Vertebrates

University:
Dakota State University
Course:
BIOL 365 | Vertebrate Zoology
Academic year:

2022
Views:

205

Pages:

13
Author:

gewoekerdodx

VERTEBRATES Chordates ◦Any of a phylum (Chordata) of animals having at least at some stage of development a notochord, dorsally situated central nervous system, and gill slits and including the vertebrates, lancelets, and tunicates. What is a Chordate? • All chordates have 4 basic features that are present at some point during their life cycle • Hollow Nerve Cord – Nerve cord in which nerves branch out at regular intervals • Notochord – Long supporting rod that runs throughout body • Pharyngeal Pouches – Paired structures in throat • Muscular Tail – Extends beyond anus • Only 4-5% of animals are chordates • Examples = Fish, Amphibians, Reptiles, Birds Chordate Cladograms ◦A cladogram is a type of diagram that shows hypothetical relationships between groups of organisms. A cladogram resembles a tree, with branches off a main trunk. Key aspects of a cladogram are the root, clades, and nodes. The root is initial ancestor that is common to all groups branching off. How can we “classify” items on a Cladogram? ◦Whether the animal has: ◦Hair/Fur ◦Jaw/Jawless ◦Bilateral Symmetry ◦Lungs/Gills ◦Claws/Nails ◦Gives birth/Lays eggs ◦Lives in Water/On Land Chordate Cladogram Fishes Nonvertebrate chordates Invertebrate ancestor Amphibians Reptiles Birds Mammals The Generalized Structure of a Chordate Section 30-1 Notochord Muscle segments Tail Anus Hollow nerve cord Mouth Pharyngeal pouches All vertebrates share common features. • An endoskeleton allows vertebrates to grow to large sizes. •Internal Skeleton •Made of bone or cartilage • An endoskeleton can be divided into four parts. braincase – braincase (cranium) – vertebrae – bones – gill arches (in fish and some amphibians) vertebrae bones • There are seven classes of vertebrates. – Agnatha are jawless fish. – Cartilaginous and bony fish are characterized by the presence of jaws. – Amphibians are characterized by the presence of four limbs. – Reptiles, birds, and mammals are characterized by the presence of an amnion. – Birds are characterized by the presence of feathers. – Mammals are characterized by the presence of hair. JAWS Jaws helped vertebrates to become successful predators. VERTEBRAE Vertebrates have a segmented backbone. Amphibia Mammalia birds mammals Aves amphibians Osteichthyes bony fish Chondrichthyes cartilaginous fish lamprey Agnatha FOUR LIMBS Four limbs let animals move from the water to life on land. FEATHERS Feathers insulate birds from the cold and allow for flight. HAIR Hair helps mammals to maintain constant body temperatures by roviding insulation from the cold.

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