Category: Diversity of Animals

Features of the Animal Kingdom Animals constitute a diverse kingdom of organisms. Although animals range in complexity from simplesea sponges to human beings, most members share certain features. Animals are eukaryotic,multicellular, heterotrophic organisms that ingest their food and usually develop into motile creatureswith a fixed body plan. Most members of the animal kingdom have differentiated…

Vertebrates are among the most recognizable organisms of the animal kingdom (Figure 15.36). Morethan 62,000 vertebrate species have been identified. The vertebrate species now living represent only asmall portion of the vertebrates that have existed. The best-known extinct vertebrates are the dinosaurs,a unique group of reptiles, reaching sizes not seen before or since in terrestrial…

Deuterostomes include the phyla Echinodermata and Chordata (which includes the vertebrates) and twosmaller phyla. Deuterostomes share similar patterns of early development. Echinoderms Echinodermata are named for their spiny skin (from the Greek “echinos” meaning “spiny” and “dermos”meaning “skin”). The phylum includes about 7,000[5]described living species, such as sea stars, seacucumbers, sea urchins, sand dollars, and…

The mollusks are a diverse group (85,000 described species) of mostly marine species. They have avariety of forms, ranging from large predatory squid and octopus, some of which show a high degreeof intelligence, to small grazing forms with elaborately sculpted and colored shells. The annelidstraditionally include the oligochaetes, which include the earthworms and leeches, the…

The animal phyla of this and subsequent modules are triploblastic and have an embryonic mesodermsandwiched between the ectoderm and endoderm. These phyla are also bilaterally symmetrical, meaningthat a longitudinal section will divide them into right and left sides that are mirror images of eachother. Associated with bilateralism is the beginning of cephalization, the evolution of…

The kingdom of animals is informally divided into invertebrate animals, those without a backbone, andvertebrate animals, those with a backbone. Although in general we are most familiar with vertebrateanimals, the vast majority of animal species, about 95 percent, are invertebrates. Invertebrates includea huge diversity of animals, millions of species in about 32 phyla, which we…

Even though members of the animal kingdom are incredibly diverse, animals share common features thatdistinguish them from organisms in other kingdoms. All animals are eukaryotic, multicellular organisms,and almost all animals have specialized tissues. Most animals are motile, at least during certain lifestages. Animals require a source of food to grow and develop. All animals are…

Figure 15.1 The leaf chameleon (Brookesia micra) was discovered in northern Madagascar in 2012.At just over one inch long, it is the smallest known chameleon. Introduction While we can easily identify dogs, lizards, fish, spiders, and worms as animals, other animals, suchas corals and sponges, might be easily mistaken as plants or some other form…