How are invertebrates classified?

Invertebrate, arthropod or insect? This Monarch caterpillar is an invertebrate. It is also an insect and an arthropod. Of all the animal species, it is estimated that well over 90% are invertebrates. Of all invertebrates, the insects are by far the most numerous. read more

How to classify invertebrates With so many little animals to deal with, some barely visible without a magnifying glass, it's very important that we classify invertebrates. One way is to classify them according to their type and their evolutionary relationship to other species. read more

Invertebrates cells fire in response to similar stimuli as mammals, such as tissue trauma, high temperature, or changes in pH. The first invertebrate in which a neuron cell was identified was the medicinal leech, Hirudo medicinalis. Learning and memory using nociceptors in the sea hare, Aplysia has been described. read more

The simple answer: . Fish, reptiles, birds, and mammals are all vertebrates , i.e., having a spinal column.. read more