Chordate Characteristics Advanced Life Science Rainier Jr/Sr High School Mr. Taylor

Chordate Characteristics Phylum Chordata A phylum of the Animal Kingdom All the groups we have studied were also phyla of the Kingdom Animalia: Porifera Coelenterata Mollusca Platyhelminthes, Nematoda, & Annelida Echinodermata Arthropoda

Chordate Characteristics Phylum Chordata Members of the phylum Chordata must have at some time in their life the following 4 characteristics: A notocord A stiff cartilaginous rod in their dorsal region Becomes the backbone/vertebrae in those animals that have a backbone

Chordate Characteristics Phylum Chordata Members of the phylum Chordata must have at some time in their life the following 4 characteristics: A dorsal hollow nerve cord Becomes the spinal cord in almost all chordates

Chordate Characteristics Phylum Chordata Members of the phylum Chordata must have at some time in their life the following 4 characteristics: Pharyngeal gill slits Become gills and their supporting structures in fish and amphibians Are modified into other structures in most organisms, including fish and amphibians most notably they become jaws

Chordate Characteristics Phylum Chordata Members of the phylum Chordata must have at some time in their life the following 4 characteristics: A muscular post-anal tail Persists in many chordates, is re-absorbed in others

Chordate Characteristics Phylum Chordata Members of the phylum See also Figure 25.1, page 758

Chordate Characteristics Phylum Chordata 3 Subphyla Two subphyla do NOT have backbones or vertebrae. Urochordata (tunicates) Cephalochordata (lancelets) One Subphyla has backbones or vertebrae Vertebrata

Chordate Characteristics Phylum Chordata Subphylum Vertebrata These animals DO have backbones or vertebrae Have a bony or cartilaginous endoskeleton Axial skeleton: skull + vertebrae or backbone + ribs Appendicular skeleton: pectoral and pelvic girdles + limbs Possess distinct cephalization Have a closed circulatory system and a true coelom Most eliminate nitrogenous wastes via kidneys Most have two sets of paired appendages

Subphylum Vertebrata Phylum Chordata Subphylum Vertebrata Made up of numerous Classes Most primitive class is Agnatha (“without jaws”) 2 groups: lampreys and hagfish Lampreys Have long, thin bodies with cartilage skeletons Heart has 2 chambers Atrium (accepts blood) Ventricle (pumps blood) Notocord persists throughout life

Subphylum Vertebrata Phylum Chordata Subphylum Vertebrata Made up of numerous Classes Most primitive class is Agnatha (“without jaws”) 2 groups: lampreys and hagfish Lampreys Most are parasitic Reproduce by laying eggs (oviparous) External fertilization Well-developed eyes

Subphylum Vertebrata Phylum Chordata Subphylum Vertebrata Made up of numerous Classes Most primitive class is Agnatha (“without jaws”) 2 groups: lampreys and hagfish Hagfish Long, thin bodies, cartilage skeleton Are scavengers, reside on the ocean floor Only have eye slits Poor sensory receptors except for chemosensors Secrete LOTS of mucus (slime) to keep away predators.

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