DENDROLOGY

Detailed explanation-1: -invertebrate, any animal that lacks a vertebral column, or backbone, in contrast to the cartilaginous or bony vertebrates. More than 90 percent of all living animal species are invertebrates.

Detailed explanation-2: -Invertebrates are animals without a backbone or bony skeleton. They range in size from microscopic mites and almost invisible flies to giant squid with soccer-ball-size eyes. This is by far the largest group in the animal kingdom: 97 percent of all animals are invertebrates.

Detailed explanation-3: -Invertebrates are those organisms that lack a spine or back bone. They evolved before vertebrates and are generally a simpler form of life having a simple notochord or simple nervous system. The support and structure that comes from the backbone come from other structures in invertebrates.

Detailed explanation-4: -As invertebrates lack an internal skeletal structure, they sometimes have an external skeleton that protects their soft bodies called an “exoskeleton.” In general, invertebrate success often comes from their ability to reproduce extremely quickly, unlike many vertebrates who take years to become fully grown.