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#1
Tuesday, February 12, 2008
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Phylum
Phylum
In biological taxonomy, a 'phylum' (plural: phyla) is a taxonomic rank at the level below kingdom and above class. "Phylum" is adopted from the Greek phylai, the clan-based voting groups in Greek city-states. Phyla represent the largest generally accepted groupings of animals and other living things with certain evolutionary traits, although the phyla themselves may sometimes be grouped into superphyla (e.g. Ecdysozoa with eight phyla, including arthropods and roundworms; and Deuterostomia with the echinoderms, chordates, hemichordates and arrow worms). Informally, phyla can be thought of as grouping animals based on general body plan; this is morphological grouping. Thus despite the seemingly different external appearances of organisms, they are classified into phyla based on their internal organizations. For example, though seemingly divergent, spiders and crabs both belong to Arthropoda, whereas earthworms and tapeworms, similar in shape, are from Annelida and Platyhelminthes, respectively. Although the International Code of Botanical Nomenclature allows the use of the term "Phylum" in reference to plants, the term "Division" is almost always used by botanists. The best known animal phyla are the Mollusca, Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Echinodermata, and Chordata, the phylum to which humans belong. Although there are approximately 35 phyla, these nine include the majority of the species. Many phyla are exclusively marine, and only one phylum is entirely absent from the world's oceans: the Onychophora or velvet worms. The most recently discovered phylum is Cycliophora found in 1993; only three phyla were discovered in the last century. The Cambrian explosion was a great flowering of life forms that occurred between roughly 530 and 520 million years ago;during this time organisms similar to, but not strictly members of, modern phyla existed;whilst some appear to be represented in the Ediacaran biota, it remains a matter of debate whether all phyla existed prior to the explosion. Over time the roles among different phyla have varied. For instance, during the Cambrian, the dominant megafauna, or large animals, were arthropods, whereas now the megafauna is dominated by vertebrates (chordata).The arthropods are still by far the most dominant phylum. List of animal phyla Phylum Meaning Group Distinguishing characteristics Species described Acanthocephala Thorny head Thorny-headed worms Reversible spiny proboscis about 750 Acoelomorpha Without gut Acoels No mouth or alimentary canal Annelida Little ring Segmented worms Multiple circular segments about 15,300 modern Arthropoda Jointed foot Arthropods Chitin exoskeleton 1,134,000+ Brachiopoda Arm foot Lamp shells Lophophore and pedicle between 300 and 500 extant Bryozoa Moss animals Moss animals, sea mats Lophophore, no pedicle, ciliated tentacles about 5,000 living species Chaetognatha Longhair jaw Arrow worms Chitinous spines either side of head, fins about 100 modern species Chordata Cord Chordates Hollow dorsal nervous chord about 100,000+ Cnidaria Stinging nettle Coelenterates Nematocysts (stinging cells) about 11,000 Ctenophora Comb bearer Comb jellies Eight "comb rows" of fused cilia about 100 modern species Cycliophora Wheel carrying Symbion Circular mouth surrounded by small cilia at least 3 Echinodermata Spiny skin Echinoderms Five-fold radial symmetry, mesodermal calcified spines about 7,000 living species and 13,000 extinct ones Echiurai Spine tail Spoon worms Set of hooks at posterior end about 140 Entoprocta Inside anus Goblet worm Anus inside ring of cilia about 150 Gastrotricha Hair stomach Meiofaunai Two terminal adhesive tubes about 690 Gnathostomulida Jaw orifice Jaw worms about 100 Hemichordata Half cord Acorn worms Stomochord in collar about 100 living species Kinorhyncha Motion snout Mud dragons Eleven segments, each with a dorsal plate about 150 Loricifera Corset bearer Brush heads Umbrella-like scales at each end about 122 Mesozoa Middle animals Mesozoans Somatoderm of ciliated cells surrounding reproductive cell(s) Micrognathozoa Tiny jaw animals — Accordion like extensible thorax 1 Mollusca Thin shell Mollusks / molluscs Muscular foot and mantle round shell 112,000[7] Myxozoa Slime animals Polar capsules resembling nematocysts 13,000+ Nematoda Thread like Round worms Round cross section, keratin cuticle 80 000 – 1 million Nematomorpha Thread form Horsehair worms about 320 Nemertea A sea nymph Ribbon worms about 1200 Onychophora Claw bearer Velvet worms Legs tipped by chitinous claws about 200 modern Orthonectida Straight swim about 20 Phoronida Zeus' mistress Horseshoe worms U-shaped gut 20 Placozoa Plate animals 1 Platyhelminthes Flat worms Flat worms about 25,000[8] Porifera Pore bearer Sponges Perforated interior wall over 5,000 modern Priapulida Penis Priapulid worms Retractable proboscis surrounded by papillae 17 Rhombozoa Lozenge animal — Single axial cell surrounded by ciliated cells 75 Rotifera Wheel bearer Rotifers Anterior crown of cilia about 2000 Sipuncula Small tube Peanut worms Mouth surrounded by invertible tentacles 144–320 Tardigrada Slow step Water bears Four segmented body and head 1,000+ Xenoturbellida Strange flatworm — Ciliated deuterostome 2 TOTAL 2,000,000- Groups formerly ranked as phyla Name as phylum Common name Current consensus Craniata — Subgroup of phylum Chordata; perhaps synonymous with Vertebrata. Cephalochordata Lancelets Subphylum of phylum Chordata Cephalorhyncha — Superphylum Scalidophora. Enterepneusta Acorn worms Class of phylum Hemichordata. Pentastomida Tongue worms Subclass of Maxillopoda of phylum Arthropoda. Pogonophora Beard worms Part of family Siboglinidae of phylum Annelida. Pterobranchia — Class of phylum Hemichordata. Symplasma Glass sponges Class Hexactinellida of phylum Porifera. Urochordata Tunicates Subphylum of phylum Chordata. Vestimentifera Vent worms Part of family Siboglinidae of phylum Annelida. List of plant divisions Division Meaning Common name Distinguishing characteristics Anthocerotophyta Flower-horn plants Hornworts Horn-shaped sporophytes, no vascular system Bryophyta Moss plants Mosses Persistent unbranched sporophytes, no vascular system Marchantiophyta Marchantia plants Liverworts Ephemeral unbranched sporophytes, no vascular system Lycopodiophyta Wolf foot plants Clubmosses & Spikemosses Microphyll leaves, vascular system Pteridophyta Fern plants Ferns & Horsetails Prothallus gametophytes, vascular system Pteridospermatophyta Fern with seeds plant Seed ferns Only known from fossils, mostly Devonian, ranking in dispute[9] Pinophyta Sap/pitch plants Conifers Cones containing seeds Cycadophyta Palm plants Cycads Seeds, crown of compound leaves Ginkgophyta Ginkgo plants Ginkgo, Maidenhair Seeds not protected by fruit (single species) Gnetophyta Gnetophytes Seeds and woody vascular system Anthophyta Flower plant Flowering plants Producing flowers and fruit (or close relatives) List of fungi divisions Phylum Meaning Common name Distinguishing characteristics Chytridiomycota Little pot mushroom Chytrids Cellulose in cell walls, flagellated gametes Deuteromycota Second mushroom Imperfect fungi Only reproduce asexually Zygomycota Yoke mushroom Zygomycetes Blend gametangia to form a zygosporangium Glomeromycota Ball mushroom None Form arbuscular mycorrhizae with plants Ascomycota Bag/Wineskin Mushroom Sac fungi Produce spores in an 'ascus' Basidiomycota Basidium Mushroom None Produce spores from a 'basidium'
__________________
"A man can be as great as he wants to be. If you believe in yourself and have the courage, the determination, the dedication, the competitive drive and if you are willing to sacrifice the little things in life and pay the price for the things that are worthwhile, it can be done." 
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#2
Saturday, April 05, 2008
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@Mr Omer!!
would u like to mention the source from where u have collected this information.......... according to my view u have mentioned all these things in a very complicated way with no sequence.........try to make it simple for others regards
__________________
~Miss zoologist~
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#3
Sunday, April 06, 2008
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Well i agree with u but the format in which the text is posted in the forum threads makes the postings complicated. I myself was astonished to c wen i posted the contents here. I have also raised the issue that we must be given a suitable format to add tables to our posts.
Anyway............ its quite complicated and even i can't get it through. Here is the source: http://en.wikipedia.org/wiki/Phylum Regards
__________________
"A man can be as great as he wants to be. If you believe in yourself and have the courage, the determination, the dedication, the competitive drive and if you are willing to sacrifice the little things in life and pay the price for the things that are worthwhile, it can be done."
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#4
Friday, April 11, 2008
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ok
but let me tell u.....it will be much better to follow the books for the classification and related texon.....the number of things u have mentioned are far apart from what is required for CSS exam....especially while discussing animal phyla........we should follow the standard form.......otherwise there will be confusion regards
__________________
~Miss zoologist~
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| The Following User Says Thank You to prissygirl For This Useful Post: | ||
Omer (Friday, April 11, 2008) | ||
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