Reviewer in Finals for Zoology

• All chordates posess an notochord
• Homeostasis - refers to the relatively stable state inside the body of an animal
• Stimulus - A change in the internal and external environment
• Receptor - Detected or skin
• Ecthoterm - Cold Blooded animals and do not have internal control of their body temperature
• Thermoregulation - Coordinated by the nervous system
• Temperature control are centered in the hypothalamus of the advance animal brain
• Osmoregulation - the process of maintaining salt and water balance
• Electrolyte - A compound that dissociates into ions when dissolved in water
• Nonelectrolyte - do not dissociates into ions in water
• Characteristics of Chordates - Notochord, Nerve Cord, Pharangeal Slits
• Urochordata is commonly called as tunicates
• Filter feed through use of siphon
• Cephalochordata also knows as lancelets
• Lancelets - filter food through mouth
• Subphylum Vertabrata has 7 extant classes the first 3 is commonly fishes and remaining 4 called tetrapods
• Class Agnatha is commonly known as Jawless fish include hagfish and lampreys
• examples of Class chondrichthyes - sharks, skates, rays
• Called cartilagenous fish because skeleton is cartilage and not bone
• Class osteichthyes are called bony fishes
• Bony flap called operculum
• Class Agnatha - Lack Paired Appendages
• Class Agnatha - Lack bony skeleton
• Class Agnatha - lack jaws
• Class Agnatha - usually have circular sucking mouthparts
• Lampreys parasitize other fish
• Class Chondrichthyes - approx 750 species
• Class Chondrichthyes - have paired appendages
• Sharks have lateral-line system
• Operculum - allows water to be drawn over gills by fins
• Swim Bladder - Gas content can be manipulated allowing changes in bouyancy
• Order Urodela - Salamander and Newts
• Urodela means tailed ones
• Class Apoda - tail less ones, frogs and toads
• Frogs


  • Have more developed lungs than salamanders
  • Lack a diaphragm & must "swallow" air
  • Most diverse and common of amphibians
• Toads


  • Are the first amphibians to evolve keratinized skin
  • This waterproofs the skin
• Caecilia or legless ones
• Amphibians


  • Lack internal fertilization
  • Lay amniotic eggs
  • Reproduction must occur in H2O
  • Most species undergo metamorphosis
  • Larval stage (tadpole) is usually an aquatic herbavore
  • Lacks legs, respiration is through gills
  • Develops into tetrapod adult (usually carnivorous)
• Class Reptilia


  Includes lizards, snakes, turtles, and crocodilians
• Over 7000 species of reptiles