| [Visitor (111.8.*.*)]answers [Chinese ] | Time :2020-03-24 | Autotrophs are at the beginning of the food chain and together form the first trophic level. All animals that feed on producers (mainly green plants) are in the second trophic level, namely the herbivore trophic level. The third nutritional level includes all carnivores that feed on herbivores. And so on, there will be a fourth nutritional level and a fifth nutritional level.
As the energy flows through each trophic level will be greatly reduced, the energy that the next trophic level can receive is only between 10% and 20% of the assimilation amount of the previous trophic level, so the food chain cannot be too long. The trophic level in the ecosystem will not be too long, generally only four or five, and rarely more than six.
Generally speaking, the higher the position of the trophic level, the less the species, number, and energy of the organism belonging to this trophic level. When the species, number, and energy of a trophic level are less than a certain level, it is impossible to maintain another A nutritional presence.
Counting from the producer, the organisms that have obtained food through the same level are called homotrophic organisms, but the relationship of the food chain in the community or ecosystem is complicated. Except for the producer and some food-eating animals that have limited food habits, Most other organisms belong to more than 2 trophic levels, and their trophic levels often change with age and conditions. For example: broad-finned pheasants feed on insects and algae at the same time; sweetfish grow with them From a secondary consumer to a primary consumer: it is animal food at the seeding stage, and changes to plant food and omnivorous food as the individual develops. Larvae have been feeding on ceratops, copepods, and other small crustaceans Back to the river.During the swim into the river, the feeding organs evolved, and the feeding gradually changed to lower algae... |
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