondary consumers or carnivores/scavengers

Decomposers/Detritivores

• Break down remains of other organisms into basic compounds
• Examples: Fungi, earthworms

Energy Flow

• Energy does not cycle through an ecosystem
• New energy must be continuously harvested
• A trophic pyramid (energy pyramid) forms because energy transfer is not 100% efficient
• Energy is lost through heat and work
• Biomass decreases from one trophic level to the next

Plants and Adaptations

• Plants have independently evolved adaptations (e.g., leaf shape, color changes) to adapt to climates
• Plants provide physical structure to each terrestrial biome

Aquatic Biomes

• Tropical Reefs:
  • Reflect climate, nutrient and oxygen availability, and sunlight penetration depth
  • Depth often exposes benthos
  • Marine biome
• Freshwater Streams:
  • Water chemistries vary with terrain and nutrient levels
  • Moving water, often well-oxygenated
  • River/stream ecosystems overlap with terrestrial environments
• Both aquatic biomes have various producers and consumers
• Nutrient levels in reefs can be low, but primary production is high and tied to producers

Terrestrial Biomes

• Temperate Deciduous Forests:
  • Moderate climate, hardwood deciduous trees, four distinct seasons
  • Nutrient-rich soils from annual leaf fall
  • High biodiversity (birds, small mammals)

Urban Landscapes

• Full of life despite human impact
• Major primary producers: vascular plants
• Major primary consumers: mammals, birds, and insects

Biogeochemical Cycles

• Coral reefs receive nutrients from freshwater, rain runoff, and open ocean
• Coral reefs are a hotspot of life (high diversity and density)

Trophic Levels/Food Chains/Consumer Groups

• Consumers include corals, anemones, fish, crustaceans, bivalves, gastropods, worms, echinoderms, and various visiting vertebrates.
• Animals (terrestrial and aquatic) eat each other, take prey from streams, and animals' waste and remains can enter water.