Consider the following kinds of organisms: 1. Copepods 2. Cyanobacteria 3. Diatoms 4. Foraminifera Which of the above are primary producers in the food cha

1. A. 1 and 2
2. B. 2 and 3
3. C. 3 and 4
4. D. 1 and 4

Answer: B

Explanation

Autotrophs or primary producers are organisms that acquire their energy from sunlight and materials from nonliving sources. Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Copepods are major secondary producers in the World Ocean. They represent an important link between phytoplankton, microzooplankton and higher trophic levels such as fish. They are an important source of food for many fish species but also a significant producer of detritus. Hence, option 1 is not correct. Cyanobacteria, also called blue-green algae, are microscopic organisms found naturally in all types of water. Cyanobacteria are important primary producers and form a part of the phytoplankton. They may also form biofilms and mats (benthic cyanobacteria). Hence option 2 is correct. Diatoms are photosynthesising algae, they have a siliceous skeleton (frustule) and are found in almost every aquatic environment including fresh and marine waters. Diatoms are one of the major primary producers in the ocean, responsible annually for ~20% of photosynthetically fixed CO2 on Earth. Hence option 3 is correct. Foraminifera are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses. Hence, option 4 is not correct.