AP Environmental Science - The Whole Shabang

Unit 1 - The Living World - Ecosystems (6-8%): Levels of Ecology, from Simple to Complex

• Individual

• Population

• Community

• Ecosystem

• Biome

Unit 1 - The Living World - Ecosystems (6-8%): Individual

one organism (elk)

Unit 1 - The Living World - Ecosystems (6-8%): Population

group of individuals of same species (elk herd)

Unit 1 - The Living World - Ecosystems (6-8%): Community

all living organisms in an area

Unit 1 - The Living World - Ecosystems (6-8%): Ecosystem

all living and nonliving things in an area (plants, animals, rocks, soil, water, air)

Unit 1 - The Living World - Ecosystems (6-8%): Biome

the plants and animals found in a given region (determined by climate) Ex: tropical rainforest

Unit 1 - The Living World - Ecosystems (6-8%): Organism Interactions

• Competition

• Predation

• Mutualism

• Commensalism

Unit 1 - The Living World - Ecosystems (6-8%): Competition

organisms fighting over a resource like food or shelter; limits population size

Unit 1 - The Living World - Ecosystems (6-8%): Predation

one organism using another for energy source (hunters, parasites)

Unit 1 - The Living World - Ecosystems (6-8%): Mutualism

relationship that benefits both organisms (coral reef)

Unit 1 - The Living World - Ecosystems (6-8%): Commensalism

relationship that benefits one organism and doesn’t impact the other (birds nest in trees)

Unit 1 - The Living World - Ecosystems (6-8%): Predation (+/-)

• Herbivores

• True Predators

• Parasites

• Parasitoids

Unit 1 - The Living World - Ecosystems (6-8%): Herbivores

(plant eaters) eat plants for energy (giraffe & tree)

Unit 1 - The Living World - Ecosystems (6-8%): True Predators

(carnivores) kill and eat prey for energy (leopard & giraffe)

Unit 1 - The Living World - Ecosystems (6-8%): Parasites

uses a host organism for energy, often without killing the host & often living inside host

• Ex: mosquitoes, tapeworms, sea lamprey

Unit 1 - The Living World - Ecosystems (6-8%): Parasitoids

lays eggs inside a host organism; eggs hatch & larvae eat host for energy

• Ex: parasitic wasps, bot fly

Unit 1 - The Living World - Ecosystems (6-8%): Symbiosis

• sym = together | bio = living | osis = condition

• Any close and long-term interaction between two organisms of different species

• Mutualism (+/+) commensalism (+/0), and parasitism (+/-) are all symbiotic relationships

Unit 1 - The Living World - Ecosystems (6-8%): Mutualism

Organisms of different species living close together in a way that benefits both

• Ex: (animals) Coral provides reef structure & CO2 for algae; algae provide sugars for coral to use as energy

• Lichen = composite organism of fungi living with algae; algae provide sugars (energy) & fungi provides nutrients

Unit 1 - The Living World - Ecosystems (6-8%): Competition

Reduces population size since there are fewer resources available & fewer organisms can survive

• Resource partitioning

• Temporal partitioning

• Spatial partitioning

• Morphological partitioning

Unit 1 - The Living World - Ecosystems (6-8%): Resource Partitioning

different species using the same resource in different ways to reduce competition

Unit 1 - The Living World - Ecosystems (6-8%): Temporal Partitioning

Using resource at different times, such as wolves & coyotes hunting at different times (night vs. day)

Unit 1 - The Living World - Ecosystems (6-8%): Spatial Partitioning

using different areas of a shared habitat (different length roots)

Unit 1 - The Living World - Ecosystems (6-8%): Morphological Partitioning

using different resources based on different evolved body features

Unit 1 - The Living World - Ecosystems (6-8%): Biome

the plants & animals found in a region; based on yearly temperature + precipitation (climate)

• Rain forest

• Tiaga

• Temperature Deciduous Forest

• Grasslands

• Desert

• Tundra

The community of organisms (plants & animals) in a biome are uniquely adapted to live in that biome

• Camels and cacti

• Shrubs and wildflowers

Unit 1 - The Living World - Ecosystems (6-8%): Biome Characteristics

• Latitude (distance from equator) determines temperature & precipitation which is why biomes exist in predictable pattern on earth

• Biome chart can also predict where on earth biomes are found

  • Tundra & Boreal = higher latitude (60°C +)

  • Temperate = mid latitude (30° - 60°C)

  • Tropical closer to equator

• Biomes are defined by average annual temperature & precipitation

Unit 1 - The Living World - Ecosystems (6-8%): Nutrient Availability

Plants need soil nutrients to grow, so availability determines which plants can survive in a biome

Ex: frozen soils of tundra don’t allow nutrients in dead organic matter to be broken down by decomposers, causing:

• Low soil nutrients

• Low water availability

• Few plants survive here

Unit 1 - The Living World - Ecosystems (6-8%): Tropical Rainforest

nutrient-poor soil

(high temperature & rainfall —> rapid decomposition of organic matter

acidic soil + high rainfall —> nutrient leaching)

Unit 1 - The Living World - Ecosystems (6-8%): Boreal Forest

nutrient-poor soil

(low temperature & low decomposition rate of organic matter)

Unit 1 - The Living World - Ecosystems (6-8%): Temperate Forest

nutrient-rich soil

(lots of dead organic matter - leaves & warm temperature/moisture for decomposition)

Unit 1 - The Living World - Ecosystems (6-8%): Shifting Biomes

Biomes shift in location on earth as climate changes

• Ex: warming climate will shift boreal forests further north as tundra permafrost soil melts & lower latitudes become too warm for aspen & spruce

Unit 1 - The Living World - Ecosystems (6-8%): Characteristics of Aquatic Biomes

• Salinity

• Flow

• Depth

• Temperature

Unit 1 - The Living World - Ecosystems (6-8%): Salinity

How much salt there is in a body of water, determines which species can survive & usability for drinking (Fresh water vs. estuary (a partially enclosed coastal body of water where fresh water from rivers and streams mixes with saltwater from the ocean) vs. ocean)

Unit 1 - The Living World - Ecosystems (6-8%): Flow

Determines which plants & organisms can survive, how much O₂ can dissolve into water

Unit 1 - The Living World - Ecosystems (6-8%): Depth

Influences how much sunlight can penetrate and reach plants below the surface for photosynthesis

Unit 1 - The Living World - Ecosystems (6-8%): Temperature

Warmer water holds less dissolved O₂ so it can support fewer aquatic organisms

Unit 1 - The Living World - Ecosystems (6-8%): Freshwater: Rivers & Lakes

• Rivers have high O₂ due to flow mixing water & air, also carry nutrient-rich sediments (deltas & flood plains = fertile soil)

• Lakes = standing bodies of fresh H₂O (key drinking water source

  • Littoral

  • Limnetic

  • Profundal

  • Benthic

Unit 1 - The Living World - Ecosystems (6-8%): Littoral

shallow water w/emergent plants

Unit 1 - The Living World - Ecosystems (6-8%): Limnetic

where light can reach (photosynthesis)

• No rooted plants, only phytoplankton

Unit 1 - The Living World - Ecosystems (6-8%): Profundal

too deep for sunlight (no photosynthesis)

Unit 1 - The Living World - Ecosystems (6-8%): Benthic

murky bottom where inverts (bugs) live, nutrient-rich sediments

Unit 1 - The Living World - Ecosystems (6-8%): Freshwater: Wetlands

area with soil submerged/saturated in water for at least part of the year, but shallow enough for emergent plants

• Plants living here have to be adapted to living with roots submerged in standing water (cattails, lily pads, reeds)

Unit 1 - The Living World - Ecosystems (6-8%): Benefits of Wetlands

• Stores excess water during storms, lessening flood damage to property

• Recharges groundwater by absorbing rainfall into soil

• Roots of wetland plants filter pollutants from water draining through

• High plant growth rates growth rates due to lots of water & nutrients (dead organic matter) in sediments

Unit 1 - The Living World - Ecosystems (6-8%): Estuaries

areas where rivers empty into the ocean

• Mix of fresh & salt water (species adapt to this ex: mangrove trees)

• High productivity (plant growth) due to nutrients in sediments deposited in estuaries by river

• Salt Marsh

• Mangrove Swamps

Unit 1 - The Living World - Ecosystems (6-8%): Salt Marsh

• Estuary hab. along coast in temperate climates

• Breeding ground for many fish & shellfish species

Unit 1 - The Living World - Ecosystems (6-8%): Mangrove Swamps

• Estuary hab. along coast of tropical climates

• Mangrove trees with long, stilt roots stabilize shoreline & provide habitat for many species of fish & shellfish

Unit 1 - The Living World - Ecosystems (6-8%): Coral Reef

• Warm shallow waters beyond the shoreline; most diverse marine (ocean) biome on earth

• Mutualistic relationship between coral (animals) & algae (plants)

  • Coral take CO₂ out of ocean to create calcium carbonate exoskeleton (the reef) & also provide CO₂ to the algae

  • Algae live in the reef and provide sugar (energy) to the coral through photosynthesis

  • Both species rely on the other:

    • Coral couldn’t survive without energy from algae

    • Algae need the home of the reef & CO₂ from the coral

Unit 1 - The Living World - Ecosystems (6-8%): Intertidal Zones

• Narrow band of coastline between high & low tide

• Organisms must be adapted to survive crashing waves & direct sunlight/heat during low tide

  • Ex: Barnacles, sea stars, crabs that can attach themselves to rocks

• Shells & tough outer skin can prevent drying out (desiccation) during low tides

  • Different organisms are adapted to live in different zones

    • Ex: Spiral wrack (type of seaweed) curls up & secretes mucus to retain water during low tide

Unit 1 - The Living World - Ecosystems (6-8%): Open Ocean

So large that algae & phytoplankton of ocean produce a lot of earth’s O₂ & absorb a lot of atmospheric CO₂

• Low productivity per m² as algae & phytoplankton can only survive in photic zone

Unit 1 - The Living World - Ecosystems (6-8%): Photic Zone

area where sunlight can reach (photosynthesis)

Unit 1 - The Living World - Ecosystems (6-8%): Aphotic Zone (abyssal)

area too deep for sunlight

• Species rely on detritus from photic zone or chemosynthetic microbes at hydrothermal vents for energy

Unit 1 - The Living World - Ecosystems (6-8%): Productivity

the rate of formation of biomass in the ecosystem. It can also be referred to as the energy accumulated in the plants by photosynthesis.

Unit 1 - The Living World - Ecosystems (6-8%): Carbon Cycle Overview

• Movement of molecules that contain Carbon (CO₂, glucose, CH₄) between sources and sinks

• Some steps are very quick (fossil fuel combustion); some are very slow (sedimentation & burial)

• Leads to imbalance in which reservoirs or sinks are storing carbon

• Atmosphere is key C reservoir: increasing levels of C in atm. Leads to global warming

• Carbon sink

  • Ocean (algae & sediments), plants, soil

• Carbon source:

  • Fossil fuel (oil, coal, nat gas) combustion

  • Animal aq. (cow burps & farts = CH₄)

  • Deforestation, releases CO₂ from trees

Unit 1 - The Living World - Ecosystems (6-8%): Key Carbon Reservoir

Atmosphere; Leads To Global Warming

Unit 1 - The Living World - Ecosystems (6-8%): Carbon Sink

reservoir that take in more carbon than it releases

Unit 1 - The Living World - Ecosystems (6-8%): Carbon Source

reservoir that releases more carbon than it takes in

Unit 1 - The Living World - Ecosystems (6-8%): Photosynthesis

• Plants, algae, phytoplankton

• Removes CO₂ from the atmosphere & converts it to glucose

• Glucose = biological form of C & stored (chemical) energy in form of sugar

• CO₂ sink

Unit 1 - The Living World - Ecosystems (6-8%): Cellular Respiration

• Done by plants & animals to release stored energy

• Use O₂ to break glucose down & release energy

• Releases CO₂ into atmosphere

• CO₂ source (adds CO₂ to atmosphere)

Unit 1 - The Living World - Ecosystems (6-8%): Photosynthesis and Cellular Respiration

• Both processes are very quick

• Cycle C between biosphere & atmosphere in balanced amount (no net C increase in atmosphere)

Unit 1 - The Living World - Ecosystems (6-8%): Ocean & Atmosphere

• Direct Exchange

  • Happens very quickly & in equal directions, balancing levels of CO₂ between atmosphere & ocean

• Because of direct exchange, increasing atmospheric CO₂ also increases ocean CO₂ leading to ocean acidification

• Algae & phytoplankton

  • Coral, mollusks, and some zooplankton

• Sedimentation

• Burial

Unit 1 - The Living World - Ecosystems (6-8%): Direct Exchange

CO₂ moves directly between atmosphere & the ocean by dissolving into & out of ocean water at the surface

Unit 1 - The Living World - Ecosystems (6-8%): Ocean Acidification

the decreasing pH of the ocean, primarily due to the absorption of excess carbon dioxide (CO2) from the atmosphere. This process is a major concern because it negatively impacts marine ecosystems and the organisms that live there. 

Unit 1 - The Living World - Ecosystems (6-8%): Algae & phytoplankton

take CO₂ out of the ocean & atmosphere through photosynthesis

Unit 1 - The Living World - Ecosystems (6-8%): Coral, mollusks, and some zooplankton

Also take CO₂ out of the ocean to make calcium carbonate exoskeletons

Unit 1 - The Living World - Ecosystems (6-8%): Sedimentation

Calcium carbonate precipitates out as sediment & settles on ocean floor

Unit 1 - The Living World - Ecosystems (6-8%): Burial

Over long periods of time, pressure of water compresses C-containing sediments on ocean floor into sedimentary rock (limestone, sandstone) - long-term C reservoir

Unit 1 - The Living World - Ecosystems (6-8%): Burial, Extraction, & Combustion

• Burial

  • Sediments (bits of rock, soil, organic matter) compacted into sedimentary rock by weight of overlying rock layers or water

• Fossil Fuels (FF)

• Extraction & Combustion

• Burial (formation of FFs) takes far longer than extraction & combustion, which means they increase concentration of CO₂ in atmosphere

Unit 1 - The Living World - Ecosystems (6-8%): Burial

slow, geological process that stores C in underground sinks like sedimentary rock or fossil fuels

• Sediments (bits of rock, soil, organic matter) compacted into sedimentary rock by weight of overlying rock layers or water

Unit 1 - The Living World - Ecosystems (6-8%): Fossil Fuels (FF)

formed from fossilized remains of organic matter into coal (ex. plants) or oil (ex. plankton). Their decomposition produces natural gas (CH₄)

Unit 1 - The Living World - Ecosystems (6-8%): Extraction & Combustion

Digging up or mining FFs & burning them as energy source: releases CO₂ into atmosphere

Unit 1 - The Living World - Ecosystems (6-8%): Nitrogen Cycle Overview

• Movement of N-containing molecules between source & sinks/reservoirs

  • Source release N into atmosphere; sinks take N out of the atmosphere in increasing amounts

• N reservoirs hold Nh for relatively short periods of time compared to C cycle

  • Ex: plants, soil, atmosphere

• Atmosphere = main N reservoir

  • N in atmosphere exists mostly as N₂ gas, which is not useable by plants or animals

• N = critical plant & animal nutrient

  • All living things need N for DNA & amino acids to make proteins

Unit 1 - The Living World - Ecosystems (6-8%): Nitrogen Fixation

• Process of N₂ gas being converted into biologically available (useable by plants) NH₃ (ammonia) or NO₃ (nitrate)

• Biotic fixation

• Abiotic fixation

Unit 1 - The Living World - Ecosystems (6-8%): Biotic Fixation

Certain bacteria that live in the soil, or in symbiotic relationship with plant root nodules convert N₂ into ammonia (NH₃)

(Living things turn N₂ into ammonia NH₃)

• Rhizobacteria live in root nodules of legumes (peas, beans) & fix N for them in return for amino acids from the plant (mutualism)

Unit 1 - The Living World - Ecosystems (6-8%): Abiotic Fixation

Lightning converts N₂ gas into nitrate (NO₃) and FF combustion converts N₂ gas into ammonia (NH₃)

(Lightning turns N₂ into nitrate NO₃ and FF combustion turns it into ammonia NH₃)

• NH₃ is added to synthetic fertilizer and applied to agricultural soils (where it’s converted into nitrate)

Unit 1 - The Living World - Ecosystems (6-8%): Other N Cycle Steps

• Assimilation

• Ammonification

• Nitrification

• Denitrification

Unit 1 - The Living World - Ecosystems (6-8%): Assimilation

Plants & animals taking N in and incorporating it into their biomass

• Plant roots take in NO₃ or NH₃ from soil’ animals assimilate N by eating plants or other animals

Unit 1 - The Living World - Ecosystems (6-8%): Ammonification

Soil bacteria, microbes & decomposers converting waste & dead biomass back into NH₃ and returning it to soil

Unit 1 - The Living World - Ecosystems (6-8%): Nitrification

Conversion of NH₄ and NH₃ into nitrite (NO₂) then nitrate (NO₃) by soil bacteria

Unit 1 - The Living World - Ecosystems (6-8%): Denitrification

Conversion of soil N (NO₃) into nitrous oxide (N₂O) gas which returns to atmosphere

Unit 1 - The Living World - Ecosystems (6-8%): Human Impacts on N Cycle

• Climate

• Leaching & Eutrophication

Unit 1 - The Living World - Ecosystems (6-8%): Climate

N₂O (nitrous oxide) = greenhouse gas which warm earth’s climate

• Produced by denitrification of nitrate in agricultural soils (especially when waterlogged/over watered)

Unit 1 - The Living World - Ecosystems (6-8%): Leaching & Eutrophication

Synthetic fertilizer use leads to nitrates (NO₃) leaching, or being carried out of soil by water

• Nitrates runoff into local waters, causing algae blooms that. block sun & kill other aquatic plants

Unit 1 - The Living World - Ecosystems (6-8%): Phosphorous Cycle Basics

• Movement of P atoms & molecules b/w sources & sinks/reservoir

• Rocks & sediments containing P minerals = major reservoirs

  • P cycle is very slow compared to C/H₂O/N cycles

• Takes a long time for P minerals to be weathered out of rocks & carried into soil/bodies of water

  • No gas phase of P (doesn’t enter atmosphere)

• B/c it cycles so slowly, it is a limiting nutrient, meaning plant growth in ecosystems is often limited by P availability in soil/water

• P is needed by all organisms for DNA, ATP (energy), bone & tooth enamel in some animals

Unit 1 - The Living World - Ecosystems (6-8%): Phosphorous Sources

Major natural source of P is weathering of rocks that contain P minerals

• Wind & rain break down rock & phosphate (PO₄^-3) is released and dissolved into water; rain water carries phosphate into nearby soils & bodies of water

• Weathering is so slow that P is often a limiting nutrient in aquatic & terrestrial ecosystems

Synthetic (human) sources of P = mining phosphate minerals & adding to products like synthetic fertilizers & detergents/cleaners

• Synthetic fertilizers containing phosphates are added to lawns or agricultural fields; runoff carries P into nearby bodies of water

• Phosphates from detergents & cleaners enter bodies of water via wastewater from homes

Unit 1 - The Living World - Ecosystems (6-8%): Assimilation & Excretion/Decomposition

Just like N. P is absorbed by plant roots & assimilates into tissues; animals assimilate P by eating plants or other animals

Animal waste, plant matter & other biomass is broken down by bacteria/soil decomposers that return phosphate to soil

Assimilation & excretion/decomposition form a mini-loop within P cycle just like assimilation & ammonification in N Cycle, photosynthesis & respiration in C Cycle

Unit 1 - The Living World - Ecosystems (6-8%): Sedimentation & Geologic Uplift

Phosphate doesn’t dissolve very well into water; much of it forms solid bits of phosphate that fall to the bottom as sediment (sedimentation)

P sediments can be compressed into sedimentary rock over long time periods by weight of overlying water

Geological uplift

Unit 1 - The Living World - Ecosystems (6-8%): Geological Uplift

Tectonic plate collision forcing up rock layers that form mountains; P cycle can start over again with weathering & release of phosphate from rock

Unit 1 - The Living World - Ecosystems (6-8%): Eutrophication (Too Much N & P)

**Can occur from fertilizer runoff, human/animal waste contamination

B/c they’re limiting nutrients in aquatic ecosystems, extra input of N & P leads to eutrophication (excess nutrients) which fuels algae growth

• Algae blooms covers surface of water, blocking sunlight and kills plants below surface

• Algae eventually die-off; bacteria that break down dead algae use up O₂ in the water (b/c decomposition = aerobic process)

• Lower O₂ levels (dissolved oxygen) in water kills aquatic animals, especially fish

• Bacteria use up even more O₂ to decompose dead aquatic animals

• Creates positive feedback loop: less O₂ —> more dead organisms —> more bacterial decomposition —> less O₂

Unit 1 - The Living World - Ecosystems (6-8%): Decomposition

the natural process where organic matter, like dead plants and animals, is broken down into simpler substances by decomposers like bacteria, fungi, and worms. This process plays a crucial role in nutrient cycling and the breakdown of waste materials. 

Unit 1 - The Living World - Ecosystems (6-8%): Water Cycle Overview

Movement of H₂O (in different states) between sources & sinks

• State of matter (solid/liquid/gas) as well as where water is moving are key in H₂O cycle

  • Ex: precipitation = atmosphere (gas) —> land or surface water (liquid)

• Energy from sun drives the H₂O cycle

  • Ex: heat from sun causes liquid water in ocean to become a gas (evaporation) in atmosphere

• Ocean = largest water reservoir

• Ice caps & groundwater are smaller reservoirs, but contain fresh, useable water for humans

Unit 1 - The Living World - Ecosystems (6-8%): Evaporation & Evapotranspiration

2 main sources of water (process that cycle it from liquid on earth back into the atmosphere)

Sometimes called “vaporization” since liquid water becomes water vapor (gas) in atmosphere

Transpiration

Evapotranspiration

Both processes are driven by energy from the sun

Unit 1 - The Living World - Ecosystems (6-8%): Transpiration

Process plants use to draw groundwater from roots up to their leaves

• Leaf openings called stomata open, allowing water to evaporate into atmosphere from leaf

• Movement of H₂O out of lead creates low H₂O potential in leaf, putting H₂O up from roots

Unit 1 - The Living World - Ecosystems (6-8%): Evapotranspiration

Amount of H₂O that enters atmosphere from transpiration & evaporation combined

Unit 1 - The Living World - Ecosystems (6-8%): Runoff & Infiltration

Precipitation (rain) either flows over earth’s surface into a body of water (runoff or trickles through soil down into groundwater aquifers (infiltration)

• Groundwater (aquifers) & surface waters (lakes/rivers) are important freshwater reservoirs for humans & animals

Precipitation recharges groundwater through infiltration, but only if ground is permeable (able to let water pass through)

Runoff recharges surface waters, but can also carry pollutants into water sources

Unit 1 - The Living World - Ecosystems (6-8%): Percolation

the flow of water through soil and porous or fractured rock (tunnel)

Unit 1 - The Living World - Ecosystems (6-8%): What is the quickest to slowest gas cycle?

1. Water Cycle

2. Nitrogen Cycle

3. Carbon Cycle

4. Phosphorous Cycle

Unit 1 - The Living World - Ecosystems (6-8%): Primary Productivity

Rate that solar energy is converted into organic compounds via photosynthesis over a unit of time

• Aka: rate of photosynthesis of all produces in an area over a given period of time

• Since photosynthesis leads to growth, you can also think of PP as the amount of plant growth in an area over a given period of time

Unit 1 - The Living World - Ecosystems (6-8%): PP Basics

units: kcal/m²/yr.

• kcal = energy

• m² = area

• yr. = time

High PP = high plant growth = lots of food & shelter for animals

Ecosystems with high PP are usually more biodiverse (more diversity of species) than ecosystems with low PP

Unit 1 - The Living World - Ecosystems (6-8%): Calculating PP

NPP = GPP - RL

• NPP = Net Primary Productivity

• GPP = Gross Primary Productivity

• RL = Respiration Loss

Unit 1 - The Living World - Ecosystems (6-8%): Net Primary Productivity (NPP)

The amount of energy (biomass) leftover for consumers after plants have used some for respiration

• Think of NPP as the actual amount of the plant’s paycheck it keeps after taxes

Unit 1 - The Living World - Ecosystems (6-8%): Gross Primary Productivity (GPP)

The total amount of sun energy (light) that plants capture and convert to energy (glucose) through photosynthesis

• Think of GPP as the total paycheck amount the plant earns