Do you’ve any idea about how many animal species are there on Earth? There’re as many as 30 million animal species alive. It always excites a person to know more about these species, but it’s pretty a challenging task too. As there’s enormous number of species, it becomes challenging to bear in mind each one of them. So, to have a clearer idea, you could segregate these species of animals into 6 standard classes.
Invertebrates are the 1st animal species category. The name of the category itself suggests that invertebrates don’t have a vertebral column or a spine. Most of the back pain sufferers might as well wish that they were born without a spine too. Flatworms, microorganisms, insects and so on are some of the species, which fall under this class.
Fishes is another animal group. They were the first vertebrates to evolve. Fishes could be broadly classified into cartilaginous fish, ray finned fish and lobe finned fish. Amongst the three, it is ray finned fish that’s the most versatile and has 24,000 species. If you want an additional pet along with your pet dog, then fishes are a brilliant choice.
Another class is one of the amphibians that live both- in the water and on the land. Almost 370 million years ago, first amphibian species developed from lobe finned fishes. Frogs, salamanders and plenty of more fall in this category. Besides this, 5,000-7,000 amphibians were alive.
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.
Now the other and the most developed category of animals is Mammals. These species exhibit a varied array of features like they are quite adaptable and they can acclimatize to an array of habitats. 5,400 mammals are alive today. Moreover, this category of species is fairly diversified. Small Bumblebee Bat that is three centimeters is a mammal; on the other hand, 33m long blue whale is also a mammal. Are you aware of the fact that human beings too are mammals?
When we speak about animals, we also talk about birds. There are a lot of birds that are animals and that can even fly. Moreover, birds have unique characteristics that make them different from the others. These features are furcula, feathers, bills, etc. Flying birds give a feel of happiness. So, bird watching is a hobby for many people. You can also enjoy bird watching, with no worries regarding sun tan.
Gaining knowledge about species of animals is an enriching experience for sure.