Animales invertebrados

Abstract

Animals are a group of multicellular, eukaryotic, heterotrophic organisms. Most of them are mobile and reproduce sexually. It is one of the kingdoms with the greatest evolution, it describes more than a million species, but the real amount would approach ten million. For the study of the animals are grouped in vertebrates and invertebrates according to the presence or absence of vertebral column. They are distinguished in superior or inferior due to the near to the base of the phylogenetic tree. They are grouped in phyla or divisions that generalize the distinctive characteristics of each one of them.