Kingdom Animalia

Kingdom Animalia By: Ernesto Marin & Axel Miranda

Porifera • Porifera is a phylum of aquatic invertebrate animals that comprises the sponges • Sponges are animals of the phylum Porifera (Pore bearer). Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells • Has no tissues, no symmetry, no body cavity, no circulatory system, no nervous system; Aquatic filter feeders, and specialized cell types

Stromatoporoida • Stromatoporoids are an extinct, sessile, coral-like marine organism of uncertain relationship that built up calcareous masses composed of laminae and pillars, occurring from the Cambrian to the Cretaceous • Stromatoporoids are an order of colonial aquatic invertebrates • These invertebrates were important reef-formers throughout the Paleozoic and the Late Mesozoic • The group was previously thought to be related to the corals and placed in the Phylum Cnidaria • Stromatoporoids are useful markers whose form and occurrence can diagnose the depositional environment of sedimentary strata

Calcarea • Members of the group Calcarea, are the only sponges that posses spicules composed of calcium carbonate • The spicules do not have hollow axial canals • The Calcarea first appears at the base of the Lower Cambrian and has persisted until the present • Greater than 100 fossil genera are known • The calcarean sponges were at their most diverse during the Cretaceous • Now a days, their diversity is greater in the tropics, as is the case with most marine groups • They are found in shallow waters, though at least one species is known from a depth of 4,000 meters

Hexactinellida • The Hexactinellids, or glass sponges, are characterized by siliceous spicules consisting of six rays intersecting at right angles • Hexactinellids are widely viewed as an early branch within the Porifera because there are major differences between extant hexactinellids and other sponges • Much of their tissues are syncitia, extensive regions of multinucleate cytoplasm • Some discrete cell types do exist, including archaeocytes • Hexactinellids do not posses the ability to contract; whereas, other sponges do • They posses a unique system for rapidly conducting electrical impulses across their bodies, thus allowing them to react quickly to external stimuli

Demospongea • Demospongea are by far the most diverse sponge group • Greater than 90% of the 5,000 known living sponge species are demosponges • The vast majority of living demosponges do not posses skeletons that would easily fossilize, thus their fossil diversity, which peaks in the Cretaceous • Demosponge skeletons are composed of spongin fibers and, or siliceous spicules • Demospnges take on a variety of growth forms from encrusting sheets living beneath stones to branching stalks upright in the water column • They tend to be large and only exhibit the leucon grade of organization

Cnidaria • Cnidaria is a phylum of aquatic invertebrate animals that comprises the coelenterates • Contains over 9,000 species of animals found exclusively in aquatic and mostly marine environments • Their distinguishing feature is cnidocytes, specialized cell that they use mainly for capturing prey • They are also called Coelenterata • They are of a phylum of predominately marine animals with a sac-like body and stinging cells on tentacles that surround a single opening to the gut cavity • The two basic body forms are the medusa and the polyp

Hydrozoa • Hydrozoa is a class of coelenterates that includes hydras and “Portuguese men-of-war” • Many of them are colonial and some kinds have both polypoid and medusoid phases • Hydra never goes through a medusoid stage and spends its entire life as a polyp • Hydra is not typically of the Hydrozoa as a whole • Most hydrozoans alternate between a polyp and a medusa stage-they spend part of their lives as “jellyfish” which are hard to distinguish from scyphozoan jellyfish

Anthozoa • Anthozoans are probably the most famous cnidarians: they include the corals that build great reefs in tropical waters, as well as sea anemones, sea fans, and sea pens • They also have a long and diverse fossil record, dating back at least 550 million years ago • The oldest anthozoans are probably some of the polyp-like and sea pen-like fossils from the Vendian(late Precambrian) • A few tens of millions of years later, in the Cambrian period, the first mineralized coral-like organisms appeared • True corals of the kind living today did not appear until the middle Triassic, at about the same time that the first dinosaurs were evolving

Scyphozoa • The “true jellyfish” • Scyphozoans include most of the jellyfish familiar to beach-goers; other similar organisms are classified in the Hydrozoa and Cubozoa, two other groups of cnidarians • True jellyfish are graceful and sometimes deadly creatures • Their stings may cause skin rashes, muscle cramps, and even death • Jellyfish range in size from a mere twelve millimeters to more than two meters across • The largest is Cyanea artica, which may have tentacles over 40 meter long! • Jellyfish have no head, no skeleton, and no special organs for respiration or excretion

Ctenophora • Ctenophores have eight “comb rows” of fused cilia arranged along the sides of the animal • These cilia beat synchronously and propel ctenophores through the water • Some species move with a flapping motion of their lobes or undulations of the body • Many ctenophores have two long tentacles, but some lack tentacles completely

Comb Jelly • Comb Jellies can occur in huge numbers and are know to effect fisheries at times because of their feeding on the eggs and fry • Mnemiopsis leidyi is common on the Atlantic coast of North America, where it normally feeds on copepods and the larval forms of various other marine animals • These other species include the larvae of Oysters and it sometimes accumulates in such vast numbers that it has a negative effect on the Oyster crop • More interestingly, it was accidentally introduced into the Black Sea in the early 1980s where it experienced a massive population explosion which had disastrous effects on the Black Sea fishing industry

Platyhelminthes • Platyhelminthes are the simplest animals that are bilaterally symmetrical and triploblastic composed of three fundamental cell layers are the Platyhelminthes and flatworms • Flatworms have no body cavity other than the gut and lack an anus; the same pharyngeal opening both takes in food and expels wastes • In larger flatworms, the gut is often very highly branched in order to transport food to all parts of the body • The lack of a cavity also constrains flatworms to be flat; they must respire by diffusion, and no cell can be too far from the outside, making a flattened shape necessary

Turbellaria • Turbellarians are free-living flatworms • Free-living means they are not parasites • Turbellarians have three tissue layers and bilateral symmetry • These animals have a complex , but incomplete digestive tract, meaning they have no anus and all waste leaves the body through the mouth • Turbellarians have a brain and nerve cords that form a ladder-like nervous system • They have numerous sense organs at the front end of the body and touch receptors all over the body and have organs for eliminating waste and controlling the salt balance in their cells

Trematoda • Trematoda is a class within the phylum Platyhelminthes that contains two groups of parasitic flatworms, commonly referred to as “flukes” • The trematodes or flukes are estimated to include 18,000 to 24,000 species, and are divided into two subclasses • Nearly all trematodes are parasites of mollusks and vertebrates • Trematodes are flattened oval or worm-like animals, usually no more than a few centimeters in length

Monogenea • The class Monogenea is distinguished by most of its members being ectoparasite • Digeneans and Cestodes are all endoparasites • In order to facilitate their parasitic life style the Monogeneans have complicated attachment organs at the posterior or tail end of their bodies • Often include a mixture of suckers, clamps, hooks and spines • Those few species, which are endoparasites, do not normally venture deeply into their host’s tissues, but live instead in the cloaca or bladder • Monogeneans have an indirect life cycle, meaning that always have more than one host species and the animal lives in separate host during different stages of its life

Cestoda • Cestodes, also known as tapeworms, are the most specialized of the Platyhelminthes parasites • All Cestodes have at least one, and sometimes more than one, secondary or intermediate host as well as their primary host • The primary host is normally a vertebrate • In some cases both hosts are vertebrates • In a few species their may be only a single host • A number of tapeworms include mankind in their life cycles, but infection is not normally a serious health problem and can be cured • There are more than 1,000 species of tapeworms known to science, and nearly every species of vertebrate is liable to infection from at least one species of tapeworm

Rotifera • Rotifers are microscopic aquatic animals of the phylum Rotifera • Rotifers can be found in many freshwater environments and in moist soil • The habitat of Rotifers may include still water environments, such as lake bottoms, as well as flowing water environments, such as rivers and streams • Rotifers are also commonly found on mosses and lichens growing on tree trunks and rocks, in rain gutters and puddles, in soil or leaf litter, on mushrooms growing near dead trees, in tanks of sewage treatment plants, and even on freshwater crustaceans and aquatic insect larvae • Because of their very small size and mostly soft bodies, Rotifers are not commonly favored for fossilization

Monogononta • A class of the phylum Rotifera characterized by a single gonad and mixed sexual and asexual reproduction • Monogonont rotifers are a major invertebrate component of freshwater and coastal marine ecosystems as judged by biomass, ecological importance, and number of species • Some species of Brachionus are grown commercially at rates of more than 100,000 per day as food for aquaculture of larval marine finfish and crustaceans

Bdelloidea • Bdelloidea is a class of rotifers found in fresh water and moist soil • Bdelloids typically have a well-developed corona, divided into two parts, on a retractable head • They may move by swimming or crawling • The latter commonly involves taking alternate steps with the head and tail, as do certain leeches, which gives the group their name (Bdella, meaning leech) • Bdelloids have been of interest to those interested in the evolutionary role of sexual reproduction, because it has disappeared entirely from the group: males are not present within the species, and females reproduce exclusively by parthenogenesis

Seisonidea • Rotifers in the class Seisonidea are epizoic, living on the gills of marine crustaceans • Only two species are known to exist • Whether they’re parasites or simply living on the crustaceans is unclear • Seisonid rotifers have slightly more complicated reproductive cycles than do Bdelloids, since both males and females are present and reproduction is always sexual • Seisonids are unique in that they’re the only rotifers that always reproduce sexually • Male and female Seisonids are more or less identical in size and shape • A female has two ovaries, but no yolk glands, and a male has a pair of testes

Mollusca • The mollusks constitute one of the largest phyla of animals, both in numbers of living species and in numbers of individuals • A significant characteristic of mollusks is their possession of a coelom, a fluid-filled cavity that develops within the mesoderm • The coelom not only functions as a hydrostatic skeleton, but also provides pace within which the internal organs can be suspended by the mesenteries • All mollusks have a soft body, which is generally protected by a hard, calcium-containing shell • In some forms however, the shell has been lost in the course of evolution, as in slugs and octopuses, or greatly reduced in size and internalized, as in squids • Structurally, mollusks are quite distinct from all other animals • However, all modern mollusks have the same fundamental body plan

Bivalvia • Bivalvia, commonly called the bivalves, is a taxonomic class of marine and freshwater mollusks that have a laterally compressed body enclosed by a shell in two hinged parts • This class includes the clams, oysters, mussels, scallops and numerous other families • The majority are filter feeders and have no head or radula • The gills have been modified into ctenidia, specialized organs for feeding and breathing • The majority of bivalves are infaunal and bury themselves to hard surfaces • A few bore into wood, clay or rock and live inside these substances

Gastropoda • Gastropods are one of the most diverse groups of animals, both in form, habit, and habitat • They are by far the largest group of mollusks, with more than 62,000 described living species, and they comprise about 80% of living mollusks • Estimates of total extant species range from 40,000 to over 100,000, but there may be as many as 150,000 species • There are about 13,000 named genera for both recent and fossil gasthropods • They have a long and rich fossil record from the Early Cambrian that shows periodic extinctions of subclades, followed by diversification of new groups

Cephalopoda • Cephalopods are the most intelligent, most mobile, and the largest of all mollusks • Squid, octopuses, cuttlefish, the chambered nautilus, and their relatives display remarkable diversity in size and lifestyle with adaptations for predation, locomotion, disguise, and communication • These “brainy” invertebrates have evolved suckered tentacles, camera-like eyes, color-changing skin, and complex learning behavior • Their lengthy evolutionary history spans and impressive 500 million years and the abundant fossils they’ve left behind (mostly shelled nautiloids and ammonoids) record repeated speciation and extinction events

References • Book • http://www.google.com/#hl=en&safe=off&q=Porifera&tbs=dfn:1&tbo=u&sa=X&ei=2mrOT_KLJoGi2gXB68TVDA&sqi=2&ved=0CGAQkQ4&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=7ffac515254ada2f&biw=1920&bih=979 • http://www.google.com/#hl=en&safe=off&sa=X&q=stromatoporoids&tbs=dfn:1&tbo=u&ei=Wm3OT5XjMMGC2AXwg5HcDA&ved=0CEwQkQ4&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=7ffac515254ada2f&biw=902&http://www.google.com/#hl=en&safe=off&sa=X&q=stromatoporoids&tbs=dfn:1&tbo=u&ei=Wm3OT5XjMMGC2AXwg5HcDA&ved=0CEwQkQ4&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=7ffac515254ada2f&biw=902&bih=951bih=951 • http://www.ucmp.berkeley.edu/porifera/calcarea.html • http://www.ucmp.berkeley.edu/porifera/hexactinellida.html • http://www.ucmp.berkeley.edu/porifera/demospongia.html • http://www.ucmp.berkeley.edu/cnidaria/hydrozoa.html • http://www.ucmp.berkeley.edu/cnidaria/anthozoa.html • http://www.ucmp.berkeley.edu/cnidaria/scyphozoa.html • http://www.earthlife.net/inverts/ctenophora.html • http://en.wikipedia.org/wiki/Trematoda • http://www.earthlife.net/inverts/monogenea.htmlhttp://www.earthlife.net/inverts/cestoda.html • http://en.wikipedia.org/wiki/Bdelloidea • http://en.wikipedia.org/wiki/Bivalvia

Kingdom Animalia