The entire sequence of communities that successively replace one another in a particular area is called a:

Ecological succession is the gradual and fairly predictable process by which the species in a community change over time, until a stable community is formed. The whole sequence of communities that develop one after another in a given area during succession is called a sere. Each temporary community in the sequence is called a seral stage or seral community.

The first organisms to colonise a bare area are called pioneer species. On bare rocks, lichens are usually the pioneers. They secrete acids that break down rock and help form a thin layer of soil. Mosses follow, then grasses, then shrubs, and finally trees. The final, stable and self-perpetuating community that is in balance with the climate of the area is called the climax community, such as a forest.

Types of succession:

Primary succession begins in an area where no living organisms or soil existed before, such as bare rock, newly cooled lava or a new sand dune. It is very slow and can take hundreds or thousands of years.

Secondary succession begins in an area where a community existed earlier but was destroyed, such as abandoned farmland, a burned forest or a cleared area. Since soil is already present, it is faster.

Seres are named according to the habitat in which succession begins:

• Hydrosere: succession in water, such as a pond or lake.
• Xerosere: succession in a dry area; a lithosere begins on bare rock, and a psammosere on sand.
• Halosere: succession in salty water or soil.
• Ecological succession was studied by scientists such as Frederic Clements, who described the climax concept.

Why not the other options?

• ✗The climax is the final stable community, not the whole sequence.
• ✗An ecotone is a transition zone between two communities.
• ✗A biome is a large regional ecosystem.