You've found an unfamiliar animal. How would you determine if it was a vertebrate or not without dissecting it?

When finding an unfamiliar animal, to know if it is a vertebrate or not, we need to observe its size, bone, skin and skull arrangement, but to understand more, we need to know that

The main characteristic among vertebrate animals is the presence of spinal cord and vertebral column, which is formed by several vertebrae. Vertebrates have muscles and a skeleton, allowing them to perform more difficult movements than invertebrate animals.

Many vertebrate animals have a developed nervous system, with the central system built up by the brain and spinal cord. The so-called lower vertebrates are largely controlled by the brain. The brain plays the role of directing the functions of sensory organs.

All vertebrates have a head and skull surrounding the brain. In the embryonic stage they have a neural crest, which creates structures such as cephalic ones. The respiration of vertebrate animals is carried out through gills, lungs or even through the skin.

With this information, we came to the conclusion that in order to know if the animal is a vertebrate, we need to visualize if it is rigid, if it has bones, more elaborate movements, muscles and skull.

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If an animal is having a well developed skeleton system, a backbone then it belongs to vertebrate. Also, size is an important factor to identify vertebrate and invertebrate.

Explanation:

Vertebrates have a well developed skeleton system and backbone. Their skeleton system is made up of bones and cartilage. While, invertebrates don't have any backbone.

Due to lack of backbone or skeleton system, invertebrates are small in size. As there is no proper mechanism to support large body so invertebrates are small in size and also they move very slowly. This is also a major difference in vertebrate and invertebrate.

Another important difference between vertebrate and invertebrate is that body of vertebrate is covered with some structure like hair, feathers, skin, scales or a combination of these.

These features help to distinguish vertebrate from invertebrate by observing them, no need to dissect.