Medical definition of posterior median sulcus: a shallow groove along the midline of the posterior part of the spinal cord that separates the twoâ¦ a shallow groove along the midline of the posterior part of the spinal cord that separates the two posterior funiculi and is the externalâ¦
Zooplankton Fact Sheet. Zooplankton are microscopic invertebrate animals that swim or drift in water. They are at the base of the food chain, feeding on microscopic plants and being fed upon by aquatic insects, fish and salamanders.ooplankton Fact Sheet. Zooplankton are microscopic invertebrate animals that swim or drift in water. They are at the base of the food chain, feeding on microscopic plants and being fed upon by aquatic insects, fish and salamanders.
1 The most obvious difference between them is that zooplankton is an animal while phytoplankton is actually a plant. 2  Diatoms and algae are two forms of phytoplankton that are commonly seen. 3  Tiny fish or crustaceans like krill are examples of zooplankton.4  Difference in food habits.hough they are similar in size and ecological importance, there is a world of difference between them. 1  Basic difference. 2  The most obvious difference between them is that zooplankton is an animal while phytoplankton is actually a plant. 3  Diatoms and algae are two forms of phytoplankton that are commonly seen.