Name: Ecological Pyramids
Uploaded: 2019-07-19
Duration: 7 min 39 s
Description: An ecological pyramid is a graphical representation showing the relationship between different organisms in an ecosystem. Learn more in this video.

Question

What is ecological succession? Describe primary and secondary succession.

Accepted Answer

Ecological succession means the gradual change in species composition in a given area. It is a gradual process where one species can be replaced by others, which leads to change in the physical environment. Succession are divided based on the nature of the habitat into hydrarch, mesarch and xerarch. Hydrarch succession takes place in wet areas like pond, wetland, etc., while xerarch succession takes place in dry areas such as a rock.

Succession is classified into two types: primary and secondary succession.

Primary succession: In this type, the organism starts invading an area, which was unused, such as a newly formed pond, bare rocks, etc. The first species to invade and establish in a new area is called pioneer species. In a bare rock, the pioneer species are lichens that are able to secrete acids that help to disintegrate rock leads to weathering and soil formation. This is following by small plants like bryophytes, which are able to take hold in the small amount of soil. This is succeeded by higher plants, and after several more stages, ultimately leads to a stable climax forest community. It remains stable as long as the environment remains unchanged. Hence, the xerophytic habitat converted into a mesophytic one. In primary succession in water, the pioneer species are the small phytoplanktons which are replaced with time by rooted-submerged plants.

Secondary succession: It starts in an area where life once existed, for example, an abandoned crop field, land affected by floods, burnt forests, etc. The species that invade depend on the condition of the soil, availability of water, the environment, etc. The rate of succession is much faster because the soil is already there, and hence, climax is also reached more quickly.

What is ecological succession? Describe primary and secondary succession.

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