APES UNIT 1

APES UNIT 1  ECOSYSTEMS

1.1 

Ecosystem: the interaction of living & non living things

(a specific portion of the world’s environment) 

Environment: the entire natural world

Habitat: the specific environmental condition a certain species needs to survive

Relationships between species:

• Symbiosis is NOT mutualism

• Symbiosis who is living in close proximity

• Mutualism benefits BOTH species (algae & coral reef) 

• Whether one both or neither species benefit with each other 

1.2-1.3

Biome: an area that shares an average annual temperature and average precipitation

 If temperature and precipitation changes, then biomes can shift

Aquatic Biomes: 

1. Salinity/saltiness need to be adapted to the dehydrating effects of salt (like holes/pores) 

2. Flow (disrupts the surface to allow oxygen to diffuse  in the water & carries sediments and gets carries) 

3. Estuaries (unique salinity level -> species that live there they have to be unique adapted & sediments carry nutrients for species)

REMEMBER (organisms living in the biomes are uniquely adapted for those temperature and precipitation)

1.4 

Law of Conservation of Matter 

Matter is never created or destroyed, it only changes forms 

This is VERY important for all the cycles (biogeochemical cycle terminology) 

Reservoirs: Things that temporarily store matter

Sources: Processes that move matter around between reservoirs 

Sinks: Reservoirs that store more matter than they give off 

Carbon Cycle Key Points:

1. Carbon sources return carbon to the atmosphere while sinks remove carbon from the atmosphere 

2. The amount of time carbon spends in different reservoirs significantly varies a lot and that time is important to global climate 

The atmosphere is a critical carbon reservoir because the amount of carbon the atmosphere stores at any  given time determines Earth's global climate. Is carbon being taken out or being taken in?

Photosynthesis: Removes carbon from the atmosphere and stories it in plant life 

Respiration: returns carbon dioxide to the atmosphere as plants and animals break down glucose to use for energy  

The most important carbon cycle step that humans can do is extraction & combustion. We dig up fossil fuels and burn them for electricity -> this returns carbon dioxide to the atmosphere that was out of circulation for millions and millions of years.  This is why the rate of carbon cycling is so important. You are putting way more carbon dioxide in the atmosphere than you’re saving 

Nitrogen Cycle:

• The movement of nitrogen between reservoirs 

• Key Point: Nitrogen is cycling far more quickly through its reservoirs in the carbon cycle 

• Key Point: The Major Nitrogen reservoir is the atmosphere (nitrogen in the atmosphere exists in a form that’s biologically unavailable to plants or animals because the triple bond between these nitrogen atoms in its gas phase is just too strong to be broken apart by plants or animals)

• Nitrogen Fixation: converts biologically unavailable nitrogen gas (N2) into biologically available form 

• The main way that nitrogen is fixed in the natural world is by bacteria with specialized enzymes that can break apart these strong triple binds and pair up those nitrogen atoms with hydrogens forming ammonia can be done in root nodules or soil 

• Fixed by extreme energy or fossil combustion 

• Animals cannot assimilate nitrogen without nitrogen fixation

Phosphorus cycle:

• Def: No gas phase, doesn't enter atmosphere, making it slow than other cycles 

• Key Point: the major phosphorous  reservoirs are rocks and sediments that contain phosphorus based minerals so unlike carbon and nitrogen which are bouncing all over the atmosphere as gas molecules, Phosphorus is just stuck in rocks and for phosphorus to be released from those rocks those rocks have to undergo weathering 

• Vocab: Weathering is the breakdown of rocks by process like _> smaller and smaller pisces that releases phosphate in the form of phosphate ions 

• Key point: Phosphorus travels through runoff and between ecosystems and is often the limiting factor of plant growth

• Often plants don't have enough phosphorus due to location + other reasons

1.7 The Water Cycle (rewatch this when you do flashcards sep video)

• IMPT: The process of the water cycle is driven by the sun & its energy

• Water evaporates from a body of water like a lake or river. It's because the sun has given that water enough energy to actually convert it from a liquid to a gas phase. When it rains, it’s because the moisture in the air has reached a condensation point based on the temperature of that layer in the atmosphere which it’s also based on the sun's energy

• Vocab: Infiltration is water seeping through the soil and recharging ground water reservoirs. It is the process of precipitation or surface water seeping into or seeking down through the layers of the soil into groundwater.

• Vocab: Transpiration is water evaporating from the leaves stomata and entering the atmosphere in the gas phase (also rewatch this part)

• IMPT: the ocean is the major water reservoir but this water is not usable for humans so other freshwater reservoirs like groundwater or polar ice caps or water stored in rivers/lakes is really critical for us to use but unfortunately sometimes we can’t

Book points about the water cycle: 

• The rate of evaporation equals the rate of precipitation 

• Process involved in the water cycle:

• Condensation, evaporation, evapotation, infiltration, precipitation, runoff 

1.8 Primary Productivity= (rate of photosynthesis) (reread this in the book) 

• Important Vocabulary: Primary productivity is The rate at which plants in an area convert sunlight into glucose or plant tissue (photosynthesis) 

• Formula of Primary productivity is  energy/area/time

• It's like knowing how much money you make per hour of a job = rate

• Respiration Loss: the energy plants use up for their own cellular respiration 

• Know This meaning:

• Okay so Gross Primary Production is the total amount of energy that plants produce but net primary production is the amount of energy that plants can actually store after they’ve given up what they need for cellular respiration. We can calculate the gross primary productivity & the net primary productivity (or the respiration loss ) using the simple equation NPP = GPP - RL

1.9-1.10 Trophic Levels/Energy Flow 10% Rule 

• Vocab:

•  Trophic Pyramid -> shows how much energy flows through different levels in a food chain 

• Second Law of Thermodynamics: Some energy is lost as heat each time energy is transferred 

• 10% rule; only 10% of energy is transferred to the next level

1.11 Food webs 

• The arrows in a food chain or food web show the movement of both energy and matter

• Important to know that the removal of one species can have great effect on the organism in the rest of the food web