APES Test 2 Ecosystem Slides Midterm Review Flashcards
Ecosystem Definition
A biological community of interacting organisms and their physical environment.”
Biological community: an interacting group of various species in a common location.
interaction between abiotic and biotic factors structures ecosystems
Things like……
Weather/Climate
Soil Type
Topography
Natural Features (Rivers, Lakes, Oceans, etc.)
Influence what plants and animals can live in an ecosystem
Symbiosis is a close and long-term interaction between two species in an ecosystem. Types of symbiosis include:
Mutualism: Both Benefit
Commensalism: One Benefits
Parasitism: One Benefits, One is Harmed
Competition
Competition can occur within or between species in an ecosystem where there are limited resources.
Resource partitioning
using the resources in different ways, places, or at different times—can reduce the negative impact of competition on survival.
Niche
the role an organism plays in an ecosystem- is usually similar between competitors in some aspect- but not always
Biomes
Geographical region characterized by specific climatic conditions, flora and fauna.
You need to know the biomes and their general climate conditions (wet/dry, warm/cold, seasons, etc.)
A biome contains characteristic communities of plants and animals that result from, and are adapted to, its climate.
Biomes are recognizable places if you know what you are looking for, because they have a specific community of organisms.
The worldwide distribution of biomes is dynamic; the distribution has changed in the past and may again shift as a result of global climate changes.
Range loss and range change……sound familiar??
Biomes can shift to new areas as climatic conditions change
Ice Age ~ 25,000 years ago- we had glaciers here, boreal forest, and even some tundra
A lot changes in a short period of time!
Freshwater biomes include streams, rivers, ponds, and lakes. These freshwater biomes are a vital resource for drinking water.
97% water= saltwater
Very little fresh water on earth
Desalination is expensive- drinking water is critical for human and ecosystem survival
Streams and Rivers- discharge water, narrow and long, flow (generally N- S)
Ponds and Lakes- stores of water, usually discharged by streams and rivers
marine biomes
Marine biomes include oceans, coral reefs, marshland, and estuaries. Algae in marine biomes supply a large portion of the Earth’s oxygen, and also take in carbon dioxide from the atmosphere.
Know these different types and memorize them.
Recognize that critical role that algae play in providing oxygen for the planet
The global distribution of nonmineral marine natural resources, such as different types of fish, varies because of some combination of salinity, depth, turbidity, nutrient availability, and temperature.
Salinity- varies by depth temperature. Different organisms have different tolerances
Turbidity- clarity of the water (amount of light that can pass through). Note amount of light itself also varies with depth.
Nutrient Availability- depends on organisms and ecological community, terrestrial inputs are relatively insignificant
Temperature: Varies considerably with latitude and depth; ocean currents can circulate heat and break this relationship to some degree
The Nitrogen Cycle
Nitrogen starts in the atmosphere as Nitrogen Gas (N2)- it comprises about 78%!
This nitrogen is poorly reactive and not useful to organisms
It must be fixed- by nitrogen fixing bacteria, to become biologically available
Nitrogen Fixation
Biological demand for nitrogen is high, but N2 gas is useless to plants
Bacteria, often in the root nodules of legumes, can ‘fix’ nitrogen gas
Nitrogenase (enzyme) ——> Nitrogen gas to ammonia
Ammonia is more biologically available, but can be ‘fixed’ further to other forms
Lightning can also fix nitrogen, but this accounts for <10%
Ammonia is the product of nitrogen fixation
Nitrifying bacteria can ‘nitrify’ ammonia into nitrites and nitrates
NO2- (nitrite) and NO3- (nitrate) are different forms of biologically available nitrogen and are useful to a wide range of plants- but nitrates are broadly a much more useful form of nitrogen
NO3 (nitrate) is now able to be used by plants- assimilation is the absorption of nitrogen into plants as nitrate
Animals eat plants that have incorporated nitrates into their tissue
Animals die, and ammonification (mineralization), a part of the decomposition process, breaks this nitrogen down into ammonia or ammonium ions
Ammonium is nitrified into nitrite and then nitrate
Nitrogen can reenter the atmosphere from the terrestrial realm by the process of denitrification- also performed by bacteria
Ammonia is converted back into nitrites and nitrates, then into nitrogen gas and nitrous oxide gas
Nitrogen is a limiting nutrient for NPP and plant growth- some plants require much more of it than others
PHosphorus Cycle
Phosphorus in small amounts is critical for plant growth via cell division
Phosphorus is found mostly in rocks (naturally) and can enter ecological systems via volcanoes and leaching from rocks/sediments
Fertilizer often contains phosphorus which can runoff in excessive quantities
For the most part, phosphorus is found in soil, rock, and sediments; it’s released from these rock forms through the process of chemical weathering
Phosphorus is usually released in the form of phosphate, which is soluble and can be absorbed from the soil by plants
Symbiotic relationships that form between fungi and plants are known as mycorrhizae
In these relationships, mycorrhizal fungi colonize the root system of a host plaint which increases the water and nutrient absorption capabilities of the plant, while the plant provides the fungi with carbs formed from photosynthesis
Phosphates that enter the water table and travel to the pecans can eventually be incorporated into rocks in the ocean floor
Through geologic processes, ocean mixing, and upwelling, these rocks from the seafloor may rise up so that their components once again enter the terrestrial cycle
Water Cycle
Sun drives processes via thermal energy; oceans, glaciers, and lakes can be major sinks
Water that exists in the atmosphere is in a gaseous state, and when it condenses from the gaseous state to form a liquid or solid, it becomes dense enough to fall to the Earth because of the pul of gravity
This process is formally known as precipitation
When precipitation falls onto the Earth, it may infiltrate the surface and percolate through soil and rock until it reaches the water table to become groundwater, or it may travel across the land’s surface as runoff and enter a drainage system, such as a stream or river, which will eventually deposit it into a body of water such as a lake or an ocean
Lakes and oceans are reservoirs for water
In certain cold regions of the Earth, water may also be trapped on the Earth’s surface as snow or ice; in these areas, the blocks of snow or ice are reservoirs
Water also cycles through living systems ex. Plants consumer water (and carbon dioxide) in the process of photosynthesis, in which they produce carbohydrates and oxygen
Because all living organisms are primarily made up of water, they act as exchange pools for water
Water is returned to the atmosphere from both the EArth’s surface and from living organisms in a process called evaporation
Specifically, animals respire and released water vapor and additional gases to the atmosphere
In plants, the process of transpiration releases large amounts of water into the air
Finally, other major contributors to atmospheric water are the vast number of lakes and oceans on the Earth’s surface
Incredibly large amounts of water continually evaporate from their surfaces
Carbon Cycle
Long and short term processes; ‘fast’ and ‘slow’ carbon cycles work together
High amounts carbon typically stored in long term sinks- like limestone, shale (oil), peat
Geological Carbon Cycle
Fast carbon cycle, biological- carbon from atmosphere is photosynthesized by plants, accumulates in soils; decomposition and respiration return carbon to atmosphere
Ocean can dissolve atmospheric carbon dioxide into carbonic acid, which can be used by phytoplankton for photosynthesis; some accumulates in deep ocean sediments where it will eventually lithify into rock (limestone)
