Question

check your understanding

1. after an extensive forest fire, an affected region of the forest shows signs of ecological succession. place the steps of succession in the correct order.

___ a. the community of diverse organisms approaches a relatively steady state, and a climax community is established.
___ b. larger herbivores and carnivores become more prevalent as taller trees enter the region. these taller trees shade out some of the shorter plants.
___ c. diversity of plant life begins as short grasses enter the region. insects and other small animals begin to diversify in the region.
___ d. shrubs and small conifer trees start to grow in the region.
___ e. fireweed seeds sprouts in the existing soil. with no competition with other plants, these plants grow quickly and produce many seeds.

1. which of the following are factors in determining the stability of a community? select all correct answers.

□ a. the process by which it recovers after a disturbance
□ b. the ability to function during a disturbance
□ c. whether a disturbance is natural or human - made
□ d. the rate of recovery after a disturbance
□ e. multiple populations of predators

1. which of these are pioneer species for primary succession? select all correct answers.

□ a. moss
□ b. grass
□ c. shrubs
□ d. lichen

Explanation:

1.

Ecological succession after a forest fire (secondary succession here as soil is present). Pioneer species (like fireweed in e) come first. Then short grasses (c), then shrubs and small conifers (d), then taller trees (b) which shade out shorter plants, and finally climax community (a).

Community stability is related to its ability to function during a disturbance (b), the process of recovery (a), and the rate of recovery (d). Whether a disturbance is natural or human - made (c) is about the type of disturbance, not directly about community stability. Multiple populations of predators (e) is more about population dynamics within a community, not the overall stability factors.

Pioneer species for primary succession (where there is no soil initially) are lichen (d) which can break down rock to start soil formation and moss (a) which can grow on bare rock or minimal soil. Grass (b) and shrubs (c) usually come after pioneer species.

Answer:

e, c, d, b, a

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