AP Environmental Science | Unit 1

Symbiosis

Close, long term biological interaction between 2 or more different species

Mutualism | Symbiosis

Both organisms benefit from relationship

Commensalism | Symbiosis

One organism benefits while the other is unaffected

Parasitism | Symbiosis

One organism benefits while the other is harmed

Competition for limited resources

Organisms struggle against each other to obtain the same constrained supplies needed for survival

Resource Partitioning

Division of limited resources by competing species to avoid direct conflict and allow coexistence

Spatial | Resource Partitioning

Species use different physical areas of a habitat

Temporal | Resource Partitioning

Species feed or are active at different times

Dietary | Resource Partitioning

Species eat different types/sizes of food

Biome

Large geospatial area on earth defined by its unique climate, soil, plants, and animals

2 Defining Characteristics of a Biome

Temperature & Precipitation

Range of Tropical Locations

Between Tropic of Cancer (23.5*N) and Tropic of Capricorn (23.5*S)

Range of Temperature Biomes

From hot, stable propics near the equator - to freezing, ice-covered polar regions

Range of Boreal Forests & Tundra Biomes

Cast, cold northern rings around earth, transitioning from temperature zones to frozen polar ice caps

Predictable Patterns in Biomes are because…

Of global climate rules

• Sun

• Tilt of Earth

• Movement of air & water

Locations of a biome can shift because…

Long term changes in climate

• Shifts in temperature

• Shifts in rainfall patterns

• Shifts in atmospheric conditions

Lakes, Rivers, Wetlands

Aquatic biomes that can source drinking water for humans

Marine Biome

• Largest aquatic biome

• Saltwater oceans, season, gulfs, estuaries

Estruary Biome

• Brackish water

• Partially enclosed coastal body of water where fresh water rivers & streams meet with salt water from ocean

• EX: Chesapeake Bay

Fresh Water Wetlands

• Land saturated/covered by freshwater for parts of the year

• Has specialized plants and animals

Plants & animals have special adaptations that allow them to survive here

Intertidal Zones

Coastal area where ocean meets land between high & low tides

• Plants & animals have specialized physical features (shells), anchoring methods, & Behavioral traits to adapt/live here

Carbon Source

• Compound releasing carbon dioxide into environment

• Supplies carbon atoms for living organisms to build biomass

Carbon Sink

• Absorbs more carbon from atmosphere than it releases

EX: Oceans, Forests, soil

Long Term Carbon Reservoir

• Sedimentary Rock (limestone)

• Fossil Fuels

Photosynthesis & Cellular Respiration in Carbon Cycle

• Act as perfectly balanced chemical mirror images

• Constantly moves carbon between atmosphere & biosphere efficiently

Combustion of Fossil Fuels

• Increases carbon stored in atmosphere

• Releases ancient carbon into the atmosphere as carbon dioxide

Length of time Nitrogen speeds in reservoirs

Spends little time in reservoir because of its microbial activity & rapid gas exchange - recycling it quickly

Length of time Carbon spends in reservoirs

Spends a long time because it is locked away in long term, geological formations

Nitrogen Fixation

Changes unreactive nitrogen gas from air into usable forms (ammonia)

Nitrogen Assimilation

Process plants & microorganisms use to convert inorganic nitrogen from environment into organic compounds (proteins & amino acids)

The Atmosphere

Largest reservoir in Nitrogen Cycle

How Humans alter Nitrogen Cycle

Use of nitrogen based fertilizers in agriculture

• Introduces more reactive nitrogen into ecosystems - more than the natural process can handle

Phosphorus Sources Examples

• Weathering of rocks

• Runoff

Phosphorous Sink Examples

• Sedimentary rock

• Ocean sediment

Major Phosphorus Reservoir

Sedimentary rock & ocean-bottom sediments

Weathering

Breaks down & dissolves rocks, minerals, and salts right where they sit on Earths surface

Phosphorus cycle moves slowly because…

It lacks a gaseous phase & it relies on weathering of rocks

The Sun | Hydrologic Cycle

Energy source that drives the cycle

Hydraulic Sink Examples

• Oceans

• Ice Caps

• Glaciers

Hydraulic Source Examples

• Groundwater Aquifers

• Atmosphere

Critical Hydraulic Reservoirs for Drinking Water (Humans)

• Ground water

• Surface Water (lakes & rivers)

Infiltration Process

Water on the ground surface enters the soil through

1. Gravity

2. Soil saturation

3. Percolation

4. Runoff Trigger

Primary Productivity

Rate at which producers (plants & algae) convert solar energy into chemical energy/organic biomass though photosynthesis

Mass Based Units of Primary Productivity

• Grams of organic carbon per square meter per year

(gC/m²/yr)

• Grams of dry biomass per square meter per year (g/m²/yr)

Energy Based Units of Primary Productivity

• Kilocalories per square meter per year

(kcal/m²/yr)

• Joules per square meter per year

(J/m²/yr)

Net Primary Productivity (NPP) Equation

GPP-R=NPP

GPP: Gross Primary Productivity

NPP: Net Primary Productivity

R: Respiration

Trophic Level Pyramid Shape

Energy transfer between each level is inefficient (10% energy loss)

The Sun | Tropic Levels

Initial energy source for a trophic pyramid

Producers | Levels of Trophic Pyramid

• Plants, algae, phytoplankton

• Makes their own food through photosynthesis

• Holds most biomass

Primary Consumers | Levels of Trophic Pyramid

• Plant eating animals (rabbits, deer)

• Feeds directly on the producers

• Receives 10% of the energy stored in producer level

Secondary Consumers

• Meat & plant/meat eaters (snakes, spiders)

• Feed on primary Consumers

• Receives 10% of energy from 2nd level

Tertiary Consumers

• Top meat eaters (hawks, wolves, orcas)

• Feed on secondary Consumers

• Sits near top of food chain with lowest biomass

10% Rule

Energy is raised from one trophic level to the next and only 10% of that energy is passed

10% Rule with 2nd Law of Thermodynamics

The other 90% of the energy lost is lost to heat

Food Web

• Complex, web-like network with multiple paths

• Stronger stability: if one food source dies, the animal can switch to another options

• More accurate

Food Chain

• Follows one, direct & linear path of energy

• Too simple

• Fragile: if one plant or animal dies, the rest of the chain collapses