According the Darwinian theory, the rate of appearance of new forms is linked to their life cycles. Explain.

Explanation

**Step-by-Step Solution:**

1. **Introduction to Darwinian Theory**: The Darwinian theory of evolution is primarily based on two key concepts: branching descent and natural selection. These concepts explain how species evolve over time through a process of gradual change.

2. **Linking Life Cycle to Evolution**: According to Darwin, the rate at which new forms of organisms appear is closely linked to their life cycles. Organisms with shorter life cycles tend to evolve more rapidly than those with longer life cycles.

3. **Example of Microbes**: In a laboratory setting, microbes can reproduce very quickly, often dividing every hour or even every 90 minutes. This rapid division allows for a swift generation of new colonies. For instance, if a single microbe is cultured, it can produce a whole colony in a short period, leading to faster evolutionary changes.

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