Hepatoc portal system has evolved in protochordates

Options

A. Hemichordates
B. Urochordates
C. Cephalochordates
D. All the above

Answer

**Step-by-Step Solution:**

1. **Understanding the Hepatic Portal System**: The hepatic portal system is a network of veins that carries blood from the digestive organs to the liver. This system allows for the processing of nutrients and detoxification before the blood enters the general circulation.

2. **Identifying Protochordates**: Protochordates include three main groups: hemichordates, urochordates, and cephalocordates. Understanding the characteristics of each group is essential to determine which, if any, possess a hepatic portal system.

3. **Analyzing Hemichordates**: Hemichordates are a group of protochordates that have an open circulatory system. In an open circulatory system, blood is not contained within vessels, which means they do not have a hepatic portal system. Therefore, hemichordates do not possess this system.

4. **Examining Urochordates**: Urochordates, also known as tunicates, have a well-developed closed circulatory system, meaning their blood is contained within vessels. However, despite this, they lack a hepatic portal system. Thus, this group also does not have a hepatic portal system.

5. **Evaluating Cephalocordates**: Cephalocordates, such as lancelets, possess a well-developed circulatory system and do have a hepatic portal system. This indicates that they can transport blood from the digestive system to the liver effectively.

6. **Conclusion**: Based on the analysis of each group of protochordates, the only group that has evolved a hepatic portal system is the cephalocordates. Therefore, the correct answer to the question is "cephalocordates."

**Final Answer**: Cephalocordates

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