Ecology Chapter 2.5-2.6 Flashcards

Gross and Net Primary Productivity

• Gross Primary Productivity (GPP): Total energy or biomass produced by photosynthesis in plants per unit area per unit time.
• Net Primary Productivity (NPP): Energy or biomass remaining after deducting respiratory losses from GPP, calculated using NPP = GPP - R.

Gross and Net Secondary Productivity

• Gross Secondary Productivity (GSP): Total energy gained by consumers through absorption per unit area per unit time, calculated as GSP = food eaten - fecal loss.
• Net Secondary Productivity (NSP): Energy or biomass remaining for growth and reproduction after respiratory losses, calculated using NSP = GSP - R.

Organism Roles in Ecosystems

• Producers: Organisms, specifically photoautotrophs, that convert sunlight into food through photosynthesis.
• Consumers: Organisms that obtain energy by consuming other organisms; includes herbivores, carnivores, and omnivores.
• Decomposers: Organisms that break down dead organic matter, essential for recycling nutrients like nitrogen through processes involving ammonia and nitrates.

Photosynthesis and Respiration

• Photosynthesis Reaction: 6CO2 + 6H2O + light → C6H12O6 + 6O2; transforms light energy into chemical energy.
• Process of Photosynthesis: Involves chlorophyll absorbing sunlight, splitting water molecules, combining hydrogen with CO2, and producing glucose.
• Respiration Reaction: C6H12O6 + 6O2 → 6CO2 + 6H2O + energy; transforms chemical energy into heat during cellular processes.

Water, Carbon, Nitrogen, and Phosphorus Cycles

• Water Cycle: Involves absorption by plant roots, transpiration, condensation into clouds, precipitation, and eventual return to oceans.
• Carbon Cycle: Carbon fixation by autotrophs and its return to the atmosphere through respiration and decomposition; fossil fuel formation from organic matter.
• Nitrogen Cycle: Key processes include nitrogen fixation by bacteria, nitrification, and denitrification, facilitating nitrogen uptake by plants.
• Phosphorus Cycle: Minerals released from rocks, uptake by plants, cycling through organisms, and return to soil after decay.

Productivity Concepts

• Gross Productivity: Total energy or biomass gain per unit area per unit time.
• Net Productivity: Energy or biomass left post-respiratory losses.

Population Dynamics

• Limiting Factors: Environmental elements that restrict population growth; include temperature, water, nutrient availability, and carrying capacity.
• Carrying Capacity: Sustainable population size an ecosystem can support over time.
• S-Population Curve: Characterized by exponential growth, slowing transition, and stabilization at carrying capacity.
• J-Population Curve: Exhibits continual exponential growth without stabilization.

Density-Dependent and Density-Independent Factors

• Density-Dependent Factors: Affect birth/death rates based on population size; include resources and disease.
• Density-Independent Factors: Impact populations regardless of density; include natural disasters and climate change.

Strategies and Survivorship Curves

• K-strategists: Species that mature slowly, produce few large offspring, and invest heavily in parental care, often found in stable environments (Type I survivorship curve).
• R-strategists: Species that mature quickly, produce many small offspring with low parental investment, typically found in unstable environments (Type III survivorship curve).

Succession in Ecosystems

• Succession: Progressive change in community structures over time, classified into primary and secondary succession.
• Primary Succession: Occurs on uncolonized substrates, like bare rock.
• Secondary Succession: Follows the removal of a previous community, such as after fire or agriculture.

Community Dynamics

• Pioneer Community: Early seral stage with low productivity and accumulating biomass.
• Climax Community: Final stage with high productivity yet low net productivity, typically reaching a balance between production and respiration.

Ecological Energetics

• Study of Energy Flow: Focuses on how solar energy drives ecosystems; involves energy transfer, storage, and nutrient recycling.

Test your knowledge on gross primary productivity (GPP) and net primary productivity (NPP) with these flashcards. Define the terms and calculate their values based on given data. Perfect for anyone studying ecology or environmental science.