Population termed r-strategists

Options

A. Have J-shaped growth curves
B. Have type III survivorship curves
C. Are usually pioneer species
D. All of these

Explanation

### Step-by-Step Solution:

1. **Definition of R-Strategists**:
- R-strategists are organisms that reproduce quickly and in large numbers. They typically have a high reproductive rate and are often small in size.

2. **Characteristics of R-Strategists**:
- R-strategists tend to have short life spans.
- They produce many offspring at once, but provide little to no parental care.
- They thrive in unstable or unpredictable environments where the ability to reproduce quickly can be advantageous.

3. **Growth Curve**:
- The growth curve of R-strategists is typically represented as a J-shaped curve, which indicates exponential growth.
- In this curve, the population size increases rapidly when resources are abundant and there is little competition.

4. **Type III Survival Curve**:
- R-strategists usually exhibit a Type III survival curve, which means that a large number of offspring are produced, but many do not survive to adulthood.
- This curve reflects high mortality rates in early life stages, with few individuals surviving to reproduce.

5. **Examples of R-Strategists**:
- Common examples of R-strategists include bacteria, insects, and certain plants that can quickly colonize an area after a disturbance.

6. **Pioneer Species**:
- R-strategists are often pioneer species in ecological succession, as they are the first to colonize barren or disturbed environments, paving the way for more stable communities.

### Final Answer:
R-strategists are populations characterized by small-sized organisms that reproduce rapidly and in large numbers, typically exhibiting a J-shaped growth curve and a Type III survival curve. Examples include bacteria and certain insects.

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