The Vertebrates Packet #78 Chapter #34
Introduction • All vertebrates are • Found within Phylum Chordata; Subphylum Vertebrata • Deuterostomes • Coelomates • Bilateral symmetrical • Have an endoskeleton • Have a closed circulatory system • Have a ventral heart
Introduction II • During the lifespan of chordates, they have a notochord which serves as a flexible supporting rod. • Chordates have a single dorsal tubular(hollow) nerve cord. • All chordates have pharyngeal gill silts • In some species, the gill slits are only found in the embryos • MOST chordates have a muscular postanal tail.
Invertebrates vs. Vertebrates • How are the two invertebrate subphyla of chordates related to the vertebrate chordates? • Animals in the Subphylum Vertebrata retain the characteristics of the other chordates. • However, many of the additional features that separate the vertebrates from the other chordates are associated with a larger size and a mobile lifestyle. • A major additional feature is the head • Chordates with a head are known as craniates
Phylum Chordata • Previously covered from Phylum Chordata were the two subphyla of invertebrates • Tunicates • Lancelets • This packet will investigate SOME of the remaining organisms of this vast and wide phylum.
Phylum ChordataSubphylym VertebrataClass Agnatha • Include the lampreys and hagfishes. • Both are scales, elongate fish without jaws or paired fins • Hagfish are marine scavengers • Lampreys are found in freshwater or marine habitats and include ectoparasitic species.
Class Chondrichthyes • Includes sharks, rays and skates • Cartilaginous fish have 5 – 7 pairs of gills and rely on swimming to force water • Sharks, and their relatives, have paired fins and placoid scales. • Sharks may be oviparous, ovoviviparous or viviparous.
Class Osteichthyes • This class is the most speciose of the vertebrate classes. • Skeleton is composed of bone and is covered with overlapping flexible scales • Oviparous and produce a prodicious number of eggs.
Class Amphibia • Include frogs, toads and salamanders. • Some members lack tails • Toads & frogs • Some members lack legs • Tropical caecilians • The larvae of toads and frogs are aquatic • Some salamanders undergo neoteny. • Retention of juvenile characteristics in the adults of a species, as among certain amphibians. • Reflect back to past genetics packet. • Adult amphibians rely heavily on cutaneous respiration • The amphibian hear has three chambers (a atria and 1 ventricle) that allows a partially separated pulmonary and systemic circulation
Class Reptilia • Includes turtles, lizards, snakes and alligators • Terrestrial animals that do not rely on reproduce • Dinosaurs are thought to be reptiles. • Became extinct at some point in earth’s history • Bodies covered in dry scales to prevent cutansous respiration • Lungs are more efficient than amphibians. • Waste is excreted in the form of uric acid • Reduces water loss • Ectothermic organisms—similar to fish and amphibians • Most are carnivores • Snakes have unusual adaptations for efficient predation • Chemical and temperature senses • Produce toxins
Class Aves [ey-veez] • The anterior appendages of birds are winds and MOST birds do fly. • In order to fly, birds have skeletal reduction, efficient lungs, a four chambered heart, endothermy and frequent voiding of wastes. • Birds eat high energy foods to maintain a high metabolic rate. • The nervous system is cell developed • Sight and hearing • Display complex social behaviors, vocalizations and territorial behaviors.
Mammals • Mammals are characterized by hair and mammary glands. • Mammals have specializations in dentition, a diaphragm to aid in respiration, endothermy and a four chambered heart. • The nervous system, particularly the cerebrum, is quite advanced. • Fertilization is always internal and nearly all mammals are viviparous • Most mammals are placental • The limbs are adapted for diverse forms of locomotion
Monotremes • Subclass Prototheria • Mammals that lay eggs • Include the duck-billed platypus and spiny anteater (echidna). • When the young hatch, they feed on the milk produced by the mammary glands.
Marsupials • Subclass Metatheria • Pouched animals • Include kangaroos, koalas and opossums • Most common in Australia
Placental Mammals • Subclass Eutheria • Mammals that complete embryonic development within the mother. • The most common form of mammals. • There is a placental connection between the embryo and the mother in the uterus.