Ecosystem Dynamics: Energy Flow and Adaptation
Ecosystems: Energy and Matter
Ecosystems function as factories requiring energy and matter. Matter exists as abiotic (inert) and biotic (organic) components. Energy, primarily from the sun, is captured by autotrophs (producers) through photosynthesis. Energy is lost as heat or waste. Heterotrophs (consumers) obtain energy by consuming organic matter. Consumers include herbivores (primary), carnivores (secondary and tertiary), and decomposers (fungi and bacteria).
Trophic Relationships:
- Food chains illustrate the transfer of matter and energy.
- Food webs depict all trophic connections.
- The 10% rule states that only 10% of energy transfers to the next level.
- Energy pyramids show energy at each level.
- Numerical pyramids represent the number of individuals.
- Biomass pyramids show the amount of organic matter.
Ecosystem Regulation and Change
Self-Regulation: Abiotic and biotic factors limit population growth, maintaining equilibrium. Factors include soil, light, temperature, and water.
Human Impact: Activities alter ecosystems. Pests are organisms causing harm. Biological control uses natural methods to manage pests.
Population Dynamics: A population is all individuals of a species in an ecosystem. Carrying capacity is the maximum population size an environment can support. Limiting factors include density-dependent (disease) and density-independent (temperature) factors.
Ecological Succession:
- Primary succession occurs in areas without previous vegetation.
- Pioneer species are the first to colonize.
- Climax community is the stable, mature stage.
- Secondary succession occurs in previously inhabited areas.
Soil and Environmental Factors
Soil formation is influenced by bedrock, climate, topography, and organisms. Soil components include biotic (living) and abiotic (mineral particles, humus). Soil horizons include A (surface), B (accumulation), and C (bedrock contact).
Human-Induced Environmental Changes:
- Climate change
- Population growth
- Resource depletion
- Biodiversity loss
Sustainable development aims for responsible resource use. Biodiversity encompasses all species and genetic variations.
Adaptation and Survival
Adaptations are traits enabling survival in specific environments. They can be morphological (e.g., bird wings), behavioral (e.g., migration), or physiological (e.g., temperature regulation).
Aquatic Adaptations:
Salinity affects aquatic organisms. Euryhaline organisms tolerate salinity changes, while stenohaline organisms do not. Fish have fins, gills, and swim bladders. Aquatic plants have adaptations for buoyancy and gas exchange.
Terrestrial Adaptations:
Homeothermic organisms maintain constant body temperature. Poikilothermic organisms’ temperature varies. Eurythermic organisms tolerate temperature changes, while stenothermic organisms do not. Terrestrial organisms have protective coverings, respiratory systems, and skeletal structures for support.