Why do living things need food 2

Navigation aid:

  • Start the "Lake" food cycle

  • The program "Von Stachelinski und Steinmännchen" in the knowledge pool

  • How animation works

    The operation of the interactive animation is intuitive: Simply click on the desired animal and you can experience part of the "lake" food chain in an original way.

    The main natural predators of plankton are tadpoles.

    Food chains in the lake

    In a material cycle, we differentiate between three large groups: producers (manufacturers), consumers (consumers) and destructors (decomposers).

    Producers are plants and Seaweedthat form organic substances (e.g. sugar) from non-organic substances such as carbon dioxide. These creatures do not need much for this - they are autotrophic, which means that they produce their own food. Using photosynthesis, they can produce sugar from carbon dioxide, sunlight and water. In order to create proteins that allow growth and reproduction, plants and algae also need some nutrients that they cannot produce themselves: above all phosphorus and nitrogen. We humans also need these substances, but have the advantage that we only have to eat a piece of bread, for example: the wheat plant has done our work for us and phosphorus and nitrogen are already stored in their tissues. Plants, however, are dependent on finding phosphorus and nitrogen in the water or in the soil and taking them up through their roots.

    Tadpoles are particularly threatened by the insect larvae of the yellow fire beetle.

    Consumers cannot produce organic substances themselves and therefore have to take in this food. You are heterotrophic. They either eat the producers directly (and are therefore herbivores) or they eat other animals. In the lake ecosystem, consumers are divided into three groups:

    Consumers I feed on phytoplankton or other autotrophic creatures. Consumers I include zooplankton, but also some fish species, such as the roach. Muskrats and beavers are also consumers I, as they only feed on plants.

    Consumers II feed on herbivores (i.e. consumers I). Many fry, even if they become fish predators as adults, eat zooplankton. Other consumers II feed on small animals such as worms and insect larvae that live on plants and in the soil. These include fish such as Moderlieschen and Bearded Gobies, but also amphibians such as the pond newt.

    As a predatory fish, the pike plays a dominant role in the "lake" food chain. He is counted among the third-order consumers.

    Consumers III are the top predators. They eat other carnivores. They include, for example, pike, otters and gray herons, which feed on fish and amphibians.

    To the Destructors For example, there are many worms, insects and crabs that eat dead plant and animal material. Further stages in the decomposition process are then taken over by protozoa, bacteria and fungi. They feed on what the larger decomposers leave and on the excretions of the animals. The bacteria in turn excrete phosphorus and nitrogen as waste products. In this way, these basic building blocks get back into the cycle and are available again to the producers.