The animal world is quite diverse. For convenience of study, as well as due to fundamental differences in everything, all types of multicellular animals on Earth were divided into vertebrates and invertebrates.
Vertebrate Animals of the world
Vertebrates are the largest group of living organisms on Earth that can move freely due to the presence of a skeleton.
A characteristic feature of the group of vertebrate animals is the presence of two pairs of members (for fish - fins, for birds - wings, for mammals - legs, etc.).
This type of vertebrate animals make up the majority of the world's animal population. And although all are quite diverse, all are linked by the presence of a skeleton, the dependence on weather conditions and many other common signs. For example, all animals are able to move, breathe, eat. They grow and develop.
To maintain the size of its population, the animals reproduce. Almost all domestic animals that are closely related to human activity are vertebrates. Among vertebrates there are also many pests, for example, mice, hamsters and others.
A prerequisite for all vertebrate animals is the presence of a skeletal or cartilaginous skeleton. This skeleton plays a supporting role in life and helps vertebrates move easily in the characteristic habitat of each class.
Invertebrate animals of the world.
Invertebrate animals are characterized by a simpler structure. These include shellfish, crayfish, worms, arachnids and insects.
Many invertebrate species are parasites of vertebrates and plants. These animals are distributed unequally throughout the world.
Invertebrates play an important role in the biosphere. For example, the solid remains of many ancient invertebrate species, which lived in earlier historical epochs, became part of several geological rocks.
Invertebrates are not of little importance to humans. Man eats many species of these animals.
How to explain the classification of animals in vertebrates and invertebrates for children?
In general, vertebrate and invertebrate animals perform their unique functions in the biosphere, but each of these functions is crucial for life on Earth.
Posted from my blog with SteemPress : http://deisip67.vornix.blog/2018/12/31/classification-of-animals-in-vertebrates-and-invertebrates-video-for-children/