Following the retreat of a glacier, a bare expanse of rocky till is exposed to environmental weathering. Place the following ecological succession stages in their correct chronological sequence, from initial colonizers to the establishment of a climax community.
- 1Crustose lichens and mosses colonize the bare rock, accelerating weathering and forming a thin layer of soil.
- 2Herbaceous perennials and shallow-rooted grasses establish in the newly accumulated primitive soil.
- 3Low woody shrubs invade the area, outcompeting herbaceous plants for light and space.
- 4Fast-growing, light-demanding pioneer trees form an early open canopy.
- 5Shade-tolerant hardwood trees replace pioneer species to form a stable climax woodland.
Answer
The correct sequence begins with crustose lichens and mosses, followed by herbaceous perennials and grasses, low woody shrubs, fast-growing pioneer trees, and culminates in a shade-tolerant climax woodland.
Primary succession begins on uncolonized, soil-free substrate with pioneer organisms such as crustose lichens and mosses. As these pioneers weather the rock and accumulate organic debris, soil builds up to support herbaceous perennials and grasses, followed sequentially by shrubs, pioneer trees, and eventually a shade-tolerant climax woodland.
Step-by-Step Solution
Key Concept
Primary ecological succession progresses predictably from pioneer organisms on bare substrate through intermediate seral communities to a stable, self-perpetuating climax community.
Estimated Time:1m 30s