There are many types of relationships in environmental science.
Predator-prey relationships are when a predator, such as a lion, eats his prey, such as a gazelle.
Symbiosis is the relationship between two species that have a close and long-term interaction with one another.
There are many types of symbiosis: mutualism, commensalism, and parasitism.
Commensalism is another relationship between species when one organism benefits and the other neither benefits nor is harmed.
Parasitism is the final example of symbiosis. In this relationship, one species benefits while the other is harmed.
Another type of relationship is competition, when two or more species (or between members of the same species) are all competing for the same, usually limited, resource.
These limited resources are often food, water, or territory.
As seen in Figure 5.2, carbon is found in the land, water, and atmosphere.
A carbon sink is where carbon is stored, for example in plants, the ocean, and soil.
Photosynthesis and cellular respiration are how carbon cycles in living things and is known as short-term cycling.
Like carbon, nitrogen cycles between sources and sinks (Figure 5.3).
The steps of the nitrogen cycle can be easily memorized by a mnemonic device known as FixNAAD ANPAN (Table 5.1).
As you can see from the chart, the nitrogen cycle relies heavily on bacteria to cycle it between land, water, and the atmosphere. It is a relatively fast cycle.
Table 5.1
Process | Product | Explanation |
---|---|---|
Fix—Nitrogen Fixation | A—Ammonia | During nitrogen fixation, N2 from the atmosphere is converted by nitrogen-fixing microorganisms into ammonia. |
N—Nitrification | N—Nitrites/Nitrates | During nitrification, bacteria convert ammonia into nitrites and then nitrates. |
A—Assimilation | P—Proteins (DNA/Amino Acids) | During assimilation, nitrates are then converted into plant proteins, and nucleic acids that animals can then get from the plant tissues. |
A—Ammonification | A—Ammonia | Ammonification is the process where decomposers take plant and animal cells and return the nitrogen back to the soil in the form of ammonia. |
D—Denitrification | N—Nitrogen Gas | Bacteria convert nitrogen in the soil back to an atmospheric form. |
The phosphorus cycle is a slow cycle and it does not have an atmospheric form; phosphorus is only found on the land and in the water (Figure 5.4).
The water cycle is the process in which water moves from the atmosphere to the oceans/lakes/rivers to the land (Figure 5.5).
The major steps include evaporation, condensation, runoff, precipitation, transpiration, and infiltration.
Water on our planet is found in three phases: solid (ice or snow), liquid (rainfall or water in lakes), and gas (in the atmosphere).
The majority of water on our planet is found in the oceans, which cover approximately 70% of the Earth.
Once again, all energy comes from the sun but it can be converted from one form to another.
The first trophic level are the plants, or primary producers. These are then eaten by primary consumers (the second trophic level) and so forth up the pyramid.
A food chain is a visual representation of how organisms depend on one another for a source of food with arrows pointing from the organism that is being eaten to the organism that eats it and receives the energy from it (Figure 5.7).
A food web is a visual representation of many food chains put together and is more like real life because it shows the complexity of feeding relationships in the system (Figure 5.8).
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