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The blue whale (Balaenoptera musculus) is the largest animal that has ever lived, weighing up to 190 tonnes and measuring up to 33.6 metres (110 ft) long. The largest extant terrestrial animal is the African bush elephant (Loxodonta africana), weighing up to 12.25 tonnes and measuring up to 10.67 metres (35.0 ft) long.
- Overview
- The animal kingdom
Animals are multicellular eukaryotes whose cells are bound together by collagen. Animals dominate human conceptions of life on Earth because of their size, diversity, abundance, and mobility. The presence of muscles and mobility is one of the primary characteristics of the animal kingdom.
What are the two major groups of animals?
The two major groups of animals are vertebrates and invertebrates. Vertebrates have backbones, and invertebrates do not.
When did animals first appear?
Animals first appeared in the Ediacaran Period, about 635 million to 541 million years ago, as soft-bodied forms that left traces of their bodies in shallow-water sediments.
What are the basic functional systems of animals?
Animals evolved from unicellular eukaryotes. The presence of a nuclear membrane in eukaryotes permits separation of the two phases of protein synthesis: transcription (copying) of deoxyribonucleic acid (DNA) in the nucleus and translation (decoding) of the message into protein in the cytoplasm. Compared to the structure of the bacterial cell, this ...
Explore the fascinating world of animals with National Geographic, from cockroaches to orcas, from fireflies to sperm whales. Learn about their behavior, ecology, conservation, and more with photos, videos, and articles.
Learn about any animal using the search box or browse by type, continent, or name. Discover the wonders of the natural world with facts, pictures, definitions, and more on A-Z Animals.
Explore the diversity and wonder of the animal kingdom with Animalia, a comprehensive online encyclopedia. Learn about mammals, birds, reptiles, amphibians, mollusks, fish, insects and more, with facts, photos and videos.
Explore the diversity and wonder of animals with pictures, videos, facts, news, and more from National Geographic. Discover the latest stories, videos, and photos of amphibians, birds, fish, invertebrates, mammals, reptiles, and more.
Weird But True: Marine Animals. Weird But True: Marine Animals. Penguin facts and photos
