Ecological succession describes the pattern of changes in communities over time.

Question

Ecological succession describes the pattern of changes in communities over time. The graph below shows changes in plant diversity following the abandonment of an agricultural field in a temperate biome. (a) Discuss the differences in plant diversity shown in the graph and explain how the changes affect the animal species composition between years 0 and 120. (b) Identify TWO biotic and TWO abiotic factors and discuss how each could influence the pattern of ecological succession. (c) Design a controlled experiment to determine how the diversity of plant species in a newly abandoned field would be affected by large herbivores.

Explanation / Answer

(a)Discussion of differences in diversity shown in the graph

• Differences in the amount of diversity

1)More diversity in ground flora and shrubs .

2)Less diversity in understory and canopy .

• Differences in the rate of change in diversity

1) Rapid change in ground flora and shrubs.

2)Slow change in understory and canopy .

• Differences in the rate to community stabilization

1)Faster for ground flora .

2) Slower for understory and canopy.

Explanation of effect on animal species composition

• Pioneer community consists of small herbivores, insects, and other small, ground-dwelling animals.

• Climax community consists of insects, birds, and mammals and is multilayered.

b)Examples of biotic factor:

• Competition

• Predation

• Herbivory

Disease

Parasitism

• Seed dispersal

• Nitrogen fixation

• Reproductive strategy

• Human impact

Examples of abiotic factors

Climate

• Rainfall

• Light

• Wind

• Temperature

• Soil composition

• Fire

• Drought

• Altitude

• Geographic location

c)Experiment design

• Identify the independent variable and how it is manipulated

. • Identify the dependent variable and how it is measured (e.g., “count number of species”; not “observe diversity”). • Discuss variables to be held constant (at least three; one can be “divide the field in half”).

• Identify the control (e.g., no herbivores).

• Verification and replication (e.g., large plot or many plots).

• Hypothesis or testable prediction related to species diversity

Related Questions

Navigate

• Browse (All)
• Browse E
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.