Question

type your response in the box.
what were the three models of succession? explain each of them. which model do you think would be more accurate? why do you think that?

Explanation:

The three models of ecological succession are:

1. Facilitation Model: Pioneer species modify the environment (e.g., fix nitrogen, create soil) to make it more suitable for later species. Later species depend on these changes. For example, lichens breaking down rock to form soil for plants.
2. Inhibition Model: Early - colonizing species inhibit the growth of later - arriving species through competition (for resources like light, nutrients) or allelopathy (releasing chemicals that harm others). The first - come species tend to dominate until disturbed (e.g., a dominant tree species shading out smaller plants).
3. Tolerance Model: Species' success depends on their ability to tolerate environmental conditions and resource levels. Later - successional species are more tolerant of low - resource conditions (e.g., shade - tolerant plants in a forest understory) and can co - exist with earlier species as resources change.

Regarding accuracy, the Tolerance Model is often considered more accurate. Most natural ecosystems show a mix of facilitation, inhibition, and tolerance. The Tolerance Model accounts for the fact that species can co - exist and succession is not always a unidirectional, species - replacement process. It also better explains the presence of early - successional species even in later - successional stages (e.g., some weedy species can still be found in a mature forest if there are disturbances like a tree fall creating a gap with light). The Facilitation Model is too linear, assuming a strict replacement, and the Inhibition Model overemphasizes competition without accounting for the ability of species to adapt to changing conditions.

Answer:

The three models of succession are: 1. Facilitation Model (pioneer species modify the environment for later species); 2. Inhibition Model (early species inhibit later species); 3. Tolerance Model (species' success depends on resource tolerance). The Tolerance Model is more accurate as it accounts for species co - existence and the mixed processes (facilitation, inhibition, and tolerance) in natural ecosystems, unlike the more linear Facilitation Model or the over - competitive Inhibition Model.