Unit: Ecology How does succession lead to changes in communities Unit: Ecology How does succession lead to changes in communities? Ecological Succession –the natural replacement of one community with another until a climax stage is reached.

Types of succession: 1. Primary Succession Life starts from scratch Ex. Volcanic eruptions and drop in sea levels cause new land to form Always starts with rock (new or old)

2. Secondary succession Life starts over again Ecosystem already exists and is disturbed Starts with soil there already Ex. Fire, natural disaster or human action Migration - populations move in or out of an area human actions destroy an existing habitat

Order of Succession A community starts with the pioneer species-the first species that lives in the area. Examples: Bacteria and Lichen(fungus and bacteria or algae) and mosses

Order of Succession 2. Next come the grasses, small plants. The animals that would inhabit(live in) the area would be insects, small rodents

Order of Succession 3. Next come the small shrubs. The animals that would inhabit the area would be small animals, rodents, rabbits, snakes, fox

Order of Succession 4. Next come the small trees(pines, spruces). The animals that would inhabit the area would be deer, coyote, wolves

Order of succession 5. Last come the large trees(maple, oak). The animals that would inhabit the area would be all animals, lions, tigers and bears, OH MY!!

Process of succession: How does succession happen? The above organisms live, some will die, and decomposers will break them down to return nutrients to the soil, which makes the soil richer. This changes the environment to a better environment for different species life. When succession slows down, a diverse, stable and mature community develops. This is called the climax community.