Harlingen South High School Biology

The world consist of animals with a backbone and animals that lack one. Vertebrate are animals that contain a backbone and make up about 2% of the animal world. Invertebrates animals that lack a backbone make up 98% of the animal world.

Phylum Porifera (Sponges) 1)No definite symmetry. 2)Body multicellular, few tissue, no organs. 3)Cells and tissues surround a water filled space but there is no true body cavity. 4)All are sessile, (live attached to something as an adult). 5)Reproduce sexually or asexually, sexual reproduction can be either gonochoristic or hermaphroditic. 6)Has no nervous system. 7)Has a distinct larval stage which is planktonic. 8)Lives in aquatic environments, mostly marine. 9)All are filter feeders. 10)Often have a skeleton of spicules.

The Phylum Echinodermata 1)Possess 5-rayed symmetry, mostly radial, sometimes bilateral. 2)Body has more than two cell layers, tissues and organs. 3)Body cavity a true coelom. 4)Most possesses a through gut with an anus. 5)Body shape highly variable, but with no head. 6)Nervous system includes a circum-oesophageal ring. 7)Has a poorly defined open circulatory system. 8)Possesses a water vascular system, which hydraulically operates the tube feet or feeding tentacles. 9)Without excretory organs. 10)Reproduction normally sexual and gonochoristic. 11)Feeds on fine particles in the water, detritus or other animals. 12)All live marine environments.

The Phylum Cnidaria 1)Radially Symmetrical. 2)Body multicellular, few tissues, some organelles. 3)Body contains an internal cavity and a mouth. 4)Two different forms exist, medusa and polyp 5)Reproduction is asexual or sexual. 6)Has a simple net like nervous system. 7)Has a distinct larval stage which is planktonic. 8)Lives in aquatic environments, mostly marine. 9)Mostly carnivorous otherwise filter feeders. 10)May have a minimal skeleton of chitin or calcium carbonate.

The Phylum Platyhelminthes 1)Bilaterally symmetrical. 2)Body having 3 layers of tissues with organs and organelles. 3)Body contains no internal cavity. 4)Possesses a blind gut (i.e. it has a mouth but no anus) 5)Has Protonephridial excretory organs instead of an anus. 6)Has normally a nervous system of longitudinal fibres rather than a net. 7)Generally dorsoventrally flattened. 8)Reproduction mostly sexual as hermaphrodites. 9)Mostly they feed on animals and other smaller life forms. 10)Some species occur in all major habitats, including many as parasites of other animals.

The Phylum Nematoda 1)Bilaterally symmetrical, and vermiform (wormlike). 2)Body has more than two cell layers, tissues and organs. 3)Body cavity is a pseudocoel, body fluid under high pressure. 4)Body possesses a through gut with a subterminal anus. 5)Body covered in a complex cuticle. 6)Has a nervous system with pharyngeal nerve ring. 7)Has no circulatory system (no blood system) 8)Reproduction normally sexual and gonochoristic. 9)Feed on just about everything. 10)Live just about everywhere, many species are endoparasites.

The Phylum Annelida 1)Bilaterally symmetrical and vermiform. 2)Body has more than two cell layers, tissues and organs. 3)Body cavity is a true coelom, often divided by internal septa. 4)Body possesses a through gut with mouth and anus. 5)Body possesses 3 separate sections, a prosomium, a trunk and a pygidium. 6)Has a nervous system with an anterior nerve ring, ganglia and a ventral nerve chord. 7)Has a true closed circulatory system. 8)Has no true respiratory organs. 9)Reproduction normally sexual and gonochoristic or hermaphoditic. 10)Feed a wide range of material. 11)Live in most environments.

The Phylum Arthropoda 1)Bilaterally symmetrical (in most cases). 2)Body has more than two cell layers, tissues and organs. 3)Body cavity a true coelom. 4)Most possesses a through straight gut with an anus (in most cases). 5)Body possesses 3 to 400+ pairs of jointed legs. 6)Body possesses an external skeleton (in most cases). 7)Body is divided in 2 or 3 sections. 8)Nervous system includes a brain and ganglia. 9)Possesses a respiratory system in the form of tracheae and spiracles (in most cases). 10)Possesses a open or lacunnar circulatory system with a simple heart, one or more arteries, and no veins, (in most cases). 11)Reproduction normally sexual and gonochoristic, but can be parthenogenetic. 12)Feed on everything. 13)Live everywhere.

The Phylum Mollusca 1)Bilaterally symmetrical. 2)Body has more than two cell layers, tissues and organs. 3)Body without cavity. 4)Body possesses a through gut with mouth and anus. 5)Body monomeric and highly variable in form, may possess a dorsal or lateral shells of protein and calcareous spicules. 6)Has a nervous system with a circum-oesophagal ring, ganglia and paired nerve chords. 7)Has an open circulatory system with a heart and an aorta. 8)Has gaseous exchange organs called ctenidial gills. 9)Has a pair of kidneys. 10)Reproduction normally sexual and gonochoristic. 11)Feed a wide range of material. 12)Live in most environments.

The Phylum Chordata 1.They have bilateral symmetry. 2.Chordata have segmented bodies, which include segmented muscles. 3.Chordata have a well-developed coelem. 4.They have a hollow never cord that usually ends with a brain. 5.Chordata have a post anal tail at some point in their life. 6.They have pharyngeal or gill slits at some points in their life. 7.Chordata have a ventral heart, with blood vessels and a closed circulatory system 8.They have complete digestive system, meaning that they have a different anus and mouth. 9.They have an endoskeleton made out of either bone or cartalige.