Question

Match the two sets.

Column 1	Column 2
I. Pioneers replacement	A. Vegetation which modifies its own environment and thus causing its own
II. Autogenic succession	B. Replacement of existing community by external conditions
III. Allogenic succession	C. Establishment
IV. Ecesi	D. Primary colonisers

A. I - D, II-A, III - B, IV - C
B. I - A, II - B, III - C, IV - D
C. I - B, II - A, III - D, IV - C
D. I - A, II - D, III - C, IV - B

Answer 1

Hint: Ecological succession is the mechanism that explains how a biological community's composition evolves over time. The ecological succession is classified into a number of types based on factors like origin, cause, community composition and nature of the substratum.

Complete Answer:
- Pioneer species are those species that are colonised in an environment that historically did not have any residents. When it invades the sterile rocks, algae is the perfect example of pioneer succession. In general, autotrophs, or those that sustain harmonious ecological contact with autotrophic bacteria, herbaceous plants, lichens, are pioneer organisms.
- "Auto-" means self or the same, and "-genic" means that it creates or induces. Autogenic succession thus refers to evolutionary succession driven within an ecosystem by biotic forces, which ultimately contributes to environmental changes. The plants themselves, for instance, allow succession to occur, leading to a slow ecological transition in a specific spot of soil known as an inhabiting species progression.
- Allogenic succession applies, by abiotic, nonliving causes, often geological, to ecological succession (change of ecology). Every natural geological catastrophe, including redirection of hydrology or severe climate change, will be an allogenic cause. Huge allogeneic influences in ecological transition will be an ice age or supervolcanic eruption.
- The method of effective establishment of a species in the bare field is called Ecesis. The seeds or spores that, due to migration, have entered the new region will germinate, expand and replicate. Due to the harsh environmental situation existing in the area, only a few progenies can survive.

Hence the correct answer is option A.

Note: In ecological succession, we have five main factors namely primary succession, secondary succession, pioneer and niche organisms, climax and subclimax communities. Allogenic succession is the succession in ecology, guided by the abiotic elements of an ecosystem. Autogenic succession, by comparison, is driven by the ecosystem's biotic elements.