Bilateria is a large clade or infrakingdom of animals called bilaterians, characterized by bilateral symmetry during embryonic development. This means their body plans are laid around a longitudinal axis with a front and a rear end, as well as a left–right–symmetrical belly (ventral) and back (dorsal) surface. Nearly all bilaterians maintain a bilaterally symmetrical body as adults; the most notable exception is the echinoderms, which extend to pentaradial symmetry as adults, but are only bilaterally symmetrical as an embryo. Cephalization is also a characteristic feature among most bilaterians, where the special sense organs and central nerve ganglia become concentrated at the front/rostral end.
This page features lists of species and organisms that have become extinct. The reasons for extinction range from natural occurrences, such as shifts in the Earth's ecosystem or natural disasters, to human influences on nature by the overuse of natural resources, hunting and destruction of natural habitats.
Acoelomorpha is a subphylum of very simple and small soft-bodied animals with planula-like features which live in marine or brackish waters. They usually live between grains of sediment, swimming as plankton, or crawling on other organisms, such as algae and corals. With the exception of two acoel freshwater species, all known acoelomorphs are marine.
Xenoturbella is a genus of very simple bilaterians up to a few centimeters long. It contains a small number of marine benthic worm-like species.
On 29 January 2010, the IUCN Red List of Threatened Species identified 5220 endangered species, subspecies and varieties, stocks and sub-populations.
Version 2014.2 of the IUCN Red List of Threatened Species identified 4574 Critically Endangered species, subspecies and varieties, stocks and subpopulations.
The fauna of Canada consist of approximately 200 mammal species, over 460 native bird species, 43 amphibian species, 43 reptile species, and 1,200 fish species. The biology survey of Canada cites that there are approximately 55,000 species of insects, and 11,000 species of mites and spiders.
Acoela, or the acoels, is an order of small and simple invertebrates in the subphylum Acoelomorpha of phylum Xenacoelomorpha, a deep branching bilaterian group of animals, which resemble flatworms. Historically they were treated as an order of turbellarian flatworms.
The rhinoceros iguana is an endangered species of iguana that is endemic to the Caribbean island of Hispaniola and its surrounding islands. A large lizard, they vary in length from 60 to 136 centimetres, and skin colours range from a steely grey to a dark green and even brown. Their name derives from the bony-plated pseudo-horn or outgrowth which resembles the horn of a rhinoceros on the iguana's snout. It is known to coexist with the Ricord's iguana ; the two species are the only taxa of rock iguana to do so.
The following outline is provided as an overview of and topical guide to zoology:
The wildlife of Cambodia is very diverse with at least 162 mammal species, 600 bird species, 176 reptile species, 900 freshwater fish species, 670 invertebrate species, and more than 3000 plant species. A single protected area, Keo Seima Wildlife Sanctuary, is known to support more than 950 total species, including 75 species that are listed as globally threatened on the IUCN Red List. An unknown amount of species remains to be described by science, especially the insect group of butterflies and moths, collectively known as lepidopterans.
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Animals form a clade, meaning they arose from a single common ancestor.
Ambulacraria, or Coelomopora, is a clade of invertebrate phyla that includes echinoderms and hemichordates; a member of this group is called an ambulacrarian. Phylogenetic analysis suggests the echinoderms and hemichordates separated around 533 million years ago. The Ambulacraria are part of the deuterostomes, a clade that also includes the many Chordata, and the few extinct species belonging to the Vetulicolia.
The urbilaterian is the hypothetical last common ancestor of the bilaterian clade, i.e., all animals having a bilateral symmetry.
Deuterostomes are bilaterian animals of the superphylum Deuterostomia, typically characterized by their anus forming before the mouth during embryonic development. Deuterostomia is further divided into 4 phyla: Chordata, Echinodermata, Hemichordata, and the extinct Vetulicolia known from Cambrian fossils. The extinct clade Cambroernida is also thought to be a member of Deuterostomia.
This is a list of lists of notable fictional animals.
Xenacoelomorpha is a small phylum of bilaterian invertebrate animals, consisting of two sister groups: xenoturbellids and acoelomorphs. This new phylum was named in February 2011 and suggested based on morphological synapomorphies, which was then confirmed by phylogenomic analyses of molecular data.
Xenoturbella bocki is a marine benthic worm-like species from the genus Xenoturbella. It is found in saltwater sea floor habitats off the coast of Europe, predominantly Sweden. It was the first species in the genus discovered. Initially it was collected by Swedish zoologist Sixten Bock in 1915, and described in 1949 by Swedish zoologist Einar Westblad. The unusual digestive structure of this species, in which a single opening is used to eat food and excrete waste, has led to considerable study and controversy as to its classification. It is a bottom-dwelling, burrowing carnivore that eats mollusks.
There are several lists of individual animals on Wikipedia. These are lists of notable, non-fictional, specific animals.
The following are lists of prehistoric animals:
