AP BIOLOGY

Detailed explanation-1: -The food chain of a pond can include algae (producer), small animals, insects, and their larvae, small fish, big fish, and a fish-eating bird. Algae ⇢ insects ⇢ fish ⇢ hawk. Phytoplankton ⇢ zooplankton ⇢ small fish ⇢ large fish ⇢ whale, are some of the examples of the aquatic food chain.

Detailed explanation-2: -These levels are divided into producers (first trophic level) and consumers (second, third and fourth trophic levels). There are different types of consumers. There are herbivores (primary consumers) that eat the plants or carnivores (secondary and tertiary consumers) that eat the herbivores.

Detailed explanation-3: -Producers i.e. grasses(1st trophic level) are eaten by grasshoppers(2nd trophic level) which are then eaten by frogs (3rd trophic level). The Frogs are then eaten by snakes(4th trophic level). Vultures or eagles(5th trophic level) then prey on these snakes.

Detailed explanation-4: -In the case of marine ecosystems, the trophic level of most fish and other marine consumers takes value between 2.0 and 5.0. The upper value, 5.0, is unusual, even for large fish, though it occurs in apex predators of marine mammals, such as polar bears and killer whales.