Intro to Ecosystems - (2/13 - 2/17)

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Summary: 

     An ecosystem is the interaction of biotic (living) and abiotic (non-living) things. For example, many animals which are biotic require water which is a non-living thing to survive. This is one example of how biotic and abiotic things interact. There are also systems in an ecosystem. The Carbon Cycle is how carbon is used and recycled. Carbon comes from the atmosphere. It goes to the plants for photosynthesis and then to the animals that eat the plants. It eventually returns to the atmosphere through cellular respiration/photosynthesis. The Nitrogen Cycle is how nitrogen is used and recycled. Like carbon, it comes from the atmosphere but instead of going directly to the plants, it is first turned into nitrates by bacteria in order to be usable. It is then passed on to the animals that eat the plants. When the animals die, it goes to the decomposers. From that point on, it either goes back to the plants or it goes through denitrifying bacteria which turns the nitrates back into nitrogen which returns to the atmosphere.

SP3 - Conducting Investigations:

     This week I conducted many investigations to see what would happen if a certain organism disappeared, underpopulated, or overpopulated in an ecosystem. I identified my variables and controls, which was the population of the organisms and whether they were diseased or not. I designed and performed experiments to test my hypotheses. One of my hypotheses was that removing approximately 3/4 the hawk population would make the ecosystem of hawks, snakes, rabbits, and grass nearly collapse, but then recover back to normal. When I tested this out, I saw on the graph that the snake population increased which made the rabbit population decrease which made the grass population increase. It then reversed to the snake population lowering to the rabbit population increasing then to the grass population decreasing. Eventually, everything balanced out since there was an eventual increase in snakes which gave the hawks the opportunity to grow.  

XCC -  Stability and Change:

     The system I will be identifying is the energy pyramid of the ecosystems. This system involves producers which are plants, primary consumers which are the animals that eat the plants, the secondary consumers which consume the primary consumers, and the third level consumers which eat the secondary consumers. For this system, I will ignore the apex consumers. The energy pyramid system is normally stable by default. However, it can turn unstable if there is a lack of any of these consumers. For example, if there was very little producers, that would mean the primary consumers that eat the plants would die off, which means that the secondary consumers would also die off, meaning the third level consumers would as well, die off. But since there is a lack of primary consumers to eat the producers, that means that the producers would have a chance to grow, which means that the primary consumers would grow in population and so on. If there is ever a lack of a consumer/producer in an ecosystem, the ecosystem will go unstable, but has a good chance of re-stabilizinghj as seen in this example as long as the consumer/producer doesn't go fully extinct in the area. If that were to happen, everything would die off.