Population growth analysis: The transitional middle portion of a logistic population growth curve represents which type of growth behaviour?
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AGeometric growth
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BLogarithmic growth
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CFirst over curve
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DA constant rate
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ENone of these
Answer
Correct Answer: Geometric growth
Explanation
Introduction / Context:The logistic growth curve is widely used in biology and demography. It has three phases: lag phase, exponential (geometric) phase, and stationary phase. This question tests the recognition of the middle phase.
Given Data / Assumptions:
- Curve type: Logistic (S-shaped).
- Middle portion: Represents rapid growth before resource limitations act.
Concept / Approach:The middle part of a logistic curve shows exponential (geometric) growth, as resources are abundant and population grows rapidly. Later, growth slows down due to limiting factors.
Step-by-Step Solution:
1. Initial stage → lag (slow growth).2. Middle stage → geometric (exponential) growth due to abundance of resources.3. Final stage → constant/stabilized growth.Verification / Alternative check:Population models in civil engineering planning confirm that exponential growth precedes saturation in urban populations.
Why Other Options Are Wrong:
- Logarithmic growth: Refers to slower, diminishing growth, not the rapid stage.
- First over curve: Not a standard term in growth modelling.
- A constant rate: Refers to arithmetic growth, not logistic mid-phase.
Common Pitfalls:
- Confusing logarithmic with geometric growth due to similar wording.
- Believing population always grows linearly, ignoring saturation effects.
Final Answer:Geometric growth