MP

APES Unit 1 Study Guide Notes

Ecosystems

  • Ecosystems: Interaction of living (biotic) & nonliving (abiotic) things in a specific area.
  • Habitat: Specific environmental conditions that a given species needs to survive.
  • Environment: The broader natural world, including ecosystems.

Symbiosis

  • Symbiosis: General term for close interactions between different species, which can be beneficial or harmful.
  • Mutualism: A specific type of symbiosis that benefits both species involved (e.g., bees and flowering plants).

Terrestrial Biomes

  • Biome: An area sharing average yearly temperature and precipitation patterns.
  • Examples of biomes with lower temperature and precipitation compared to tropical rainforests:
    • Temperate forest
    • Boreal forest
    • Woodland/shrubland
    • Temperate grassland
  • Desert Species: Cacti are adapted to their environment with thick, waxy cuticles to conserve water and prevent loss from heat.
  • Impact of Global Climate Change: Warming may expand tropical rainforests' range to subtropical regions.

Aquatic Biomes

  • Mangrove Tree Adaptations:
    • Thicker membranes/leaf pores that prevent salt from entering, or pump salt out.
    • Stilt-like roots that provide stability and support against water.
  • Characteristics of Estuaries:
    • Locations where rivers meet oceans, resulting in mixing of fresh and saltwater.
    • High productivity due to sediment deposition from rivers.
  • Biodiversity in Estuaries: Nutrient-rich sediments support diverse animal species.

Carbon Cycle

  • Atmosphere as a Carbon Reservoir: Plays a critical role in regulating Earth’s temperature; increased carbon leads to increased temperatures.
  • Carbon Sources vs. Sinks:
    • Sources: Fossil fuel combustion, decomposition, respiration, volcanic activity, forest fires.
    • Sinks: Sedimentary rocks, old-growth forests (e.g., redwoods/sequoias), soil.
  • Differential Effects of Carbon Release:
    • Carbon from fossil fuels has been out of circulation for millions of years, while cellular respiration carbon is part of a current cycle.

Biogeochemical Cycle Terminology

  • Reservoir: Temporary storage areas for matter.
  • Source: Processes that move matter between reservoirs.
  • Sink: Reservoirs that store more matter than they release.

Nitrogen Cycle

  • Differences between Nitrogen and Carbon Cycles:
    • Nitrogen cycles faster and is biologically unavailable in its atmospheric form (N₂).
  • Nitrogen Fixation: Conversion of atmospheric N₂ into biologically available forms like ammonia (NH₃) or nitrate (NO₃).
  • Forms of Nitrogen Fixation:
    • Biotic: Soil bacteria (e.g., Rhizobacteria).
    • Abiotic: Lightning strikes, fossil fuel combustion.
  • Process Descriptions:
    • Assimilation: Uptake of nitrogen by plants and animals.
    • Ammonification: Conversion of organic nitrogen into ammonium (NH₄) by microbes.
    • Nitrification: Conversion of ammonium (NH₄) into nitrate (NO₃) by bacteria.
    • Denitrification: Conversion of nitrates (NO₃/NO₂) back into N₂ gas by denitrifying bacteria.

Phosphorus Cycle

  • Differences in Phosphorus Cycle:
    • Phosphorus has no gaseous phase; it does not enter the atmosphere.
    • Major reservoir is in rocks and sediments, leading to slower cycling.
  • Weathering vs. Erosion:
    • Weathering: Breakdown of rocks into smaller sediment pieces containing phosphates.
    • Erosion: Movement of these sediments into ecosystems via water or wind.
  • Limiting Nutrient: Phosphorus is limited due to its slow cycling from rocks and sediments.

Trophic Levels & 10% Rule

  • Energy Transfer: In a trophic pyramid, only 10% of energy is transferred to the next trophic level (90% lost as heat).
  • Trophic Pyramid Example (starting with 10,000 kcal):
    • Producers: 10,000 kcal
    • Primary Consumers: 1,000 kcal
    • Secondary Consumers: 100 kcal
    • Tertiary Consumers: 10 kcal
  • Large Land Requirement for Tertiary Consumers: Due to the 10% rule, much more biomass of lower levels is needed to support them.

Hydrologic Cycle

  • Driving Energy Source: Sunlight heats water allowing evaporation to occur.
  • Steps:
    • Evaporation: Sunlight converts water from liquid to vapor.
    • Precipitation: Condensed vapor returns as rain or snow.
  • Vegetative Influence: Dense vegetation increases water infiltration and transpiration rates.
  • Largest Freshwater Reservoir: Ice caps and glaciers.

Primary Productivity

  • Definition: Rate at which plants convert sunlight into organic matter (glucose).
  • Units: Kilocalories/m²/year.
  • Respiration Loss: Energy used by plants during their own cellular respiration.
  • NPP Calculation Formula: NPP = GPP - RL
    where GPP is Gross Primary Productivity and RL is Respiration Loss.
  • NPP Examples:
    1. Fremont High School:
    • GPP: 1221 g C/m²/yr, RL: 450 g C/m²/yr → NPP = 771 g C/m²/yr.
    1. Golf Course:
    • NPP: 1,100 g C/m²/yr, RL: 350 g C/m²/yr → GPP = 1450 g C/m²/yr.
    1. Alfalfa Patch:
    • NPP: 304 kcal/m²/yr, GPP: 421 kcal/m²/yr → RL = 117 kcal/m²/yr.

Food Webs

  • Arrows in Food Webs: Indicate the direction of energy and matter transfer.
  • Population Dynamics: Decreasing secondary consumer populations can lead to increased primary consumer populations, impacting primary producers negatively.
  • Organisms in Food Web: Tertiary & quaternary consumer example: Leopard seal; only secondary consumer example: Squid, Blue whale, Fish.