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List Of Chordate Orders

List of chordate orders

This is a list of biological orders in the scientific classification of chordates. :this is a work-in-progress: please use the same layout as the entries below for new additions

Animalia (Animals)

Phylum Chordata

Class Acanthodii - extinct

Class Actinistia (coelacanths)

Class Actinopterygii (ray-finned fish)

Class Amphibia (amphibians)

- Urodela or Caudata (salamanders)
- Anura (frogs and toads)
- Gymnophiona or Apoda (caecilians)

Class Ascideiacea (ascideans and sessile tunicates)

- Enterogona
- Pleurogona
- Aspiraculata
- Phlebobranchia
- Aplousobranchia
- Stalidobranchia

Class Aves (birds)

- Struthioniformes, Ostrich, emus, kiwis, and allies
- Tinamiformes, tinamous
- Sphenisciformes, penguins
- Gaviiformes, loons
- Podicipediformes, grebes
- Procellariiformes, albatrosses, petrels, and allies
- Pelecaniformes, pelicans and allies
- Ciconiiformes, storks and allies
- Phoenicopteriformes, flamingos
- Anseriformes, waterfowl
- Accipitriformes, eagles, hawks and allies (taxonomists have traditionally placed these groups in the Falconiformes)
- Falconiformes, falcons
- Galliformes, fowl
- Turniciformes, button-quail
- Opisthocomiformes, Hoatzin (this enigmatic bird was traditionally treated as a family within either the Galliformes or Cuculiformes)
- Gruiformes, cranes and allies
- Charadriiformes, plovers and allies
- Pterocliformes, sandgrouse (this enigmatic group was traditionally treated as a family in any of three different orders: Charadriiformes, Ciconiiformes, and Columbiformes)
- Columbiformes, doves and pigeons
- Psittaciformes, parrots and allies
- Cuculiformes, cuckoos
- Strigiformes, owls
- Caprimulgiformes, nightjars and allies
- Apodiformes, swifts
- Coliiformes, mousebirds
- Trogoniformes, trogons
- Coraciiformes, kingfishers
- Galbuliformes, jacamars and puffbirds (these groups were traditionally treated as families in the order Piciformes)
- Piciformes, woodpeckers and allies
- Passeriformes, passerines

Class Chondrichthyes (cartilagenous fish)

- Chimaeriformes: chimaeras
- Heterodontiformes: bullhead sharks
- Orectolobiformes: carpet sharks
- Carcharhiniformes: ground sharks
- Lamniformes: mackerel sharks
- Hexanchiformes: frilled and cow sharks
- Squaliformes: dogfish sharks
- Squatiniformes: angel sharks
- Pristiophoriformes: saw sharks
- Rajiformes: rays and skates

Class Dipnoi (lungfish)

Class Larvacea

Class Mammalia (mammals)

- Monotremata: monotremes
- Didelphimorphia: opossums
- Paucituberculata: rat opossums
- Microbiotheria: Monito del Monte
- Dasyuromorphia: marsupial carnivores
- Peramelemorphia: marsupial omnivores
- Notoryctemorphia: marsupial moles
- Diprotodontia: marsupial herbivores; kangaroos, wallabies, possums and allies
- Afrosoricida: tenrecs and golden moles
- Macroscelidea: elephant shrews
- Tubulidentata: Aardvark
- Hyracoidea: hyraxes
- Proboscidea: elephants
- Sirenia: manatees and dugongs
- Xenarthra (formerly Edentata): sloths, armadillos and anteaters
- Dermoptera: colugos
- Scandentia: tree shrews
- Primates: monkeys, apes and allies
- Rodentia: rodents
- Lagomorpha: rabbits, hares and pikas
- Insectivora: shrews, moles, hedgehogs
- Chiroptera: bats
- Pholidota: pangolins
- Carnivora: carnivores; cats, dogs, bears, seals, sea lions and others
- Perissodactyla: odd-toed ungulates; horses, rhinos, tapirs
- Artiodactyla: even-toed ungulates: antelopes, cattle, giraffes, camels, pigs, hippos, sheep, goats
- Cetacea: whales, dolphins, and porpoises

Class Petromyzontida (lampreys)

Class Placodermi - extinct

Class Reptilia (reptiles)

- Crocodilia (Crocodilians)
- Rhynchocephalia (Tuataras)
- Squamata (Lizards, Snakes)
- Testudines (Turtles and their kin)

Class Thaliacea (pelagic tunicates)

- Doliolida
- Pyrosomida
- Salpida, salps Chordate orders

Chordate

- Subphylum Urochordata - Tunicatas
- Ascidiacea
- Thaliacea
- Larvacea
- Subphylum Cephalochordata - Lancelets
- Subphylum Myxini - Hagfishes
- Subphylum Vertebrata - Vertebrates
- Petromyzontida - Lampreys
- Placodermi (extinct)
- Chondrichthyes - Cartilaginous fishes
- Acanthodii (extinct)
- Actinopterygii - Ray-finned fishes
- Actinistia - Coelacanths
- Dipnoi - Lungfishes
- Amphibia - Amphibians
- Reptilia - Reptiles
- Aves - Birds
- Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with several closely related invertebrates. They are united by having, at some stage in their life, a notochord, a hollow dorsal nerve cord, pharyngeal slits, a dorsal hollow neural tube, and a muscular tail extending past the anus. Some scientists argue, however, that the true qualifier should be pharyngeal pouches rather than slits. The phylum Chordata is broken down into three subphyla: Urochordata, Cephalochordata, and Vertebrata. Urochordate larvae have a notochord and a nerve cord but they are lost in adulthood. Cephalochordates have a notochord and a nerve cord but no vertebrae. In vertebrates, the notochord has been replaced by a bony vertebral column. The extant groups of chordates are related as shown in the phylogenetic tree, below. They do not match up very well with the traditional groups, and as a result vertebrate classification is in a state of flux, although their relationships are very well understood. Chordata
- Urochordata (tunicates)
- Cephalochordata (lancelets)
- Craniata (animals with skulls)
- Myxini or Hyperotreti (hagfish)
- Vertebrata (animals with backbones)
- Cephalaspidomorphi (lampreys)
- Gnathostomata (jawed vertebrates)
- Chondrichthyes (cartilaginous fish)
- Teleostomi (bony fish, ~ Osteichthyes)
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- Actinopterygii (ray-finned fish)
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- Sarcopterygii (lobe-finned fish)
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- Actinistia (coelacanths)
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- Dipnoi (lungfishes)
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- Tetrapoda (four-legged vertebrates)
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- Amphibia (amphibians)
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- Amniotes (amniotic egg)
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-
- Synapsida
-
-
- Mammalia (mammals)
-
-
- Anapsida
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- Testudines (turtles)
-
-
- Diapsida
-
-
- Reptilia (most modern reptiles)
-
-
- Lepidosauria (lizards, snakes, tuatara)
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-
- Archosauria
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- Crocodilia (crocodiles, alligators, caimans, gharials)
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- Dinosauria
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- Aves (birds) Chordates ko:척색동물 ja:脊索動物 th:สัตว์มีแกนสันหลัง

Animal

:For the Muppet Show character, see Animal (Muppet). For the professional wrestler, see Joseph Laurinaitis.

- Porifera (sponges)
- Ctenophora (comb jellies)
- Cnidaria (coral, jellyfish, anenomes)
- Placozoa (trichoplax)
- Subregnum Bilateria (bilateral symmetry)
- Acoelomorpha (basal)
- Orthonectida (flatworms, echinoderms, etc.)
- Rhombozoa (dicyemids)
- Myxozoa (slime animals)
- Superphylum Deuterostomia (blastopore becomes anus)
- Chordata (vertebrates, etc.)
- Hemichordata (acorn worms)
- Echinodermata (starfish, urchins)
- Chaetognatha (arrow worms)
- Superphylum Ecdysozoa (shed exoskeleton)
- Kinorhyncha (mud dragons)
- Loricifera
- Priapulida (priapulid worms)
- Nematoda (roundworms)
- Nematomorpha (horsehair worms)
- Onychophora (velvet worms)
- Tardigrada (water bears)
- Arthropoda (insects, etc.)
- Superphylum Platyzoa
- Platyhelminthes (flatworms)
- Gastrotricha (gastrotrichs)
- Rotifera (rotifers)
- Acanthocephala (acanthocephalans)
- Gnathostomulida (jaw worms)
- Micrognathozoa (limnognathia)
- Cycliophora (pandora)
- Superphylum Lophotrochozoa (trochophore larvae / lophophores)
- Sipuncula (peanut worms)
- Nemertea (ribbon worms)
- Phoronida (horseshoe worms)
- Ectoprocta (moss animals)
- Entoprocta (goblet worms)
- Brachiopoda (brachipods)
- Mollusca (mollusks)
- Annelida (segmented worms) Animals are a major group of organisms, classified as the kingdom Animalia or Metazoa. In general they are multicellular, capable of locomotion and responsive to their environment, and feed by consuming other organisms. Their body plan becomes fixed as they develop, usually early on in their development as embryos, although some undergo a process of metamorphosis later on. Along with sponges, gastropods, emus, dolphins and all other animals, Homo sapiens sapiens meet all the criteria above for membership in the group of organisms known as animals and they do not meet the criteria of the other groups. Some humans often consider themselves separate from animals, not on the grounds of biology, but through the use of "other contexts". Whilst self-delusion may be a unique characteristic of the human species it is not cause for exclusion from the Kingdom Animalia. The name animal comes from the Latin word animal, of which animalia is the plural, and ultimately from anima, meaning vital breath or soul.

Characteristics

Aristotle divided the living world between animals and plants, and this was followed by Carolus Linnaeus in the first hierarchical classification. Since then biologists have begun emphasizing evolutionary relationships, and so these groups have been restricted somewhat. For instance, microscopic protozoa were originally considered animals because they move, but are now treated separately. Kingdom Animalia has several characteristics that set it apart from other living things. First, animals are eukaryotic. This separates them from the Kingdom Monera. Second, animals are multicellular, which separates them from Kingdom Protista. Third, they are heterotrophic, setting them apart from Kingdom Plantae and several plant-like protists. Finally, Kingdom Animalia consists of organisms without cell walls, which makes it unique compared to Kingdom Plantae, algae, and Kingdom Fungi.

Structure

With a few exceptions, most notably the sponges (Phylum Porifera), animals have bodies differentiated into separate tissues. These include muscles, which are able to contract and control locomotion, and a nervous system, which sends and processes signals. There is also typically an internal digestive chamber, with one or two openings. Animals with this sort of organization are called metazoans, or eumetazoans when the former is used for animals in general. All animals have eukaryotic cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. This may be calcified to form structures like shells, bones, and spicules. During development it forms a relatively flexible framework upon which cells can move about and be reorganized, making complex structures possible. In contrast, other multicellular organisms like plants and fungi have cells held in place by cell walls, so develop by progressive growth. Also, unique to animal cells are the following intercellular junctions: tight junctions, gap junctions, and desmosomes.

Reproduction and development

Nearly all animals undergo some form of sexual reproduction. Adults are diploid or occasionally polyploid. They have a few specialized reproductive cells, which undergo meiosis to produce smaller motile spermatozoa or larger non-motile ova. These fuse to form zygotes, which develop into new individuals. Many animals are also capable of asexual reproduction. This may take place through parthenogenesis, where fertile eggs are produced without mating, or in some cases through fragmentation. A zygote initially develops into a hollow sphere, called a blastula, which undergoes rearrangement and differentiation. In sponges, blastula larvae swim to a new location and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber, and two separate germ layers - an external ectoderm and an internal endoderm. In most cases, a mesoderm also develops between them. These germ layers then differentiate to form tissues and organs. Animals grow by indirectly using the energy of sunlight. Plants use this energy to turn air into simple sugars using a process known as photosynthesis. These sugars are then used as the building blocks which allow the plant to grow. When animals eat these plants (or eat other animals which have eaten plants), the sugars produced by the plant are used by the animal. They are either used directly to help the animal grow, or broken down, releasing stored solar energy, and giving the animal the energy required for motion. This process is known as glycolysis.

Origin and fossil record

Animals are generally considered to have evolved from flagellate protozoa. Their closest living relatives are the choanoflagellates, collared flagellates that have the same structure as certain sponge cells do. Molecular studies place them in a supergroup called the opisthokonts, which also include the fungi and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal sperm, whereas other eukaryotes tend to have anterior flagella. The first fossils that might represent animals appear towards the end of the Precambrian, around 600 million years ago, and are known as the Vendian biota. These are difficult to relate to later fossils, however. Some may represent precursors of modern phyla, but they may be separate groups, and it is possible they are not really animals at all. Aside from them, most animal phyla with known phyla make a more or less simultaneous appearance during the Cambrian period, about 570 million years ago. It is still disputed whether this event, called the Cambrian explosion, represents a rapid divergence between different groups or a change in conditions that made fossilization possible.

Groups of animals

The sponges (Porifera) diverged from other animals early. As mentioned, they lack the complex organization found in most other phyla. Their cells are differentiated, but not organized into distinct tissues. Sponges are sessile and typically feed by drawing in water through pores all over the body, which is supported by a skeleton typically divided into spicules. The extinct Archaeocyatha, which have fused skeletons, may represent sponges or a separate phylum. Among the eumetazoan phyla, two are radially symmetric and have digestive chambers with a single opening, which serves as both the mouth and the anus. These are the Cnidaria, which include anemones, corals, and jellyfish, and the Ctenophora or comb jellies. Both have distinct tissues, but they are not organized into organs. There are only two main germ layers, the ectoderm and endoderm, with only scattered cells between them. As such, these animals are sometimes called diploblastic. The tiny phylum Placozoa is similar, but individuals do not have a permanent digestive chamber. The remaining animals form a monophyletic group called the Bilateria. For the most part, they are bilaterally symmetric, and often have a specialized head with feeding and sensory organs. The body is triploblastic, i.e. all three germ layers are well-developed, and tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and there is also an internal body cavity called a coelom or pseudocoelom. There are exceptions to each of these characteristics, however - for instance adult echinoderms are radially symmetric, and certain parasitic worms have extremely simplified body structures. Genetic studies have considerably changed our understanding of the relationships within the Bilateria. Most appear to belong to four major lineages: # Deuterostomes # Ecdysozoa # Platyzoa # Lophotrochozoa In addition to these, there are a few small groups of bilaterians with relatively similar structure that appear to have diverged before these major groups. These include the Acoelomorpha, Rhombozoa, and Orthonectida. The Myxozoa, single-celled parasites that were originally considered Protozoa, are now believed to have developed from the Bilateria as well.

Deuterostomes

Deuterostomes differ from the other Bilateria, called protostomes, in several ways. In both cases there is a complete digestive tract. However, in protostomes the initial opening (the archenteron) develops into the mouth, and an anus forms separately. In deuterostomes this is reversed. In most protostomes cells simply fill in the interior of the gastrula to form the mesoderm, called schizocoelous development, but in deuterostomes it forms through evagination of the endoderm, called enterocoelic pouching. Deuterostomes also have a dorsal, rather than a ventral, nerve chord and their embryos undergo different cleavage. All this suggests the deuterostomes and protostomes are separate, monophyletic lineages. The main phyla of deuterostomes are the Echinodermata and Chordata. The former are radially symmetric and exclusively marine, such as sea stars, sea urchins, and sea cucumbers. The latter are dominated by the vertebrates, animals with backbones. These include fish, amphibians, reptiles, birds, and mammals. In addition to these, the deuterostomes also include the Hemichordata or acorn worms. Although they are not especially prominent today, the important fossil graptolites may belong to this group. The Chaetognatha or arrow worms may also be deuterostomes, but this is less certain.

Ecdysozoa

The Ecdysozoa are protostomes, named after the common trait of growth by moulting or ecdysis. The largest animal phylum belongs here, the Arthropoda, including insects, spiders, crabs, and their kin. All these organisms have a body divided into repeating segments, typically with paired appendages. Two smaller phyla, the Onychophora and Tardigrada, are close relatives of the arthropods and share these traits. The ecdysozoans also include the Nematoda or roundworms, the second largest animal phylum. Roundworms are typically microscopic, and occur in nearly every environment where there is water. A number are important parasites. Smaller phyla related to them are the Nematomorpha or horsehair worms, which are visible to the unaided eye, and the Kinorhyncha, Priapulida, and Loricifera, which are all microscopic. These groups have a reduced coelom, called a pseudocoelom. The remaining two groups of protostomes are sometimes grouped together as the Spiralia, since in both embryos develop with spiral cleavage.

Platyzoa

The Platyzoa include the phylum Platyhelminthes, the flatworms. These were originally considered some of the most primitive Bilateria, but it now appears they developed from more complex ancestors. A number of parasites are included in this group, such as the flukes and tapeworms. Flatworms lack a coelom, as do their closest relatives, the microscopic Gastrotricha. The other platyzoan phyla are microscopic and pseudocoelomate. The most prominent are the Rotifera or rotifers, which are common in aqueous environments. They also include the Acanthocephala or spiny-headed worms, the Gnathostomulida, Micrognathozoa, and possibly the Cycliophora. These groups share the presence of complex jaws, from which they are called the Gnathifera.

Lophotrochozoa

The Lophotrochozoa include two of the most successful animal phyla, the Mollusca and Annelida. The former includes animals such as snails, clams, and squids, and the latter comprises the segmented worms, such as earthworms and leeches. These two groups have long been considered close relatives because of the common presence of trochophore larvae, but the annelids were considered closer to the arthropods, because they are both segmented. Now this is generally considered convergent evolution, owing to many morphological and genetic differences between the two phyla. The Lophotrochozoa also include the Nemertea or ribbon worms, the Sipuncula, and several phyla that have a fan of cilia around the mouth, called a lophophore. These were traditionally grouped together as the lophophorates, but it now appears they are paraphyletic, some closer to the Nemertea and some to the Mollusca and Annelida. They include the Brachiopoda or lamp shells, which are prominent in the fossil record, the Entoprocta, the Phoronida, and possibly the Ectoprocta or moss animals.

History of classification

In Linnaeus' original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, the Chordata, whereas the various other forms have been separated out. The above lists represent our current understanding of the group, though there is some variation from source to source.

Usage of the word animal

In everyday usage animal refers to any member of the animal kingdom that is not a human being, and sometimes excludes insects (although including such arthropods as crabs). This confusion stems primarily from the familiarity with zoo animals, farm animals and pets, not from an analytical distinction between insects, humans and the rest of the animal kingdom.

Examples

Some well-known types of animals, listed by their common names:
- alpaca, ant, antelope, badger, bat, bear, bee, beetle, bird, bison, butterfly, cat, chicken, cockroach, coral, cow, deer, dinosaur, dog, dolphin, earthworm, elephant, elk, fish, fly, fox, frog, giraffe, goat, gorilla, hippopotamus, horse, human, iguana, jellyfish, kangaroo, lion, lizard, llama, lynx, monkey, mouse, nightingale, octopus, owl, ox, parrot, penguin, pig, quail, rabbit, rat, rhinoceros, salamander, scorpion, seahorse, shark, sheep, sloth, snake, spider, squid, starfish, tiger, turtle, urial, vole, whale, wolf, yak, zebra

References

External links

- [http://www.animool.com/animals/index.jsp Animals Search Engine]
- [http://www.wikianimals.com wikianimals.com] - Documenting the animal kingdom
- [http://tolweb.org/tree?group=Animals&contgroup=Eukaryotes Tree of Life]
- [http://www.arkive.org A Multimedia Database of Various UK or Endangered Species]
- [http://freepages.genealogy.rootsweb.com/~wakefield/animals.html Animals and Birds Names] - Large table of words: animal, collective, male, female, young, & home
- [http://www273.pair.com/med/words/animal_adjectives.htm English Animal Adjectives]
- [http://www.georgetown.edu/faculty/ballc/animals/animals.html Sounds of the World's Animals] - animal sounds in many languages
- [http://www.findsounds.com/ FindSounds - Search the Web for Sounds] - sound files including animal sound files
- [http://www.australianfauna.com/ Australian Animals]
- [http://www.animalreviews.com AnimalReviews] - animals reviewed and evaluated
- [http://animals.timduru.org/ The animal photo archive] - Photos of animals
- [http://www.wildlife-photo.org Photo gallery of animals pictures from the entire world.]
- [http://www.wildlife-photo.org/birds_list.htm Birds Name Check List in Latin, English, Russian and Hebrew.]
- [http://www.wildanimalsonline.com Wild Animals Online] - an online encyclopedia of wild animals - facts, photos Category:Animals zh-min-nan:Tōng-bu̍t ko:동물 ms:Haiwan ja:動物 simple:Animal th:สัตว์

Acanthodii

Climatiiformes
Ischnacanthiformes
Acanthodiformes Acanthodii (sometimes called spiny sharks) is a class of extinct fishes, having features of both bony fish ( Osteichthyes) and cartilaginous fish (Chondrichthyes). They appeared in the early Silurian (430 mya) and lasted until the late Permian (250 mya). The earliest ancanthodians were marine, but during the Devonian, freshwater species became predominant. They are distinguished in two respects: they were the first known jawed vertebrates, and they had stout spines supporting their fins, fixed in place and non-movable (like a shark's dorsal fin). There were three orders: Climatiiformes, Ischnacanthiformes and Acanthodiformes. Climatiiforma had shoulder armor and many small sharp spines, Ischnacathiforma with teeth fused to the jaw, and the Acanthodiforma were filter feeders, with no teeth in the jaw, but long gill rakers. Almost all of them were small, slender fish with large eyes, heterocercal tails, with the caudal vertebrae supporting the top lobe of the tail fin, like a shark's tail has today. All had pairs of bony spines along the ventral mid-body line, that often supported a web of tissue between the spine and the body, creating a fin. Thus the "spiny shark" nickname. These distinctive spines give the class its name, from the Greek akanthos. The scales of Acanthodii are unique and used in determining relative age of sedimentary rock. The scales are tiny, with a bulbus base, a neck, and a flat or slightly curved diamond-shaped crown.

References

Long, J.A. The Rise of Fishes: 500 Million Years of Evolution. Johns Hopkins Univ. Press. Baltimore and London. 1995.

External links

http://www.mdgekko.com/devonian/who/pages/acanthodians.html Category:Prehistoric fish

Actinistia

Latimeria chalumnae
Latimeria menadoensis Coelacanth (meaning "hollow spine" in Greek; ) is a species of fish and represents the oldest lineage of living fish known to date. The coelacanth was believed to have been extinct since the end of the Cretaceous period — until a live specimen turned up off the east coast of South Africa off the Chalumna River in 1938. Since then, they have been found in the Comoros, Sulawesi (Indonesia), Kenya, Tanzania, Mozambique, Madagascar and the St. Lucia Marine Protected Area in South Africa.

Biological characteristics

South Africa The coelacanth is a lobe-finned fish with the pectoral and anal fins on fleshy stalks supported by bones, and the tail fin divided into three lobes, the middle one of which also has a stalk. The coelacanth has modified cosmoid scales, which are thinner than true cosmoid scales, which can only be found on extinct fish. Coelacanths were believed to first appear in the Carboniferous Period, about 400-350 million years ago. The coelacanth, which is closely related to lungfishes, used to live in many bodies of water in prehistoric times. The average weight of the coelacanth is 176 pounds (80 kg) and they can reach up to 6.5 feet (2 m) in length. They are the only living species known to have a functional intercranial joint, a type of hinge that aids in the consumption of large prey. Coelacanths are also mucilaginous; their scales release mucus and their bodies continually exude oil. This oil is a laxative, and makes the fish almost inedible unless dried and salted.

Morphology of the coelacanth skeleton

laxative View 3D computed tomographic (CT) imagery of the coelacanth skeleton, including labeled images of the intracranial joint, at [http://digimorph.org/specimens/Latimeria_chalumnae/whole/ Digimorph.org]

Discovery

First find in South Africa

laxative The first hint that western scientists had of a modern, living coelacanth existed was when Marjorie Courtenay-Latimer, who was curator of a museum in East London, South Africa, was inspecting local fish catches for unusual specimens in 1938. She was looking at the catch of a fishing boat that had been fishing for sharks near the Chalumna River and saw an odd blue fish fin in the catch. She pulled the fish out of the pile and brought it to the museum to find out what kind of fish it was. Failing to find it in any of her books, she attempted to contact her friend, Professor James Leonard Brierley Smith, but he was away. Unable to preserve the fish, she sent it to a taxidermist. When Smith returned, he immediately recognized it as a coelacanth, known only from fossils. The species was named Latimeria chalumnae in honour of her and the waters in which it was found. The fish was referred to as a "Living Fossil".

Comoros

A worldwide search was launched for more coelacanths, with a reward of 100 British pounds (a very substantial sum to the average South African fisherman of the time). Fourteen years later, they were found in the Comoros, at first only another single specimen, but later it turned out that the fish was no stranger to local knowledge: the Comorians, in the port of Mutsamudu on the Comorian island of Anjouan, were puzzled that someone would pay big money for what the locals called a gombessa or mame, an inferior (nearly inedible) fish that their fishermen occasionally caught by mistake. They now understand the significance of their endangered species and have a program in place to return any accidentally caught gombessa to deep water so that they can survive. The second specimen, found in 1952 by Comorian fisherman Ahmed Hussain, was originally described as a different species, Malania anjounae (after Daniel François Malan), but it turned out that the lack of the first dorsal fin, which was believed to distinguish it from Latimeria, was due to an injury early in the animal's life. Ironically, Malan was a staunch creationist; on seeing the supposed ancestor of all terrestrial life named after him, his reaction was a startled, "Why it's ugly! Is this where we come from?" Smith, who died in 1968, wrote his account of the coelacanth story in the book Old Fourlegs, first published in 1956. His book Sea Fishes of the Indian Ocean, illustrated and co-authored by his wife Margaret, remains the standard ichthyological reference for the region.

Second species in Indonesia

In 1997, Arnaz and Mark Erdmann were traveling on honeymoon in Indonesia and saw a strange fish entering the market at Manado Tua, on the island of Sulawesi. Arnaz Erdmann recognized it as a gombessa, but it was brown, not blue. (The Erdmanns did not realize this was a new species until an expert saw their photo on the web.) DNA testing revealed that this species, called rajah laut ('King of the Sea') by the Indonesians, is not related to the Comorian population. It was given the scientific name Latimeria menadoensis.

St. Lucia Marine Protected Area in South Africa

In South Africa, the search continued on and off over the years. One diver, 46-year-old Riaan Bouwer, lost his life exploring for coelacanths in June 1998. On October 28th, 2000, just south of the Mozambique border, in Sodwana Bay in the St. Lucia Marine Protected Area, three deep-water divers - Pieter Venter, Peter Timm and Etienne le Roux - made a dive to 104 metres and suddenly spotted a coelacanth. However, they were diving without cameras. The group vowed to return with photographic equipment. Calling themselves SA Coelacanth Expedition 2000, the group returned, this time with several additional members. On November 26 they performed a first dive, but did not witness any coelacanths. The next day, four members of the group - Pieter Venter, Gilbert Gunn, Christo Serfontein and Dennis Harding - went down again. Moving from cavern to cavern, they found three coelacanths. The largest was between 1.5 and 1.8 metres long, the other two 1.2 metres and 1 metre. The fish swam heads down and appeared to be feeding off of ledges. The cameramen took video footage and photos. Then, however, disaster struck. Christo suddenly passed out under water, and 34-year-old Dennis Harding rose to the surface with him in an uncontrolled ascent. Harding complained of neck pains and died in the boat. Apparently, he had suffered a cerebral embolism. Christo recovered after being taken underwater for recompression. However, the find was big news in South Africa. In March-April 2002, the Jago Submersible and Fricke Dive Team descended into the depths off Sodwana and observed 15 coelacanths, one pregnant. Tissue samples were taken using a dart probe.

Taxonomic notes

Coelacanthimorpha or Actinistia are sometimes used to designate the group of Sarcopterygian fishes that contains the Coelacanthiformes.

References

- "Marjorie Courtenay-Latimer." The Daily Telegraph (London). May 19, 2004.
- Myrna Oliver. "Marjorie Courtenay-Latimer, 97; Confirmed Rare Fish's Existence." Los Angeles Times. June 13, 2004. pg. B.16
- Jeremy Pearce. "Marjorie Courtenay-Latimer, Naturalist, Is Dead at 97." New York Times. June 7, 2004. pg. B.6
- Keith S. Thompson. Living Fossil: The Story of the Coelacanth. New York: W.W. Norton, 1991.

External links

- [http://www.acep.co.za/ African Coelacanth Ecosystem Programme], ACEP, as the South African Coelacanth Conservation and Genome Resource Programme
- [http://thestar.com.my/lifestyle/story.asp?file=/2004/8/17/features/8593109&s Living fossil fish in Indonesian waters], article at The Star Online (needs subscription)
- [http://marinebio.org/species.asp?id=54 Coelacanth] at MarineBio.org
- [http://www.cnn.com/TECH/science/9809/23/living.fossil CNN: Coelacanth]
- [http://news.bbc.co.uk/1/hi/sci/tech/1331848.stm BBC: Coelacanth]
- [http://www.pbs.org/wgbh/nova/fish/ PBS: NOVA - Ancient Creature of the Deep] Category:Lobe-finned fish Category:Living fossils ja:シーラカンス JeLiSa

Actinopterygii

Chondrostei
Neopterygii
See text for orders. The Actinopterygii are the ray-finned fish. They are the dominant group of vertebrates, with over 27,000 species ubiquitous throughout fresh water and marine environments.

Classification

Traditionally three grades of Actinopterygii have been recognized: the Chondrostei, Holostei, and Teleostei. The second is paraphyletic and tends to be abandoned, however, while the first is now restricted to those forms closer to extant Chondrostei than to the other groups. Nearly all fish alive today are teleosts. A listing of the different groups is given below, down to the level of orders, arranged in what is believed to represent the evolutionary sequence down to the level of superorder.
- Subclass Chondrostei
- Order Polypteriformes (bichirs)
- Order Acipenseriformes (sturgeons, paddlefish)
- Subclass Neopterygii
- Order Semionotiformes (gars)
- Order Amiiformes (bowfins)
- Infraclass Teleostei
- Superorder Osteoglossomorpha
- Order Osteoglossiformes (bony tongues, etc)
- Order Hiodontiformes (mooneye, etc)
- Superorder Elopomorpha
- Order Elopiformes (tarpons, etc)
- Order Albuliformes (bonefishes)
- Order Notacanthiformes (spiny eels)
- Order Anguilliformes (true eels, gulpers)
- Order Saccopharyngiformes
- Superorder Clupeomorpha
- Order Clupeiformes (herrings & allies)
- Superorder Ostariophysi
- Order Gonorynchiformes
- Order Cypriniformes (minnows & allies)
- Order Characiformes (characins & allies)
- Order Gymnotiformes (electric eels, knifefishes)
- Order Siluriformes (catfishes)
- Superorder Protacanthopterygii
- Order Salmoniformes (salmon & allies)
- Order Esociformes (pikes & allies)
- Order Osmeriformes (smelts & allies)
- Superorder Sternopterygii
- Order Ateleopodiformes (jellynose fishes)
- Order Stomiiformes (dragonfishes & allies)
- Superorder Cyclosquamata
- Order Aulopiformes (lizardfishes)
- Superorder Scopelomorpha
- Order Myctophiformes (lanternfishes)
- Superorder Lampridiomorpha
- Order Lampridiformes (opahs, etc)
- Superorder Polymyxiomorpha
- Order Polymixiiformes (beardfishes)
- Superorder Paracanthopterygii
- Order Percopsiformes (trout-perches & allies)
- Order Batrachoidiformes (toadfishes)
- Order Lophiiformes (goosefishes, etc)
- Order Gadiformes (cods & allies)
- Order Ophidiiformes (cusk eels, etc)
- Superorder Acanthopterygii
- Order Mugiliformes (mullets & allies)
- Order Atheriniformes (silversides & allies)
- Order Beloniformes (needlefishes, etc)
- Order Cetomimiformes (whalefishes)
- Order Cyprinodontiformes (killifishes, etc)
- Order Stephanoberyciformes (pricklefishes, whalefishes, etc)
- Order Beryciformes (alfonsinos, etc)
- Order Zeiformes (dories, etc)
- Order Gasterosteiformes (sticklebacks, pipefishes, seahorses, etc)
- Order Synbranchiformes (swamp-eels, etc)
- Order Tetraodontiformes (triggerfishes & allies)
- Order Pleuronectiformes (flatfishes & allies)
- Order Scorpaeniformes (scorpionfishes & allies)
- Order Perciformes (perches & many allies)

External links

-
- [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?name=actinopterygii NCBI Taxonomy entry]

References

- Category:Bony fish ko:조기어류 ja:条鰭亜綱

Urodela

Cryptobranchoidea
Salamandroidea
Sirenoidea Salamander is the common name applied to approximately 500 amphibian vertebrates with slender bodies, short legs, and long tails (order Caudata or Urodela). The moist skin of the amphibians limits them to habitats either near water or under some protection on moist ground, usually in a forest. Some species are aquatic throughout life, some take to the water intermittently, and some are entirely terrestrial as adults. Salamanders superficially resemble lizards, but are easily distinguished by their lack of scales. They are capable of regenerating lost limbs. Species of salamanders are numerous and found in most moist or aqueous habitats in the northern hemisphere. Most are small but some reach up to 5 feet in length. They live in brooks and ponds and other moist locations. North America has the hellbender and the mudpuppy which can reach the length of a foot or more. In Japan and China the giant salamander is found, which reaches 5 feet (1.5m) and weighs up to 30 kilograms [http://news.xinhuanet.com/newscenter/2002-12/19/content_663873.htm] [http://www.giant-salamander.com/]. Salamanders are generally restricted to the northern hemisphere, with the exception of a few species in the northernmost part of South America.

Mythology

The mythical salamander resembles the real salamander somewhat in appearance, but makes its home in fires, the hotter the better. (Similarly, the salamander in heraldry is shown in flames, but is otherwise depicted as a generic lizard.) Early travelers to China were shown garments which, or so they were told, had been woven of wool from the salamander: the cloth was completely unharmed by fire. The garments had actually been woven from asbestos. Later Paracelsus suggested that the salamander was the elemental of fire. These myths originate in Europe from the fire salamander, Salamandra salamandra, which hibernates in and under rotting logs. When logs were brought indoors and put on the fire, the animals mysteriously appeared from the flames.

Classification

There are ten families belonging to the order Urodela, divided into three suborders:
- Suborder Cryptobranchoidea (giant salamanders)
- Cryptobranchidae (giant salamanders)
- Hynobiidae (Asiatic salamanders)
- Suborder Salamandroidea (advanced salamanders)
- Ambystomatidae (mole salamanders)
- Amphiumidae (amphiumas or Congo eels)
- Dicamptodontidae (Pacific giant salamanders)
- Plethodontidae (lungless salamanders)
- Proteidae (mudpuppies and waterdogs)
- Rhyacotritonidae (torrent salamanders)
- Salamandridae (true salamanders and newts)
- Suborder Sirenoidea (sirens)
- Sirenidae (sirens)

External references

- [http://www.schwanzlurche.de Caudatamedia]
- [http://www.caudata.org/cc Caudata Culture] Category:Amphibians Category:Salamanders ja:サンショウウオ simple:Salamander

Gymnophiona

:See also: Caecilian, bishop of Carthage, 312 C.E.
Rhinatrematidae
Ichthyophiidae
Uraeotyphlidae
Scolecomorphidae
Typhlonectidae
Caeciliidae The Caecilians are an order (Gymnophiona or Apoda) of amphibians which resemble worms or snakes. They mostly live hidden in the ground which makes them the least explored order of amphibians, and widely unknown.

Anatomy

Caecilians' feet have degenerated, making the smaller species resemble worms, while the larger species with lengths up to 1.5 m resemble snakes. The tail is also very short, so the cloaca is near the end of the body. Their skin is smooth and usually dark-matt, but many species also have colorful skins. Inside the skin are calcite scales, which suggests that they are related with the fossil Stegocephalia. However the scales are now believed to be a secondary development, and not directly inherited from Stegocephalia. Due to their underground life the eyes are small and covered by skin for protection, which have led to the misconception that they are blind. However due to the skin cover their visual sense is limited to simple dark-light perception. All Caecilians share two tentacles at their head, which are probably used for a second olfactory capability in addition to the normal sense of smell based in the nose. Except for one lungless species - Typhlonectes eiselti, only known from one specimen collected somewhere in South America - all Caecilians have lungs, but also use the skin or the mouth for oxygen absorption. Often the left lung is much smaller than the right one, an adaptation to body shape also found in snakes.

Distribution

Caecilians are found in most of the tropic areas of South-East Asia, Africa and South America, except the dry areas and the high mountains. In South America their distribution extends well into the temperate north of Argentina. For central Africa no systematic search has been done yet, but it is likely Caecilians are found all over the tropical rainforest there.

Reproduction

Caecilians are the only order of amphibians which only use internal insemination. The male Caecilians have a penis-like organ, the phallodeum, which is inserted into the cloaca of the female for 2 to 3 hours. About 25% of the species are oviparous (egg-laying); the eggs are guarded by the female. For some species the young Caecilians are already metamorphed when they hatch, other hatch as larvae. The larvae aren't fully aquatic, but spend the daytime in the soil near the water. 75% of the species are viviparous, meaning that they give birth to already developed offspring. The fetus is fed inside the female with special cells of the oviduct, which are eaten by the fetus with special scraping teeth.

Origin of the name

The name Caecilian derives from the Latin word caecus = blind, referring to the small or sometimes non-existing eyes. The name dates back to the taxonomic name of the first species described by Carolus Linnaeus, which he gave the name Caecilia tentaculata. The taxonomic name of the order derives from the Greek words γυμνος (gymnos, naked) and οφις (ophis, snake), as the Caecilians were originally thought to be related with snakes.

Taxonomy

Taxonomically the Caecilians are divided into 5 families. The species numbers have to be taken with care, as many of these species are identified on the basis of only one specimen. It is likely that not all species have been described yet, and some of the species described below as different may be combined into one species in a future reclassification.
- Beaked Caecilians (Rhinatrematidae) - 2 genera, 9 species
- Fish Caecilians (Ichthyophiidae) - 2 genera, 39 species
- Indian Caecilians (Uraeotyphlidae) - 1 genus, 5 species
- Tropical Caecilians (Scolecomorphidae) - 2 genera, 6 species
- Aquatic Caecilians (Typhlonectidae) - 5 genera, 13 species
- Common Caecilians (Caeciliidae) - 26 genera, 107 species

Misc

Large Caecilians dubbed "ingots" plagued the French occupation of Indochina in the years before the Vietnam war. The creatures were reported to burrow large holes and disrupt troop movement.

References

- Werner Himstedt, Die Blindwühlen, ISBN 3894324341 (German)

External links

- http://www.caecilian.org Category:Amphibians Category:Caecilians nb:Ormepadde

Ascideiacea

Aplousobranchia
Enterogona
Phlebobranchia
Pleurogona
Stolidobranchia Ascidiacea (commonly known as the ascidians or sea-Squirts) is an class in the Tunicata subphylum of sac-like marine filter feeders. They are characterized by a tough outer "tunic" made of the polysaccharide tunicin whilst other tunicates are much less robust. Whilst adults are sessile (immobile), larvae resemble tadpoles and swim up and down in their marine environment. The larvae undergo a metamorphosis when a suitable place to attach is found. During this metamorphosis, the tail, along with the notochord and neural tube is reabsorbed, thats why tunicates are also referred as "urochordates" (uro=tail). Like other tunicates, they also collect and concentrate vanadium in their blood, although the reason for this behaviour is not properly understood. Examples of ascidians include Sea Tulips and the Solitary Ascidian.

References

External link

- [http://ascidiacea.com/ Ascideiacea.com] - Classification and images of many ascideians. Category:Tunicates

Enterogona

See text. The order Enterogona is in the class Ascideiacea. It describes a group of marine animals.
- Cionidae Category:Tunicates

Aves

Many - see section below. Birds are bipedal, warm-blooded, egg-laying vertebrates characterized primarily by feathers, forelimbs modified as wings, and hollow bones. Birds range in size from the tiny hummingbirds to the huge Ostrich and Emu. Depending on taxonomic viewpoint, there are about 8,800–10,200 living bird species (plus about 120–130 that have become extinct in the span of human history) in the world, making them the most diverse class of terrestrial vertebrates. Birds are a very differentiated class, with some feeding on nectar, plants, seeds, insects, rodents, fish, carrion, or other birds. Most birds are diurnal, or active during the day. Some birds, such as the owls and nightjars, are nocturnal or crepuscular (active during twilight hours). Many birds migrate long distances to utilise optimum habitats (e.g., Arctic Tern) while others spend almost all their time at sea (e.g. the Wandering Albatross). Some, such as frigatebirds, stay aloft for days at a time, even sleeping on the wing. Common characteristics of birds include a bony beak with no teeth, the laying of hard-shelled eggs, high metabolic rate, and a light but strong skeletons. Most birds are characterised by flight, though the ratites are flightless, and several other species, particularly on islands, have also lost this ability. Flightless birds include the penguins, Ostrich, kiwi, and the extinct Dodo. Flightless species are vulnerable to extinction when humans or the mammals they introduce arrive in their habitat, for example the Great Auk, flightless rails, and the moa of New Zealand.

Bird orders

New Zealand This is a list of the taxonomic orders in the class Aves. The list of birds gives a more detailed summary, including families.
- Struthioniformes, Ostrich, emus, kiwis, and allies
- Tinamiformes, tinamous
- Anseriformes, waterfowl
- Galliformes, fowl
- Sphenisciformes, penguins
- Gaviiformes, loons
- Podicipediformes, grebes
- Procellariiformes, albatrosses, petrels, and allies
- Pelecaniformes, pelicans and allies
- Ciconiiformes, storks and allies
- Phoenicopteriformes, flamingos
- Accipitriformes, eagles, hawks and allies
- Falconiformes, falcons
- Turniciformes, button-quail
- Gruiformes, cranes and allies
- Charadriiformes, plovers and allies
- Pteroclidiformes, sandgrouse
- Columbiformes, doves and pigeons
- Psittaciformes, parrots and allies
- Cuculiformes, cuckoos
- Strigiformes, owls
- Caprimulgiformes, nightjars and allies
- Apodiformes, swifts
- Trochiliformes, hummingbirds
- Coraciiformes, kingfishers
- Piciformes, woodpeckers and allies
- Trogoniformes, trogons
- Coliiformes, mousebirds
- Passeriformes, passerines Note: This is the traditional classification (the so-called Clements order). A more recent, radically different classification based on molecular data has been developed (the so-called Sibley order) and is gaining acceptance.

Evolution

Birds are generally considered to have evolved from theropod dinosaurs. Specifically, birds are members of Maniraptora, a group of theropods which includes dromaeosaurs and oviraptorids. As more non-avian theropods that are closely related to birds are discovered, the formerly clear distinction between non-birds and birds becomes less so. Recent discoveries in North-east China (Liaoning Province) demonstrating that many small theropod dinosaurs had feathers contribute to this ambiguity. The basal bird Archaeopteryx, from the Jurassic, is well-known as one of the first "missing links" to be found in support of evolution in the late 19th century. It remains the most primitive known bird. Other Mesozoic birds include the Confuciusornithidae, Enantiornithes, Ichthyornis, and Hesperornithiformes, a group of flightless divers resembling grebes and loons. The recently discovered dromaeosaur, Cryptovolans, was capable of powered flight, contained a keel and had ribs with uncinate processes. In fact, Cryptovolans makes a better "bird" than Archaeopteryx which is missing some of these modern bird features. Because of this, some paleontologists have suggested that dromaeosaurs are actually basal birds whose larger members are secondarily flightless, i.e. dromaeosaurs evolved from birds and not the other way around. Evidence for this theory is currently inconclusive, but digs continue to unearth fossils (especially in China) of the strange feathered dromaeosaurs. It should be noted that although ornithischian (bird-hipped) dinosaurs share the same hip structure as birds, birds actually originated from the saurischian (lizard-hipped) dinosaurs, and thus arrived at their hip structure condition independently. In fact, the bird-like hip structure developed a third time among a peculiar group of theropods, the Therizinosauridae. Modern birds are classified in Neornithes, which are split into the Paleognathae and Neognathae. The paleognaths include the tinamous (found only in Central and South America) and the ratites. The ratites are large flightless birds, and include ostriches, cassowaries, kiwis and emus; some scientists suspect that the ratites represent an artificial grouping of birds which have independently lost the ability to fly, others contend that the ratites never had the ability to fly and are more directly related to the dinosaurs. The basal divergence from the remaining Neognathes was that of the Galloanseri, the superorder containing the Anseriformes (ducks, geese and swans), and the Galliformes (the pheasants, grouse, and their allies). See the chart. The classification of birds is a contentious issue. Sibley & Ahlquist's Phylogeny and Classification of Birds (1990) is a landmark work on the classification of birds (although frequently debated and constantly revised). Evidence for the various orders seems to be fairly good, but the relationships between the orders are in a state of disarray. Evidence from modern bird anatomy, fossils and DNA have all been brought to bear on the problem but no strong consensus has emerged. See also: Sibley-Ahlquist taxonomy.

Reproduction

Although most male birds have no external sex organs, the male does have two testes which become hundreds of times larger during the breeding season to produce sperm. The female's ovaries also become larger, although only the left ovary actually functions. In the males of species without a phallus (see below), sperm is stored within the proctodeum compartment within the cloaca prior to copulation. During copulation, the female moves her tail to the side and the male either mounts the female from behind or moves very close to her. He moves the opening of his cloaca, or vent, close to hers, so that the sperm can enter the female's cloaca, in what is referred to as a cloacal kiss. This can happen very fast, sometimes in less than one second. The sperm is stored in the female's cloaca for anywhere from a week to a year, depending on the species of bird. Then, one by one, eggs will descend from the female's ovaries and become fertilized by the male's sperm, before being subsequently laid by the female. The eggs will then continue their development in the nest. cloacal kiss.]] Many waterfowl and some other birds, such as the ostrich and turkey, do possess a phallus. Except during copulation, it is hidden within the proctodeum compartment within the cloaca, just inside the vent. The avian phallus differs from the mammalian penis in several ways, most importantly in that it is purely a copulatory organ and is not used for dispelling urine. After the eggs hatch, parent birds provide varying degrees of care in terms of food and protection. Precocial birds can care for themselves independently within minutes of hatching; altricial hatchlings are helpless, blind, and naked, and require extended parental care. The chicks of many ground-nesting birds such as partridges and waders are often able to run virtually immediately after hatching; such birds are referred to as nidifugous. The young of hole-nesters, on the other hand, are often totally incapable of unassisted survival. "Fledging" is the process of a chick acquiring feathers until it can fly. Some birds, such as pigeons, geese, and Red-crowned Cranes, remain with their mates for life (or for a long period) and may produce offspring on a regular basis.

Mating systems and parental care

Sources for this section include:
- Gowaty, Patricia Adair: Male Parental Care and Apparent Monogamy among Eastern Bluebirds (Sialia Sialis). The American Naturalist 121(2): 149-160 (1983).
- Ketterson, Ellen D. and Nolan, Val: Male Parental Behavior in Birds. Annual Review of Ecology and Systematics 25: 601-28 (1994).
- Zeveloff, Samuel and Boyce, Mark: Parental Investment and Mating Systems in Mammals. Evolution 34(5): 973-982 (1980).

The three predominant mating systems are polyandry, polygyny, and monogamy. Monogamy is seen in approximately 91% of all bird species. Polygyny constitutes 2% of all birds and polyandry is seen in less than 1%. Monogamous species of males and females pair for the breeding season. In some cases, the individuals may pair for life. One reason for the high rate of monogamy among birds is due to the fact that male birds are just as adept at parental care as females. In most groups of animals, male parental care is rare, but in birds it is quite common; it is more extensive in birds than in any other vertebrate class. In fact, male care can be seen as important or essential to female fitness. "In one form of monogamy such as with obligate monogamy a female cannot rear a litter without the aid of a male" (Gowaty, 1983). obligate The parental behavior most associated with monogamy was male incubation. This is very interesting, because male incubation is the most confining male parental behavior. It not only consumes time, but also may require physiological changes that interfere with usual mating. With the extreme loss of mating opportunities, there is a reduction in the reproductive success among males. "This information then suggests that sexual selection may be less intense in taxa where males incubate, hypothetically because males allocate more effort to parental care and less to mating" (Ketterson and Nolan, 1994). It is understood then that the females associated with these males base their choice of mate on parental behaviors rather than physical appearance.

Respiration

Birds respire by means of crosscurrent flow: the air flows at a 90° angle to the flow of blood in the lungs' capillaries. In addition to the lungs themselves, birds have posterior and anterior air sacs (typically nine) which control air flow through the lungs, but do not play a direct role in gas exchange. There are three parts involved in respiration:
- the anterior air sacs (interclavicular, cervicals, and anterior thoracics),
- the lungs, and
- the posterior air sacs (posterior thoracics and abdominals). It takes a bird two full breaths, to completely cycle the air from each inhalation through the lungs and out again. The air flows through the air sacs and lungs as follows:
- First inhalation: air flows through the trachea and bronchi into the posterior air sacs.
- First exhalation: air flows from the posterior air sacs to the lungs.
- Second inhalation: air flows from the lungs to the anterior air sacs.
- Second exhalation: air flows from the anterior sacs back through the trachea and out of the body. Since during inhalation and exhalation fresh air flows through the lungs in only one direction, birds are able to diffuse more oxygen into their blood. Unlike humans and other mammals, there is no mixing of oxygen rich air and carbon dioxide rich air. Thus, the partial pressure of oxygen in a bird's lungs is the same as the environment. This is why you would more likely see a bird on Mount Everest than, say, a mouse. Avian lungs do not have alveoli, as mammalian lungs do, but instead contain millions of tiny passages known as parabronchi, connected at either ends by the dorsobronchi and ventrobronchi. Air flows through the honeycombed walls of the parabronchi and into air capillaries, where oxygen and carbon dioxide are traded with cross-flowing blood capillaries by diffusion.

Other anatomy

mouse Birds possess a ventriculus, or gizzard, that is composed of four muscular bands that act to rotate and crush food by shifting the food from one area to the next within the gizzard. Depending on the species, the gizzard may contain small pieces of grit or stone that the bird has swallowed to aid in the grinding process of digestion. For birds in captivity, only certain species of birds require grit in their diet for digestion. The use of gizzard stones is a similarity between birds and dinosaurs, which left gizzard stones called gastroliths as trace fossils. Birds also have skeletons possessing unique characteristics. See bird skeleton. The region between the eye and bill on the side of a bird's head is called a lore. This region is sometimes featherless, and the skin may be tinted (as in many species of the cormorant family).

Birds and humans

cormorant cormorant cormorant Birds are an important food source for humans. The most commonly eaten species is the domestic chicken and its eggs, although geese, pheasants, turkeys, and ducks are also widely eaten. Other birds that have been utilized for food include emus, ostriches, pigeons, grouse, quails, doves, woodcocks, songbirds, and others, including small passerines such as finches. At one time swans and flamingos were delicacies of the rich and powerful, although these are generally protected now. Many species have become extinct through over-hunting, such as the Passenger Pigeon, and many others have become endangered or extinct through habitat destruction, deforestation and intensive agriculture being common causes for declines. Numerous species have come to depend on human activities for food and are widespread to the point of being pests. For example the common pigeon or Rock Dove (Columba livia) thrives in urban areas around the world. In North America, introduced House Sparrows, Common Starlings, and House Finches are similarly widespread. Other birds have been used by humans: for example Homing pigeons to carry messages (many are still kept for sport), falcons for hunting, cormorants for fishing. Chickens and pigeons are popular subjects in experimental research in biology and comparative psychology. As birds are extra-sensitive to toxins, the Canary was often used in coal mines to indicate the presence of poisonous gases, so that the miners could escape. Colorful, particularly tropical, birds (e.g., parrots, and mynahs) are often kept as pets although this has led to smuggling of some endangered species; CITES does considerable work to deter this. Bird diseases that can be contracted by humans include these: psittacosis, salmonellosis, campylobacteriosis, Newcastle's disease, mycobacteriosis (avian tuberculosis), avian influenza, giardiasis, and cryptosporiadiosis.

Trivia

- To preen or groom their feathers, birds use their bills to brush away foreign particles.
- The birds of a region are called the avifauna.
- Few birds use chemical defences against predators. Tubenoses can eject an unpleasant slime against an aggressor, and some species of pitohui, found in New Guinea secrete a powerful neurotoxin in their feathers.
- Birds are among the most extensively studied animal groups, with hundreds of academic journals devoted to their study.

References and external links

- [http://www.bsc-eoc.org/avibase/avibase.jsp?lang=EN&pg=home Avibase - The World Bird Database]
- [http://www.i-o-c.org/IOComm/index.htm International Ornithological Committee]
- [http://www.birdlife.org/ Birdlife International] - Dedicated to bird conservation worldwide; has a database with about 250,000 records on endangered bird species
- [http://birdingonthe.net/ Birdingonthe.net]
- [http://www.surfbirds.com/ Surfbirds Birdwatching and World Birding]
- [http://worldtwitch.com/ Worldtwitch - rare bird news around the world]
- [http://www.birdforum.net/ BirdForum] Category:Chordates
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Tinamiformes

Tinamus
Nothocercus
Crypturellus
Rhynchotus
Nothoprocta
Nothura
Taoniscus
Eudromia
Tinamotis The tinamous are one of the most ancient groups of bird, members of a South American bird family of about 47 species in 9 genera. Although they look similar to other ground-dwelling birds like quail and grouse, they have no close relatives and are classified as a single family Tinamidae within their own order, the Tinamiformes. Of Gondwanan origin, they are distantly related to the ratites, the order Struthioniiformes that includes the rheas, Emu, and kiwi. Although the fossil record in South America is generally poor (or perhaps largely undiscovered as yet), the known tinamou fossil record goes back 10 million years. Together with the ratites, they make up the Paleognathae, or “Old Jaws”, as distinct from the vast majority of modern birds in the Neognathae , or “New Jaws”. There are 47 species of tinamou in South America and north to Mexico, occurring in a wide range of habitats. They eat a variety of food including insects and berries. Tinamou are rarely seen. Most inhabit the tropical lowlands of South America, typically in dark, dense forest, but some species range as far north as Mexico and occur in a wide range of habitats. They eat a variety of food including insects and berries. Although some species are quite common, they are very secretive. A small number of species live in more open, grassy country, but even these are wary. Tinamous lay several eggs which are attractively coloured and have a hard gloss like porcelain. The young are precocial, and can run almost as soon as they hatch. Species are:
- Order Tinamiformes
- Family Tinamidae
- White-throated Tinamou, Tinamus guttatus
- Grey Tinamou, Tinamus tao
- Solitary Tinamou, Tinamus solitarius
- Black Tinamou, Tinamus osgoodi
- Great Tinamou, Tinamus major
- Highland Tinamou, Nothocercus bonapartei
- Tawny-breasted Tinamou, Nothocercus julius
- Hooded Tinamou, Nothocercus nigrocapillus
- Berlepsch's Tinamou, Crypturellus berlepschi
- Little Tinamou, Crypturellus soui
- Cinereous Tinamou, Crypturellus cinereus
- Tepui Tinamou, Crypturellus ptaritepui
- Brown Tinamou, Crypturellus obsoletus
- Undulated Tinamou, Crypturellus undulatus
- Pale-browed Tinamou, Crypturellus transfasciatus
- Brazilian Tinamou, Crypturellus strigulosus
- Grey-legged Tinamou, Crypturellus duidae
- Red-legged Tinamou, Crypturellus erythropus
- Magdalena Tinamou, Crypturellus erythropus saltuarius
- Yellow-legged Tinamou, Crypturellus noctivagus
- Black-capped Tinamou, Crypturellus atrocapillus
- Thicket Tinamou, Crypturellus cinnamomeus
- Slaty-breasted Tinamou, Crypturellus boucardi
- Choco Tinamou, Crypturellus kerriae
- Variegated Tinamou, Crypturellus variegatus
- Rusty Tinamou, Crypturellus brevirostris
- Bartlett's Tinamou, Crypturellus bartletti
- Small-billed Tinamou, Crypturellus parvirostris
- Barred Tinamou, Crypturellus casiquiare
- Tataupa Tinamou, Crypturellus tataupa
- Red-winged Tinamou, Rhynchotus rufescens
- Taczanowski's Tinamou, Nothoprocta taczanowskii
- Kalinowski's Tinamou, Nothoprocta kalinowskii
- Ornate Tinam