Question

The common origin of man and chimpanzee is best shown by

• A. Dental Formula
• B. Binocular Vision
• C. Chromosome Number
• D. Cranial Capacity

Answer 1

The correct option is C

Chromosome Number

The correct option is option C.

Explanation for the correct option:

Option C:

1. There is a close genetic similarity between humans and chimpanzees.
2. The formation of the human chromosome $2$ provides conclusive evidence that humans evolved from a shared ancestor with chimpanzees and bonobos.
3. Each species has a typical number of chromosomes that vary in size and shape.
4. For example, chimpanzees and other monkeys have $48$ chromosomes, while humans have $46$ chromosomes.
5. When exposed to certain colours, the chromosomes will uniquely stain, creating a band pattern along their length.
6. The unique bending profile of each chromosome helps geneticists identify them under a microscope.
7. When aligned, the human and corresponding chimpanzee chromosomes show near-uniform bending patterns, band locations, band size, and band stain intensity.
8. For evolutionary biologists, this similarity demonstrates powerful evidence of human and chimpanzee co-evolution.
9. Therefore, the common origin of man and chimpanzee is best expressed by chromosome number and not by binocular vision, cranial ability, and dental formula.

Explanation for the incorrect option:

Option A:

1. The dental formula is a way to calculate how many of each kind of tooth there are in each quadrant of the mouth.
2. Dental formulas differ between species and maybe between the mandibular and maxillary dentition.
3. The dental formulae of humans and chimpanzees are the same and are represented by formulae 2.1.2.3.
4. But this can't be strong evidence of the common origin of chimpanzees and humans.

Option B:

1. When we lay our eyes side by side, each one records a slightly different scene.
2. We refer to this as binocular vision.
3. The brain processes and superimposes the signals from the two eyes to create a single, three-dimensional image.
4. All primates including humans and chimpanzees have binocular vision.

Option D:

1. The volume of the inside of the cranium in vertebrates with a cranium and a brain is known as cranial capacity.
2. The cranial volume is used to roughly estimate the brain's size, which is also suggestive of the organism's intellect.
3. The average cranial capacity of humans is 1400 cc and chimpanzees is 400 cc.

Final answer: The common origin of man and chimpanzee is best shown by Chromosome number.