The groups and classification of animals are numerous. In biology we can classify organisms based on their structure and genetics. All animals share a number of important characteristics. Animals are classified depending on whether they have backbones or not. All animals that have bones and backbones are called vertebrates. Those without a column are called invertebrates.
How are animals classified according to their structure?
Vertebrates
They have bones and a spine, being made up of a head, trunk and extremities . Many vertebrates even have tails. Depending on the animal, its body heals in a different way. Mammals have hair, birds have feathers, and fish or reptiles have scales. In the case of amphibians, their skin is bare.
Mammals
Vertebrate animals. They differ by having hairs on the surface of the body. In many of the mammalian species, females have breasts , through which the milk that is generated in their glands comes out, but there are also other species that do not have breasts.
Birds
They are also vertebrates and they stay on the hind limbs, the forelimbs being modified like those, which to fly although not all can do so. Its body is covered with feathers . To reproduce, they lay eggs.
Fishes
Vertebrate animals, but aquatic, being covered with scales and have fins , which allow them to live in water. The same can be said of the bránquias, with which they capture the oxygen dissolved in water.
Reptiles
Other vertebrate animals. There are 7000 different species that are classified into four groups: lizards and snakes, crocodiles, turtles and tuátaras .
Amphibians
Other vertebrates with gill-like respiration in the larval phase and reaching the pulmonary stage when they are adults. It differs from the rest of vertebrates by the transformation they undergo when they develop .
Invertebrates
They are all animals that lack a backbone, although they have an internal skeleton of greater or lesser rigidity. They adapted to all possible life forms , from those found at the bottom of the sea to in the high mountains. They are one of the oldest species and also one of the most numerous. Among the main groups are the porifers (spongiaries), the cnidarians (coelenterates), the mollusks, the annelids, arthropods and echinoderms.
The groups and classification of the animals vary depending on what we want to do the classification on. In this sense, that of vertebrates and invertebrates is one of the most used.
Classification of animals based on their diet
There are three types of animals according to their diet.
Herbivores
Herbivorous animals feed on material of plant origin. They are also called primary consumers , and are the food of a large number of carnivorous animals, so they run very fast and live in large groups. They hardly use energy to get food, but they need a lot of food.
Carnivores
As its name suggests, carnivorous animals are those that feed on animal matter. They assimilate practically 100% of the food they eat , so they need very little food. Something to keep in mind is that they spend a lot of energy to get food, so they usually spend a good part of their time resting.
There are two types of carnivores. On the one hand, predators , who obtain food from live prey by hunting. And, on the other hand, scavengers, whose main source of food is dead animals.
Omnivores
Omnivores do not exist as such, and the most frequent classification is one that establishes the following types of omnivores based on their habitat .
The most common terrestrial omnivores are humans and wild boar , among many others. Among the aquatic ones are piranhas. There are also flying omnivores such as magpies.
Classification of animals according to habitat
The habitat of animals is defined as the area where they live. Over time they have evolved to adapt to the most diverse conditions.
- Terrestrial animals: terrestrial animals are those that can move along the ground. The terrestrial areas where the animals are found are the forest, the jungle, the desert … There are also air-ground animals, those that, despite the fact that they can fly, in certain circumstances, such as eating or mating.
- Aquatic Animals: Aquatic animals spend most of their time in the water. Some can breathe safely underwater, and others need to rise to the surface. The aquatic-terrestrial are the species that are maintained in both habitats.
- Aerial animals: as their name suggests, they are animals that spend their lives flying, such as eagles.
