Unit 1 APES Final

1.1 Ecosystems

Ecosystem Basics

• Ecosystem Components: Components include individual (a single organism), population (group of same species), community (all living organisms), ecosystem (all living and nonliving things), and biome (large area with similar climate conditions).

• Organism Interactions: Types include competition (organisms fighting over resources), predation (one organism using another for energy), mutualism (relationship benefits both organisms), commensalism (relationship benefits one, doesn't impact the other), and symbiosis (close, long-term interaction between two different species).

• Competition Reduction: Resource partitioning through temporal (using resources at different times), spatial (using different areas), and morphological (using different body features) differences.

1.2 Terrestrial Biomes

Definition

• Terrestrial Biomes Defined: Defined by temperature and precipitation, determining unique adaptations for organisms in that biome.

• Latitude: Influences climate and biome distribution, as biomes are patterned predictably depending on their distance from the equator.

• Nutrient Availability: Impacts plant survival, especially regarding soil nutrients and water availability.

• Climate Change: Causes biomes to shift in location as climate conditions change over time.

1.3 Aquatic Biomes

Characteristics

• Characteristics Defined: Defined by salinity (salt content), depth (sunlight penetration), flow (determines plant & animal survival), and temperature (O2 levels).

• Freshwater Biomes: Types include rivers (high O2, nutrient-rich sediments), lakes (standing bodies of fresh water), and wetlands (soil submerged/saturated, shallow enough for emergent plants), which provide flood control and pollutant filtering.

• Estuaries: Areas where fresh and salt water mix, supporting mangroves and salt marshes; high productivity from nutrients in sediments.

• Coral Reefs: Diverse marine biomes with mutualistic relationships between coral and algae.

• Intertidal Zones: Require adaptations to crashing waves and desiccation, as they are narrow bands of coastline between low and high tide.

• Open Oceans: Characterized by low productivity but high overall O2 production due to their large scale.

1.4 Carbon Cycle

Overview

• Carbon Cycle Overview: Carbon moves between sources (add C to atmosphere) and sinks (store more C than release).

• Processes: Photosynthesis (removes CO2 from atmosphere) and respiration (adds CO2 to atmosphere) cycle carbon.

• Ocean Exchange: Direct CO2 exchange leads to ocean acidification due to increasing atm. CO2.

• Long-Term Storage: Sedimentation and burial store carbon long-term in sedimentary rock or fossil fuels.

• Human Impact: Extraction and combustion increase concentration of atmospheric CO2.

• 1.5 Nitrogen Cycle

Overview

• Nitrogen Cycle Overview: Nitrogen cycles between reservoirs (plants, soil, atmosphere), mainly the atmosphere.

• Nitrogen Fixation: Converts N2 into usable forms like ammonia (NH3) or nitrate (NO3-).

• Transformations: Assimilation (plants & animals take in N), ammonification (waste & dead biomass convert to NH3), nitrification (NH4 into nitrite then nitrate), and denitrification (soil N converts into nitrous oxide).

• Human Impacts: Climate change from N2O, ammonia volatilization (excess fertilizer leads to NH3 gas), and eutrophication from fertilizer runoff (nitrates leach into waters).

1.6 Phosphorus Cycle

Overview

• Phosphorus Cycle Overview: Phosphorus cycles slowly with weathering as a primary source; rocks and sediments are major reservoirs.

• Processes: Assimilation (P absorbed by plant roots) and decomposition cycle phosphorus.

• Storage: Sedimentation (forms sediments) and geological uplift (tectonic plate collision forcing up rock layers) affect long-term storage.

• Eutrophication: Results from excess N & P, causing algae blooms, blocking sunlight and hypoxia (lower O2 levels).

1.7 Hydrologic Cycle

Overview

• Hydrologic Cycle Overview: Water moves between reservoirs, driven by solar energy. State of matter and location are key;

• Processes: Evaporation (liquid to gas), transpiration (plants draw groundwater from roots up to leaves), runoff (flows over earth's surface) and infiltration (trickles through soil into groundwater).

• Reservoirs: Oceans are the largest; ice caps and groundwater are important freshwater sources.

1.8 Primary Productivity

Overview

• Primary Productivity Overview: Measures solar energy conversion to organic compounds (rate of photosynthesis).

• Calculations: Net Primary Productivity (NPP) = Gross Primary Productivity (GPP) minus Respiration Loss (RL).

• Factors: Water availability, temperature, and nutrients affect NPP; high NPP supports biodiversity.

1.9 & 1.10 Trophic Levels & The 10% Rule

Definitions

• Energy Laws: Energy is conserved but lost as heat during transfers (1st & 2nd laws of thermodynamics).

• 10% Rule: Only about 10% of energy from one trophic level makes it to the next level; dictates energy transfer between trophic levels.

• Trophic Pyramids: Model energy flow through an ecosystem; available energy decreases with each step up the food chain.

1.11 Food Chains & Food Webs

Definitions

• Food Webs: Shows how matter and energy flow through ecosystems, displaying interconnected food chains.

• Trophic Cascades: Occur with the removal or addition of top predators, affecting lower trophic levels; causes ripple effect down trophic levels.