BY 124 1st Edition Lecture 12 Outline of Last Lecture Chapter 33 Coelomates cont I Phylum Crustacea Deuterostomes I II III Phylum Brachiopoda Phylum Echinodermata Phylum Hemichordata Chapter 34 I Phylum Chordata a 4 key characteristics of all chordates b Subphylum Craniata Outline of Current Lecture Chapter 34 cont I II 3 lineages of jawed vertebrates Tetrapods a Characteristics b Class Amphibia c Class Reptilia d Class Aves Current Lecture Chapter 34 cont I 3 lineages of jawed vertebrates 1 Chondrichthyans sharks rays a Skeleton composed of b Most are predators These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute c All vertebrates start off with a cartilaginous skeleton as embryo i Retained even after reaching maturity in this class d Traces of bone scales teeth e Have to swim to get oxygen that they need f 3 different types if fins dorsal pectoral and pelvic fins g No swim bladder Came from early lungs in fish i Can t stay at one depth h Osmoregulate differently have to keep high levels of urea in body i This makes them more like freshwater fish i Sharks have a ridge called a spinal valve that increases digestive surface area j Sharks have acute senses can detect electrical fields of muscles from nearby animals k Internal fertilization but embryos develop differently i Oviparous eggs hatch outside mother ii Ovoviviparous embryo develops within uterus and nourished by yolk iii Viviparous embryo develops within uterus and nourished through yolk sac placenta from mother s blood l Cloaca where reproductive tract excretory system and digestive tract empty 2 Ray finned fishes Subclass Actinopterygii a Actin ray b Osteichthyans bony endoskeleton c bony fish d Operculum draws water over gills e Swim bladder controls buoyancy f Lateral line system g Lay eggs external fertilization h Have 2 chambered heart alright because they don t have to worry about lungs i Ex Sea horse tuna eels j Nostrils do not use for breathing Use for smell 3 Lobe fins a Coelacanths i Thought to be extinct for 75 million years b Lung fish have a lung and can breathe air II Tetrapods 4 legs a Characteristics i Four limbs with digits ii Neck iii Fusion of pelvic girdle to backbone iv Absence of gills except some aquatic species v Ears b Class Amphibia 1 double life 2 3 chambered hearts a 2 atria and a ventricle i Oxygenated and deoxygenated blood mixes in ventricle 1 Okay because breathes across skin 3 1st vertebrates to come out on land 4 Have to return to water due to external fertilization 5 Came about during carboniferous period 6 Metamorphosis tadpole to frog a Tadpoles are herbivores b Adults are primarily carnivores eat insects ii Order Urodela salamanders 1 Can t lift off ground very well stay close to ground 2 Keep gills iii Order Anura frogs toads 1 Toads have poison glands 2 Some frogs do too poison dart frogs 3 Some frogs will carry eggs on back and form skin over them 4 Some have males carry them in their stomach until they hatch iv Order Apoda caecilians 1 without legs 2 Like snakes Good diagram to study Figure 34 2 c Class Reptilia 1 Amniotes have terrestrially adapted egg a Ex Reptiles birds and mammals b Amnion chorion yolk sac and allantois parts of land egg i Amnion enclose water around embryo ii Chorion important for gas exchange iii Yolk food iv Allantois sac that keeps nitrogenous waste away from embryo 2 Developed scales helps with water loss 3 Keratin 4 Internal fertilization 5 Have better lungs and limbs than amphibians 6 3 chambered hearts a Crocodiles are exception and have 4 chambers 7 Ectotherms can t regulate body temperature well a Why they are not considered real land dwellers ii Tuataras 1 Only 1 genus left 2 Have a 3rd eye on top off head that senses light iii Snakes 1 Most snakes have fangs a Coral snakes will chew you because they do not have good fangs 2 Many modes of predation a Constriction b Poison 3 Poison has a hemotoxin and a neurotoxin iv Turtles 1 Aquatic terrestrial and marine 2 Temperature effects sex not chromosomes v Crocodilians 1 Alligator a Very protective 2 Crocodile a Most dangerous of crocodilians b Crocodile s teeth show even when mouth is closed d Class Aves Birds i Feathers 1 Keratin in feathers 2 Came from scales ii No urinary bladder iii Only one ovary iv No teeth 1 But have genes for teeth v Hollow bones vi Air sacs vii Internal fertilization viii Some do not fly ix 4 chambered hearts x Well developed brain comparably but brain is mostly involved with instinctual stuff 1 Have fixed patterns xi Are not ectothermic can regulate temperature xii Take care of babies xiii Sexual dimorphism 1 Males and females look different xiv Age of birds Jurassic Period