%%1.1 Ecosystems%%
Learning Objective
- Explain how the availability of resources influences species interactions
Ecosystem Basics
- Individual (elk)
- Population (elk herd)
- group of individuals of same species
- Community
- all living organisms in an area
- @@Ecosystem@@
- all living and nonliving things in an area
- Ex. plants, animals, rocks, soil, water, air
- @@Biome@@
- large area with similar climate conditions that determines the plant and animal species that live will there
- Ex. tropical rainforest
Organism Interactions
@@Competition@@
- Organisms fighting over a resource like food or shelter
Reduces population size since there are fewer resources available and fewer organisms can survive
Resource partitioning - different species using the same resource in different way to reduce competition
Temporal partitioning - using resources at different times
- wolves and coyotes hunting at different times
Spatial partitioning - using different areas of a shared habitat
Morphological partitioning - using different resources based on different evolved body features
@@Predation@@
- One organism using another for energy (hunters, parasites, even herbivores)
- Herbivores (plant eaters) eat plants for energy
- Ex. giraffe and tree
- True predators (carnivores) kill and eat prey for energy
- Ex. leopard and giraffe
- Parasites use a host for energy often without killing the host and whilst living inside the host
- Ex. mosquitoes, tapeworms, sea lamprey
- Parasitoids lays eggs inside hosts which hatch and eat the host for energy
- Ex. parasitic wasps, bot fly
@@Symbiosis@@
- Any close and long-term interaction between two organisms of different species
Mutualism - Both organisms benefit from the relationship (coral reef)
- Coral provide reef structure and CO2 for algae who provides sugars for coral to use as energy
- Lichen is a composite organism of fungi living with algae and algae provide sugars and fungi provides nutrients
Commensalism - One organism benefits from the relationship while the other is not impacted (birds nest in trees)
1.2 Terrestrial Biomes
Learning Objective
- Describe the global distribution and principal environmental aspects of terrestrial biomes
Biome
- an area that shares a combination of average yearly temperature and precipitation
Note: Latitude (distance from equator) determines temperature and precipitation which is why biomes exist in a predictable pattern on earth.
Tundra and Boreal - Higher Latitude (60 degrees +)
Temperate - Middle Latitude (30 - 60 degrees)
Tropical - closer to the equator
Nutrient Availability
Plants need soil nutrients to grow, so availability determines which plants can survive in a biome
- @@Tropical Rainforest@@
- nutrient poor soil
- high competition from so many different plant species
- @@Boreal Forest@@
- nutrient poor soil
- low temperature
- low decomposition rate of dead organic matter
- @@Temperate Forest@@
- nutrient rich soil
- lots of dead organic matter
Shifting Biomes
- Biomes shift in location on earth as climate changes
1.3 Aquatic Biomes
Learning Objective
- Describe the global distribution and principal environmental aspects of aquatic biomes
Characteristics
Salinity
- How much salt there is in a body of water
- determines which species can survive and usability for drinking
Depth
- Influences how much sunlight can penetrate and reach plants below the surface for photosynthesis
Temperature
- Warmer water holds less dissolved oxygen so it can support fewer aquatic organisms
Flow
- How much oxygen can dissolve into water
- Determines which plants and organisms can survive
Freshwater
Rivers
- have high oxygen due to flow mixing water and air
- also carry nutrient rich sediments
Lakes
- standing bodies of freshwater
- Littoral Zone - shallow water with emergent plants
- Limnetic Zone - where light can reach
- Profundal Zone - too deep for sunlight
- Benthic Zone - murky bottom where inverts live, nutrient rich sediments
Wetlands
- area with soil submerged or saturated in water for at least part of the year, but shallow enough for emergent plants
Note: Plants living here have to be adapted to living with roots submerged in standing water
Benefits of Wetlands
- Stores excess water during storms, lessening floods
- Recharges groundwater by absorbing rainfall into soil
- Roots of wetland plans filter pollutants from water draining through
- High plant growth due to lots of water and nutrients in sediments
Estuaries
Estuaries are areas where rivers empty into the ocean
- mix of fresh and salt water
- high productivity (plant growth)
Types of Estuaries
- Salt Marsh
- Estuary habitat along coast in temperate climates
- Breeding ground for many fish and shellfish species
- Mangrove Swamps
- Estuary habitat along coast of tropical climates
- Mangrove trees with long, stilt roots stabilize shoreline and provide habitat for many species of fish and shellfish
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 & provide sugar (energy) to the coral through photosynthesis
Intertidal Zones
Narrow band of coastline between high and low tide
- Organisms must be adapted to survive crashing waves & direct sunlight/heat during low tide
- Different organisms are adapted to live in different zones
Open Ocean
- low productivity
- so large that the ocean produce a lot of the earth’s oxygen and absorbs a lot of carbon dioxide
Photic Zone
- area where sunlight can reach
Aphotic Zone
- area too deep for sunlight
%%1.4 Carbon Cycle%%
Learning Objective
- Explain the steps and reservoir interactions in the carbon cycle
Overview
Movement of molecules that contain Carbon (CO2, glucose, CH4) between sources and sinks
Some steps are very quick (FF combustion); some are very slow (sedimentation & burial)
Leads to imbalance in which reservoirs or sinks are storing carbon
Atmosphere is a key carbon reservoir
- increasing levels of carbon in atmosphere leads to global warming
Sinks and Sources
- Carbon sink: a carbon reservoir that stores more carbon than it releases \n â—‹ Ocean (algae & sediments), plants, soil
- Carbon source: processes that add C to atm. \n â—‹ Fossil fuel (oil, coal, natural gas) combustion \n â—‹ Animal ag. (cow burps & farts = CH4) \n â—‹ Deforestation, releases CO2 from trees
Photosynthesis and Cellular Respiration
Photosynthesis (Carbon Sink)
Removes CO2 from the atmosphere and converts it to glucose
- Glucose
- biological form of carbon
- stored energy in form of sugar
Cellular Respiration (Carbon Source)
Uses oxygen to break glucose down and release energy (Done by plants and animals to release stored energy). Releases carbon dioxide into atmosphere
Both processes are very quick and cycle carbon between biosphere and atmosphere in balanced amount
Ocean and Atmosphere
Direct exchange
- CO2 moves directly between atmosphere & the \n ocean by dissolving into & out of ocean water at the surface
- Happens very quickly & in equal directions, balancing levels of CO2 between atm. & ocean.
- Because of direct exchange, increasing atm. CO2 also increases ocean CO2, leading to ocean acidification \n Sedimentation
- when marine org. die, their bodies sink to ocean \n floor where they’re broken down into sediments that contain C
Burial, Extraction, and Combustion
Burial
- slow, geological process that stores C in underground sinks \n like sedimentary rock or fossil fuels
- Sediments (bits of rock, soil, organic matter) compressed into sed. rock, or \n FF, by pressure from overlying rock layers or water
Fossil Fuels (FF):
- coal, oil, and Nat. gas are formed from fossilized remains of org. matter.
Extraction & Combustion
- digging up or mining FFs & burning them as energy source; releases CO2 into atm.
Burial (formation of FFs) takes far longer than extraction & combustion, which means they \n increase concentration of CO2 in atmosphere
%%1.5 Nitrogen Cycle%%
Learning Objective
- Explain the steps and reservoir interactions in the Nitrogen Cycle
Nitrogen Cycle Overview
Movement of nitrogen-containing molecules between sources and sinks
Note: Atmosphere is the main reservoir
- Nitrogen is a critical plant and animal nutrient
Nitrogen Fixation
Process of N2 gas being converted into biologically available ammonia or nitrate
- Bacterial Fixation
- certain bacteria that live in the soil, or in symbiotic relations with plant root nodules convert N2 into ammonia
- Ex. Rhizobacteria live in root nodules of legumes \n (peas, beans) & fix N for them in return for \n amino acids from the plant
- Synthetic Fixation
- humans combust FFs to convert N2 gas into nitrate
More N Cycle Steps
- Assimilation
- plants and animals taking N in and incorporation it into their body
- Ammonification
- soil bacteria, microbes, and decomposers converting waste and dead biomass back into ammonia and returning it to soil
- Nitrification
- conversion of NH4 into nitrite and then nitrate by soil bacteria
- Denitrification
- conversion of soil N into nitrous oxide gas which returns to the atmosphere
Human Impacts
- Climate
- Nitrous oxide (a greenhouse gas) warms the earth’s climate
- Ammonia Volatilization
- excess fertilizer use can led to ammonia gas entering the atmosphere
- can lead to acid raid and respiratory irritation for humans and animals
- Leaching
- synthetic fertilizer use leads to nitrates leaching or being carried out of soil by water
%%1.6 Phosphorus Cycle%%
Learning Objective
- Explain the steps and reservoir interactions in the phosphorus cycle
Phosphorus Cycle Basics
Movement of phosphorus atoms and molecules between sources and sinks (very slow compared to other cycles)
- no gas phase
- because it cycles so slowly, phosphorus is a limiting nutrient
- this means that plant growth in ecosystems is often limited by phosphorus availability
Note: rocks and sediments containing phosphorus are major reservoirs
Phosphorus Sources
Major natural source of P is weathering of rocks that contain P minerals.
- Wind & rain break down rock & phosphate is released and dissolved into water; rain water carries phosphate into nearby soils & bodies of water
Synthetic (human) sources of P
- mining phosphate minerals & adding to products like synthetic fertilizers & detergents/cleaners
Assimilation and Excretion
Phosphorus is absorbed and assimilated into tissues for plants, animals assimilate by eating plants or other animals
Phosphorus is excreted through animal water, plant matter, and other biomass that is broken down by decomposers that return phosphate to the soil
Sedimentation and Geological Uplift
Sedimentation
- Phosphate doesn’t dissolve well in water and will form solid bits that fall to the bottom of water as sediment which can be compressed into rock over long periods of time
Geological Uplift
- tectonic plate collision forcing up rock layers that form mountains; P cycle can start over again with weathering and release of phosphate from rock
Eutrophication
The excess of nutrients
- fuels algae growth and can lead to a positive feedback loop
Algae blooms → Surface of Water becomes blocked → Sunlight does not reach plants killing them → Algae dies→ Decomposers use up oxygen in water to break down algae → Low Oxygen Levels kills fish → More Decomposers Use More Oxygen
1.7 The Hydrologic Cycle
Learning Objective
- Explain the steps and reservoir interactions in the hydrologic cycle
Water Cycle Overview
Movement of water between sources and sinks. States of matter as well as where water is moving are key in the water cycle.
Note: the ocean is the largest water reservoir whilst ice caps and ground water are some of the smallest (this water is fresh and useable for humans)
Evaporation
Sometimes called vaporization, is the process in which liquid water becomes water vapor (gas) in the atmosphere. (driven by the sun)
Transpiration
- process plants use to draw ground water from roots up to their leaves (driven by the sun)
Evapotranspiration
- amount of water that enters the atmosphere from transpiration and evaporation combines
Runoff
- rain that flows over earth’s surface and into a body of water
Recharges surface waters but can also carry pollutants into water sources.
Infiltration
- rain that trickles through the soil down into groundwater reservoirs
Recharges groundwater with rain but only if the ground is permeable.
- Permeable
- able to let water pass through
1.8 Primary Productivity
Learning Objective
- Explain how solar energy is acquired and transferred by living organisms
Primary Productivity Basics
units: kcal/m^2/yr
Primary Productivity
- rate that solar energy is converted into organic compounds via photosynthesis over a unit of time
- rate of photosynthesis of all producers in an area over a given period of time
High PP
- high plant growth
- lots of food and shelter for animals
Ecosystems with high PP are usually more biodiverse than ecosystems with low PP
Calculating PP
Net Primary Productivity
- the amount of energy (biomass) leftover for consumers after plants have used some for respiration
Gross Primary Productivity
- The total amount of sun energy (light) that plants capture and convert to energy (glucose) through photosynthesis
Respiration Loss
- Energy used up for respiration
Ecological Efficiency
- The portion of incoming solar energy that is captured by plants and converted into biomass
Note: Some ecosystems are more efficient than others
Trends in Productivity
- the more productive a biome is, the wider the diversity of animal life it can support
Water availability, higher temperature, and nutrient availability are all factors that lead to high NPP
- shortage of any of these factors will lead to decreased NPP
^^1.9 Trophic Levels^^
^^Learning Objective^^
^^Explain how energy flows and matter cycles through trophic levels.^^
^^Trophic Levels^^
- ^^Tertiary Consumers^^
- ^^animals that eat secondary consumers or carnivores and omnivores^^
- ^^Secondary Consumers^^
- ^^animals that eat primary consumers or herbivores^^
- ^^Primary Consumers^^
- ^^animals that eat plants^^
- ^^Producers^^
- ^^plants “produce” (convert) sun’s light energy into glucose^^
^^1.10 Energy Flow and the 10% Rule^^
^^Learning Objective^^
- ^^Determine how the energy decreases as it flows through ecosystems^^
^^Conservation of Matter and Energy^^
^^Matter & energy are never created or destroyed; they only change forms^^ \n ^^1st law of thermodynamics:^^
- ^^energy is never created or destroyed^^
^^2nd law of thermodynamics:^^
- ^^each time energy is transferred, some of it is lost as heat^^
^^Biogeochemical cycles demonstrate conservation of matter (C/N/H2O/P)^^
^^Food webs demonstrate conservation of energy^^
^^10% Rule^^
- ^^in trophic pyramids, only about 10% of the energy from one level makes it to the next level; the other 90% is used by the organism & lost as heat^^
^^1.11 Food Chains and Food Webs^^
Learning Objective
- Describe food chains and food webs, and their constituent members by trophic level
Food Web Basics
Shows how matter and energy flow through an ecosystem, from organism to organism
- Arrows in food webs indicate direction of energy flow
Food Web v Food Chain
Food chains just show one, linear path of energy and matter
Food webs have at least 2 different interconnected food chains
Interactions and Trophic Cascade
Food webs show how increase or decreases in population size of a given species impact the rest of the food web
Trophic Cascade
- removal or addition of a top predator has a ripple effect down through lower trophic levels