APES Review

UNIT 1

Symbiotic Relationships

  • Mutualism: Both species benefit.

  • Commensalism: One species benefits, the other is not affected.

  • Parasitism: One species benefits at the expense of the other.

Trophic Levels

  • Second Law of Thermodynamics: Energy transfer is inefficient.

  • Trophic Levels Energy Transfer:

    • Primary producers: 100%

    • Primary consumers: 10%

    • Secondary consumers: 1%

    • Tertiary consumers: 0.1%

Biotic vs Abiotic

  • Biotic: Living organisms.

  • Abiotic: Non-living elements.

Nitrogen Cycle

  • Nitrogen Fixation: Converts nitrogen gas to ammonia (NH3) or nitrate (NO3).

  • Assimilation: Plants absorb usable nitrogen forms.

  • Denitrification: Conversion of nitrate back to nitrogen gas.

  • Nitrification: Ammonia converted into nitrite (NO2) and nitrate (NO3).

Primary Productivity

  • GPP (Gross Primary Productivity) = NPP (Net Primary Productivity) + R (Respiration)

UNIT 2

Biodiversity

  • Genetic Diversity: Variations within a species.

  • Species Diversity: Number and variety of species in an area.

Measuring Biodiversity

  • Species Richness: Diversity measure (types of species).

  • Species Evenness: Abundance measure (number of individuals).

Ecosystem Services

  • Provisioning: Directly provided products.

  • Regulating: Maintenance of ecosystem processes.

  • Cultural: Non-material benefits and traditions.

  • Supporting: Fundamental processes that allow other services.

Ecological Succession

  • Primary Succession: Occurs in lifeless areas (no soil).

  • Secondary Succession: Soil is present, begins after disturbance.

Island Biogeography

  • Extinction increases, immigration decreases with distance from the mainland; larger land area increases species diversity.

Page 2

Disruptions to Ecosystems

  • Early Succession Species: Thrive with minimal nutrients post-disaster.

  • Late Succession Species: Require more nutrients for survival.

UNIT 3

Survivorship Curves

  • Type 1: High survival until old age (e.g., humans).

  • Type 2: Constant mortality rate (e.g., birds).

  • Type 3: High mortality early (e.g., fish).

K vs. R Selection

  • K-selected species: Low reproductive rates, higher care for offspring.

  • r-selected species: Many offspring, low parental care.

Demographic Transition Model

  1. Stage 1: Pre-industrial; high birth/death, slow growth.

  2. Stage 2: Developing; high birth, lower death, slow growth.

  3. Stage 3: Industrializing; declining birth rate, low death rate.

  4. Stage 4: Developed; low birth/death, stable or declining population.

  5. Stage 5: Post-industrial; too low birth rate, declining population.

Page 3

Population Ecology

  • Intraspecific: Interactions within the same species.

  • Interspecific: Interactions between different species.

Generalists vs. Specialists

  • Generalists: Adapt to a variety of conditions.

  • Specialists: Thrive under specific conditions.

UNIT 4

Earth’s Structure

  • Layers: Crust, mantle, outer core, inner core.

  • Lithosphere: Crust + upper mantle.

  • Asthenosphere: Upper mantle that allows plate movement.

Plate Tectonics

  • Plates move due to mantle convection currents from Earth's heat.

  • Divergent: Plates move apart (e.g., mid-ocean ridges).

  • Convergent: Plates push together (e.g., trenches, mountains).

  • Transform: Plates slide past each other (causes earthquakes).

  • Subduction: Denser plate goes beneath less dense plate.

Geological Processes

  • Weathering: Breakdown of rocks.

  • Erosion: Movement of sediments.

  • Deposition: Formation of rocks from sediments.

Atmosphere

  • Composition: 78% nitrogen, 21% oxygen.

  • Troposphere: Weather occurs here.

  • Stratosphere: Contains the ozone layer (absorbs UV radiation).

Soil Formation

  • O Horizon: Organic matter.

  • A Horizon: Topsoil.

  • B Horizon: Subsoil (minerals accumulate).

  • C Horizon: Weathered rock.

  • R Horizon: Bedrock.

Page 4

Atmospheric Layers

  • Exosphere: No weather.

  • Thermosphere: High UV radiation.

  • Mesosphere: Coldest layer.

  • Stratosphere: Contains ozone.

  • Troposphere: Weather occurs.

Geography

  • Rain Shadows: Dry areas created by elevation blocking precipitation.

El Niño and La Niña

  • El Niño: Warmer tropical Pacific Ocean surface waters, affects the west coast of South America.

  • La Niña: Cooler surface waters; stronger trade winds cause nutrient-rich upwelling.

Soil Properties

  • Porosity: Size of soil pores.

  • Permeability: Water and nutrient flow ability.

  • Higher porosity = higher permeability (order: gravel -> sand -> silt -> clay).

Convection Cells

  • Hadley Cell: 0-30 degrees; hot air rises, cooler air descends.

  • Ferrel Cell: 30-60 degrees; cold air descends, warm air rises.

  • Polar Cell: >60 degrees; warm air rises, cold air descends.

Coriolis Effect

  • Trade winds blow from east to west.

Page 5

Watersheds

  • Canals (streams/rivers) that collect runoff heading to larger water bodies.

FORMULAS

  • Population Density: Population / Area

  • Rule of 70 (Doubling Time): 70 / Percent Growth Rate

  • Population Growth Rate (%): [(Births - Deaths) / Number of People] x 100

  • Gross Primary Productivity: NPP + Respiration