A vertebrate is an animal with a backbone or spinal column. This group includes mammals, birds, fish, reptiles, and amphibians. The backbone provides support and protection for the spinal cord.
As an octopus does not have a bony internal skeleton, it is an invertebrate.
Linnaeus developed a new naming system as a way to relate to other creatures based on their characteristics/appearance. Their names help us determine a trait or "hint" of the animal as well as provide it's family. For example a dog is domesticus caninus or a tamed dog where as the arctic fox (had a previous name but now its changed) is called vulpes lagopus where the vulpes is used for fox (red fox is called vulpes vulpes) and lagopus meaning "hare" due to the feet of the white fox. The naming system helps us sort animal according to features. This is more complex by adding the group, subgroup, family, genre, down to specie. Each section of the naming system adds a new trait. Ex: Humans Kingdom-Animalia (animal) Phylum-Chordata (true invertabrates and animals with chordata cord) Subphylum-Vertebrata (vertabrat) Class-mammalia (mammal) Subclass-Theria (includes mammals except one, monotremes) Infraclass-Eutheria (true/good) weird but true, meant for animals developed by placentas Order-Primates Suborder-Anthropoidea (man) Subfamily-Hominoidea (resembling hominids) Family-hominidae (hominids) Genus-Homo (same/alike) Species-Sapiens (wisedom)
A seahorse is small and lives in the ocean. A horse is bigger and lives on land. Male seahorses give birth to their baby seahorses. Female horses give birth to their young.