Non-Vertebrates Period 5 Umer Khan James Trimble

General Characteristics  Small filter-feeders  Lack big brains and enhanced sensory structures  Has a set of characters that unifies the phylum: a notochord A perforated pharynx (gill silts) A dorsal nerve cord A post anal-tail

Classes within the phylum  There are two subphyla: represented by Tunicatesrepresented by Lancelets pload.wikimedia.org/wikipedia/commons/thumb/ a/a0/Branchiostoma_lanceolatum.png/250px- Branchiostoma_lanceolatum.png 1. Urochordata2.Cephalocordata

Body Plan: Tunicates

Body Plan: Lancelets

Feeding: Tunicates  Suspension feeders  Two openings in their body cavity: In-current – intake food and water Ex-current – expels waste and water  Feed by filtering sea water through pharyngeal slits  Primary food source is plankton  Pharynx is covered by ciliated cells which allow consumed plankton to pass through the esophagus.

Feeding: Lancelets  Suspension feeders  Water passes from the mouth into the large pharynx Lined by gill-slits  The ventral surface of pharynx contains the endostyle Endosytle produces a film of mucus  Ciliary action pushes the mucus in a film over the surface to the gill slits, trapping suspended food particles as it does so.

Respiration Lancelets  Have no respiratory system  Breathe solely through their skin Skin consists of a simple epithelium  Little respiration occurs in the gill slits Silts are primarily devoted to feeding Tunicates  Gas exchange occurs across the gill and also across the lining of the atrium

Circulation Lancelets  The circulatory system does resemble that of primitive fish in its general layout, but is much simpler, and does not include a heart.  There are no blood cells  No hemoglobin Tunicates  Controlled by blood vessels that circulate through the exoskeleton

Excretion Lancelets  The excretory system consists of segmented “kidneys” containing protonephridia instead of nephrons  There are numerous, segmented gonads Tunicates  Wastes are excreted through the intestine The intestine ends as an anus in the atrium below the atrial aperture

Response Lancelets & Tunicates  Have a dorsal nerve cord not protected by bone Protected by notochord  Do not posses a true brain  No complex sense organs comparable to those of vertebrates

Movement Lancelets  Have a translucent, fish-like body, but without any paired fins or other limbs  Poorly developed tail fin Are not efficient swimmers  Do posses some cartilage but no true skeleton for movement Tunicates  Movement is controlled by the cerebral ganglion Movement is equivalent to the human brain

Reproduction Lancelets  Have separate sexes  Equal numbers of males and females  Egg and sperm are released into the water The fertilized eggs develop into larvae Tunicates  Reproduce asexually and sexually  Reproduce by budding  Have one testes and the ovary organ inside the body  Fertilization takes place outside and eggs are produced inside

WORKS CITED  Bassham, Susie. "Chordates." N.p., Web. 20 Apr  Holland, L.Z. "Early Development in the Lancelets." The Biological Bulletin. Marine Biological Laboratory, Web. 20 Apr  "Lancelets: Cephalochordata." Animals Jrank. Net Industries, Web. 20 Apr