The following are associated with succession EXCEPT

Analyze the question: Ecological succession is the gradual, orderly change in the community of organisms in an area over time, from a pioneer community to a climax community. We need the option that is NOT associated with it.

Concept: During succession:

• Species composition changes. Pioneers (lichens, mosses) are replaced by grasses, shrubs, and then trees. This makes A associated with succession.
• Competition occurs. Later species out-compete earlier ones for light, water, and nutrients. This makes B associated.
• Habitat changes. Organisms modify the environment, for example by forming soil and giving shade, so conditions change. This makes E associated.
• Diversity of organisms increases. More species establish as succession proceeds, until the climax community is reached. This makes D associated.
• Number of organisms. In general, succession involves an increase in the number and biomass of organisms, as the community develops from bare rock to forest. A decrease in number of organisms is not a characteristic feature of succession.

Step-by-step elimination:

1. A: species composition changes, so it is associated.
2. B: competition drives the replacement of species, so it is associated.
3. C: a decrease in number of organisms is the opposite of the usual trend, so it is not associated.
4. D: diversity increases, so it is associated.
5. E: habitat modification is central to succession, so it is associated.

Answer: C. decrease in number of organisms

Exam tip: Remember succession as "more, bigger, more diverse": more species, more biomass, more complex habitat. When a question says "EXCEPT", look for the option that describes the opposite trend, such as a decrease.