Question

What does the following sequence represent:Blue green algae ⎯→ Crustose lichens↓shrubs ←⎯ mosses ←⎯ Foliose lichens↓Dicotyledonous trees(a) Ecological succession
(b) Genetic drift
(c) Phylogenetic trend
(d) A food pyramid

Answer 1

The following sequence represents (a) Ecological succession.

Explanation:

• Ecological succession defines change in the structure of species over time.
• It depends on the impact of environment on organisms.  
• This change creates complexity among the species and become stable after sometime. The stabilised environment is called climax community (forest land).
• The succession begins in the land that had underwent severe damage like forest fire, lava flow, landslide and so on. This change takes place after mass extinction.