Which of the following is not a character of chordates?

Options

A. Notochord present
B. A post-anal metamerically segmented tail
C. Pharynx perforated by gill slits
D. Heart is dorsal in position

Answer

To determine which of the following is not a character of chordates, we need to review the key characteristics that define the phylum Chordata. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Key Characteristics of Chordates
Chordates are defined by several key features that are present at some stage of their development. These include:
1. **Notochord**: A flexible rod-like structure that provides support.
2. **Pharyngeal Slits or Pouches**: Openings in the throat region that may develop into gills or other structures.
3. **Post-anal Tail**: An extension of the body beyond the anal opening.
4. **Ventral Heart**: The heart is located on the ventral (front) side of the body.

### Step 2: Analyze the Options
Now, let's evaluate the options provided in the question:
1. **Notochord is present**: This is a characteristic of chordates.
2. **Post-anal metamerically segmented tail**: This is also a characteristic of chordates.
3. **Pharynx perforated by gill slits**: This is another characteristic of chordates.
4. **Heart is dorsal in position**: This is incorrect because the heart in chordates is located ventrally (on the front side).

### Step 3: Conclusion
Based on the analysis, the statement that the heart is dorsal in position is not a character of chordates. Therefore, the correct answer is the fourth option.

### Final Answer
The characteristic that is not associated with chordates is: **Heart is dorsal in position.**

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