Which of the following are analogous structures?

Options

A. (1) Forelimbs of mammals
B. (2) Thorn of Bougainvillea and tendril of cucurbita
C. (3) Kidneys of man and malpighian tubules of cockroach
D. (4) All of the above

Answer

To determine which of the following are analogous structures, we need to understand the definitions of homologous and analogous structures:

1. **Understand Homologous Structures**:
- Homologous structures are those that have a common evolutionary origin but have diverged to perform different functions. For example, the forelimbs of mammals (like humans, whales, and bats) have the same basic skeletal structure but serve different purposes (grasping, swimming, flying).

2. **Understand Analogous Structures**:
- Analogous structures, on the other hand, are those that do not share a common ancestor but have evolved to perform similar functions. An example of this would be the wings of birds and insects; they serve the same function (flight) but have different evolutionary origins.

3. **Analyze the Given Options**:
- We need to evaluate the options provided in the question to identify which ones are analogous:
- **Option 1**: Four limbs of mammals – These are homologous structures as they share a common ancestor.
- **Option 2**: Thorns of Bougainvillea and tendrils of Cucurbita – These are also homologous as they arise from the same part of the plant (axillary buds).
- **Option 3**: Kidneys of man and Malpighian tubules of cockroaches – These are analogous structures. They perform the same function (excretion) but have different evolutionary origins and structures.
- **Option 4**: (Not provided in the transcript, but if it were another example, we would analyze it similarly).

4. **Conclusion**:
- Based on the analysis, the correct answer to the question is **Option 3**: Kidneys of man and Malpighian tubules of cockroaches are analogous structures.