River food web
The fox eats the rat, the auklet, and the gull because the fox is a secondary consumer. The rat gets eaten by the kittiwake or the gull because it's a primary consumer. The gull eats the auklet. The gull is a primary consumer. The auklet eats the zooplankton. Salmon eats Kirkland zooplankton but gets eaten by the gull of the cephalopod. The zooplankton gets eaten by the phytoplankton& the sand lance but eats the krill. Phytoplankton gets eaten by the sand lance. The sand lance gets eaten by the puffin, kittiwake, and cephalopod. The cephalopod eats salmon, sand lance & krill.
Fungus and algae have a mutualistic relationship in which they are combined to form lichen. The algae produces food for itself and the fungus whereas the fungus takes in water for itself and the algae. Both are benefited.
The giant river turtle which lives in the amazon basin, and other places, has green algae on its shell. The giant river turtle is not affected by the green algae, while without the turtle the algae would not have a habitat to thrive in.
The Candiru is a small parasitic catfish found in the Amazon. The fish can grow to a maximum length of around six inches. Candiru feed on the blood of their host creatures by swimming into the gills and using razor sharp spines on its head to attach itself. It then chews its way through the host until it reaches a major artery and drinks blood until it is satiated.
People affecting the ecosystem
Humans rely on natural ecosystems to provide many ‘ecosystem services’- such as pollination of crops, and cleaning air and water. Humans also rely on ecosystems to provide them with fertile soil, mineral nutrients, fish and game.
However, human activities often affect ecosystems in negative ways because human systems are not closed loop systems.
Human waste enters other natural ecosystems, where it can cause them to become unbalanced. Sometimes this waste can build up to harmful levels. Examples of human waste that can affect ecosystems are:
gases produced when fossil fuels are burned
Humans sometimes harvest plants and animals from natural ecosystems and this can also unbalance them.