Go to the following web link- http://media.hhmi.org/biointeractive/click/trophiccascades/?_ga=2.71133017.874546303.1495559246-1279517233.1480957413
Complete the first slides of the introduction. Next, follow the first example of sea otters, and answer the following questions.
The otter eats the sea urchins and the sea urchins eat the kelp where the otters and the sea urchins are attracted and for this reason there is not much kelp.
The otters were being overhunted which means less sea urchins being consumed. Though, the more sea urchins consuming the kelp which makes the kelp forest start disappearing.
The gull diet change from mainly fish to mainly invertebrates due to the absence of otters.
The eagle diet change from mainly fish and mammals to mainly birds due to the absence of otters.
Choose 1 of the case studies provided and write a summary of what happens when the top predator is present, including all direct, indirect, positive and negative effects at all levels. Discuss what happens when the top predator is removed. (8 points)
The bass is the top predator and it prey on minnows so the minnows decreased because of the presence of the bass. The presence of the minnows also decreased zooplankton populations. Then the zooplankton has a negative effect on phytoplankton because of the presence of zooplankton and they feed on phytoplankton so amount of phytoplankton decreased. However, the phytoplankton has a positive effect on carbon influx from the atmosphere into lakes because it fixes carbon through photosynthesis to dissolve carbon dioxide and the result of the atmosphere has an influx of carbon dioxide when the carbon dioxide in water reduced. Therefore, when the bass is removed, it became an indirect control of the amount of phytoplankton. The bass can alter the balance between the atmospheric carbon dioxide and the amount of carbon dioxide dissolved in lakes.