AP BIOLOGY

Detailed explanation-1: -Phytoplankton, tiny organisms that live in the ocean, are autotrophs. Some types of bacteria are autotrophs. Most autotrophs use a process called photosynthesis to make their food.

Detailed explanation-2: -Phytoplankton. Phytoplankton is made of very tiny–usually one-celled–plants. Since plants make their own food and release oxygen as a byproduct, all the other living things in the ocean depend on them directly or indirectly for food or oxygen.

Detailed explanation-3: -The term phytoplankton encompasses all photoautotrophic microorganisms in aquatic food webs. However, unlike terrestrial communities, where most autotrophs are plants, phytoplankton are a diverse group, incorporating protistan eukaryotes and both eubacterial and archaebacterial prokaryotes.

Detailed explanation-4: -Derived from the Greek words phyto (plant) and plankton (made to wander or drift), phytoplankton are microscopic organisms that live in watery environments, both salty and fresh.

Detailed explanation-5: -Zooplankton are heterotrophic (other-feeding), whereas phytoplankton are autotrophic (self-feeding). In other words, zooplankton cannot manufacture their own food. Rather, they must eat other plants or animals instead. In particular, they eat phytoplankton, which are generally smaller than zooplankton.