This doc is 76 pages long and goes over the major points of each lesson in AP Environmental Science using the Environmental Science for AP Textbook by Andrew Friedland and Rick A. Relyea. I created and used it to study for the APES exam at the end of my sophomore year and it definitely helped conso...
● competitive exclusion principle: two species competing for the same limiting resource
cannot coexist
● competition: the struggle of individuals, either within or between species, to obtain a
shared limiting resource
○ over time, competition for a resource can cause natural selection to favor those
individuals that have reduced overlap in resource use
● resource partitioning: when two species evolve to divide a resource based on differences
in their behavior or morphology
○ ex: warblers (birds)
● symbiosis: two species living in a close and long-term association with one another in an
ecosystem
○ predation: one animal typically kills and consumes another animal
■ predator-prey relationships are related, as the predator population lags
behind the prey population
● ex: wolves and deer
○ parasitism: one organism lives on or in another, referred to as the host
■ pathogen: a parasite that causes disease in its host
○ mutualism: two species benefit
■ ex: bees pollinating flowers
○ commensalism: one species benefits, while the other is unaffected
■ ex: orchids on a canopy
● ecosystem boundaries are typically characterized by topography
● intraspecific competition: within a species
● interspecific competition: between different species
1.2 Terrestrial Biomes
● biomes are categorized by their seasonal temperature and rainfall, as well as the
dominant plant forms that exist in that region
○ temperature and precipitation → vegetation → animals → biome
● tundra: a cold and treeless biome with low-growing vegetation and the shortest growing
season
● permafrost: an impermeable, permanently frozen layer of soil that typically occurs in
tundra and boreal biomes
● taiga/boreal forest: a forest biome made up primarily of coniferous evergreen trees that
can tolerate cold winters and short growing seasons
● temperate rainforest: a coastal biome typified by moderate temperatures and high
precipitation
● temperate seasonal forest: warm summers and cold winters with over 1 m of annual
precipitation
, ● shrubland: hot, dry summers and mild, rainy winters
● temperate grassland: cold, harsh winters, and hot, dry summers
● tropical rainforest: warm and wet; little seasonal temperature variation and high
precipitation leads to highest primary productivity
● savanna: warm temperatures and distinct wet and dry seasons
● desert: hot temperatures, extremely dry conditions, and sparse vegetation
1.3 Aquatic Biomes
● freshwater biomes: less than 1% salinity; includes streams, rivers, lakes, ponds, and
wetlands
○ wetlands perform a regulating service as they filter water
● littoral zone: shallow zone of soil and water in lakes and ponds near the shore where
most algae and emergent plants (such as cattails) grow
● limnetic zone: a zone of open water in lakes and ponds as deep as the sunlight can
penetrate
● benthic zone: muddy bottom of a lake, pond, or ocean beneath the limnetic and
profundal (aphotic) zones
● types of lakes include…
○ oligotrophic: low amount of nutrients in water
○ mesotrophic: moderate amount of nutrients in water
○ eutrophic: high amount of nutrients in water
■ may cause algal blooms that decrease DO (dissolved oxygen) levels for
other marine organisms
● rivers and streams are lotic (flowing), while ponds and lakes are lentic (standing)
● coral reefs: carbon sink (calcium carbonate)
● estuary: freshwater from rivers mixes with salt water from the ocean
● photic zone: receives sunlight so that photosynthesis can take place
○ aphotic zone: no sunlight; 200 m down
1.4 Carbon Cycle
● aerobic respiration: cells convert glucose and oxygen into energy, carbon dioxide, and
water
● sources of carbon include…
○ combustion of fossil fuels
○ decomposition
○ respiration
○ oceans
● sinks of carbon include…
○ photosynthesis
○ forests
○ fossils underground
, ● decomposition → deposition → sedimentation → fossil fuels (sink) → combustion
(source)
● assimilation of glucose (organic compound) by plants as it is used in photosynthesis
1.5 Nitrogen Cycle
● nitrogen fixation: nitrogen gas is converted to forms of nitrogen that plants can use
○ nitrogen-fixing bacteria
■ thrive in legumes because they have a mutualistic relationship
○ usable forms of nitrogen are nitrate and ammonium
● nitrification: the conversion of ammonia into nitrite, and then nitrate
● denitrifying bacteria: conversion of nitrate into gases (nitrous oxide), and eventually
nitrogen gas that is emitted into the atmosphere
● assimilation occurs as organisms use nutrients from nitrogen to grow
1. 6 Phosphorus Cycle
● phosphorus is a limiting factor and differs from the other cycles because it is not
occurring in the atmosphere
● phosphorus in organic compounds → animals that decompose and form detritus in the
soil → taken up by detritivores and they decompose as well → phosphates in soil →
phosphates in solution (water source) → precipitated (solid) phosphates → rock →
uplifting of rock → weathering of rock → phosphates in soil from rock → phosphates in
organic compounds
● leaching: occurs when water and dissolved nutrients percolate through soil and reach
groundwater
● assimilation occurs as phosphorus is used in ATP formation
1.7 Hydrologic (Water) Cycle
● ice caps and glaciers have the purest freshwater
○ only about three percent of Earth's water is freshwater
● transpiration: release of water from leaves into the atmosphere during photosynthesis
1.8 Primary Productivity
● primary productivity: the rate of converting solar energy into organic compounds over a
period of time
● net primary productivity = gross primary productivity - respiration
1.9 Trophic Levels
● producer → herbivore/primary consumer → secondary consumer → tertiary consumer
● decomposers are also important in breaking down waste from dead animals
, ○ crucial to soil health and nutrient cycling
1.10 Energy Flow and the 10% Rule
● 10% rule: of the total biomass available at a given trophic level, only about 10% of can be
converted into energy at the next higher trophic level
● 1st Law of Thermodynamics: energy cannot be created or destroyed, but can be
transferred
● 2nd Law of Thermodynamics: energy moves towards entropy (chaos)
1.11 Food Chains and Food Webs
● food chain: a sequence of consumption from producers through tertiary consumers
● food web: a model of how energy and matter move through two or more interconnected
food chains
○ aquatic food webs are typically much more extensive than terrestrial food webs
● positive feedback loop: when a small change to a system increases the magnitude of
disturbance later; may destabilize a population
● negative feedback loop: when an increase in output inhibits output later; self-regulates
and slows down
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