Plankton (singular plankter) are a diverse group of organisms that live in the water column of large bodies of water and that cannot swim against a current. They provide a crucial source of food to many large aquatic organisms, such as fish and whales.lankton are primarily divided into broad functional (or trophic level) groups: 1  Phytoplankton (from Greek phyton, or plant), autotrophic, prokaryotic or eukaryotic algae that live near the water surface where there is sufficient light to support photosynthesis.
Tree swallows breed between May and September. They raise one brood per year. Tree swallows usually nest solitarily. However, they may nest near other tree swallows if nest cavities are close together. Tree swallows build their nests in late April or early May. Their nests are usually built in holes in dead or live trees or in hollow stumps. The female builds the nest using grasses, mosses, rootlets, and aquatic plants.
Symbiotic relationships in nature are ones in which two organisms benefit each other's survival. There are many examples that can be given, but one of the most interesting is the Rufous woodpecker of India and Sri Lanka (formerly Ceylon) and the black tree ant.The main diet of the Rufous woodpecker is black tree ants.One of the main items in the diet of the black tree ants is bird eggs. In the spring of the year when the woodpeckers get ready to lay their eggs, they will find a nest of the black tree ant and put their nest in the ant's nest.he main diet of the Rufous woodpecker is black tree ants. One of the main items in the diet of the black tree ants is bird eggs. In the spring of the year when the woodpeckers get ready to lay their eggs, they will find a nest of the black tree ant and put their nest in the ant's nest.