July 6, 2022
Birds (Aves) are even-tempered, egg-laying and feathered vertebrates, whose wings give most of them the ability to fly. More than 9,000 species of birds are known. Based on the fossil record, birds evolved from dinosaurs in the Jurassic period, and they are classified as theropod subgroups. Feathers and molts for birds evolved from scales to aid in flight and to insulate and dissipate heat. Over time, they began to enable flying as well. Nowadays, there are also flightless birds, but they are also descended from flying strains. Bird species are very similar to each other, and all species have the same basic structure. Birds have beaks but no teeth. The forelimbs have turned into wings, and most birds can fly. The bird's circulatory and respiratory organs are very well developed. The bones are hollow and light. The vision of birds is very precise, the field of vision is wide and the color vision is highly developed. Some species have a magnetic sense. Birds are quite long-lived for their size, and some species are highly intelligent. There is a huge range of different bird species' food and its procurement methods, but the species are usually structurally specialized in a certain type of food and food procurement method. Birds reproduce by laying eggs. Some species build a nest for their eggs, but others lay their eggs on bare ground. It is typical for birds to choose a mate that dogs compete for females with their song or plumage. Many sparrows are known for their versatile song. Many species that spend their summer in polar regions are migratory birds that fly to warmer regions for the winter. Man raises birds for food and eggs. Soft feathers or down are used as stuffing and excrement as fertilizer. Birds are also useful by spreading seeds and pollinating plants. On the other hand, birds can cause a lot of damage to, for example, agriculture. Birds can be enjoyed in many ways, for example by observing them, hunting them or keeping them as pets.