Final answer:
Zooplankton are small free-floating animals that form part of plankton, characterized by their inability to swim against currents and their role in aquatic food webs as they feed on phytoplankton and serve as prey for larger animals.
Step-by-step explanation:
Definition of Zooplankton
Small free-floating animals that form part of plankton are commonly referred to as zooplankton. These are tiny and microscopic organisms that drift or float in aquatic environments like the sea or freshwater bodies. Zooplankton chiefly consists of a variety of organisms such as diatoms, protozoans, small crustaceans, as well as the eggs and larval stages of larger animals. They play a crucial role in aquatic food webs, serving as a significant source of food for larger aquatic animals.
Zooplankton are distinguished from other types of plankton such as phytoplankton, which are bacteria and algae that use photosynthesis to produce their food from sunlight. On the other hand, zooplankton typically feed on phytoplankton and other smaller organisms. They are a critical component of the planktonic community, which is characterized by organisms that cannot swim against prevailing currents, tides, and waves.