Do you have any idea about how many animal species are present on Earth? There’re as many as 30 million animal species alive. It always excites a person to understand more about these species, but it is pretty a challenging task too. As there is enormous number of species, it becomes challenging to remember each one of them. So, to possess a clearer idea, you can segregate these species of animals into 6 fundamental groups.
Invertebrates are the 1st animal species group. The name of the category itself suggests that invertebrates don’t have a vertebral column or a spine. Most of the back pain sufferers may as well wish that they were born without a spine too. Flatworms, microorganisms, insects and so on are some of the species, which come under this class.
Another well known animal group is formed by fishes. Fishes are the first vertebrates that have evolved. These species can be additionally classified into three divisions that are cartilaginous fishes, lobe finned fishes as well as ray finned fishes. Ray finned fish is one of the most versatile kinds of fish that has 24,000 species. Fishes make a brilliant choice for pet, other than a pet dog.
Another broad category of animal is amphibians. These are the animals that live both- on land and water. The first amphibians developed from lobe finned fishes, approximately 370 million years ago. Approximately, there are 5000 to 7000 species of amphibians. Some animals that fall in this category include frogs, salamanders and the like.
One of the most significant categories of species of animals is Reptiles. These cold blooded vertebrates exhibit two varying traits. One of their traits is that they have scales all over their body and the other is that they produce hard eggs. First amphibian came into existence 340 million years ago. Some of the popular amphibians are crocodiles, tuataras, squamates, turtles, etc.
Mammals is perhaps the most developed category of animals. They inhibit a diverse range of characteristics and can adapt themselves to a large range of habitats. There are at least 5,400 species of animals alive today. Mammals are extremely diverse. They range from the tiny Bumblebee Bat, that is three centimeters to the blue whale, which is 33 cm long. Did you know that human beings are also mammals?
When we chat about animals, we also speak about birds. There are many birds that are animals and that can even fly. Moreover, birds have distinct features that make them different from the others. These features are furcula, feathers, bills, etc. Flying birds give a sense of happiness. So, bird watching is a hobby for many individuals. You can also enjoy bird watching, with no worries regarding sun tan.
Knowing more about various categories of animas is enriching really.