Although taxonomists disagree about the identity of major animal groups and the relationships among them, most agree that Animalia is monophyletic.
This means that all animals can trace their descent to a single common ancestor.
Radially symmetric animals are the cnidarians, including jellyfish, corals, and anemones, and ctenophores, or comb jellies.
Bilaterally symmetric animals (which include all vertebrates) are further divided based on types of body cavities and variations on the pattern of gastrula formation during development.
Instead, animal cells are held together by structural proteins such as collagen.
All animals, except for the sponges, are made up of cells organized into tissues that are specialized for some function.To give you a better overall experience, we want to provide relevant ads that are more useful to you.For example, when you search for a film, we use your search information and location to show the most relevant cinemas near you.The kingdom Animalia, or Metazoa, includes all animals.Animals are multicellular, eukaryotic organisms, which are heterotrophic, meaning they obtain nutrition from organic sources.This incredible diversity of animal body plans and lifestyles arose in the relatively short period of 40 million years, between 565 and 525 million years ago.All of today's remarkably diverse animal forms are variations on the basic body plans that evolved during the Cambrian. We also use this information to show you ads for similar films you may like in the future.Like Oath, our partners may also show you ads that they think match your interests.The most primitive animal group is the phylum Porifera, the sponges. The remaining animal groups can be divided into radial and bilaterally symmetric animals.