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 Chordata Subphylym Vertebrata Class 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.

Review I Vertebrates Phylum Chordata Subphylum Vertebrata DeuterostomesCoelomatesEndoskeleton Closed Circulatory System Ventral Heart

Review II Phylum Chordata Invertebrates Tunicates Lancelets Vertebrates Jawless Fish Cartilaginous Fish Bony Fish Amphibians Reptiles Birds Mammals

Review III Mammals Monotremes Subclass Prototheria Mammals that lay eggs Marsupials Subclass Metatheria Pouched animals Placental Mammals Subclass Eutheria Embryonic development in the mother