Evolution of the Tetrapods Evolution of the Tetrapods

Evolution of the Tetrapods

Evolution of the Tetrapods

Vertebrates

The Origin of Tetrapods The first vertebrates on land were amphibians in the Devonian (400 mya) u Arose from the rhipidistian (a family of lobed finned fish) (based on morhpology) or a lungfish (DNA) u

Origin of Tetrapods

Origin of Tetrapods

Classification u Phylum: Chordata u Subphylum: Vertebrata u Superclass: Gnathostomata u Class: Amphibia – Order: Urodela (Salamanders) – Order: Anurans (Frogs and Toads) – Order: Apodans (Caecilians)

Class: Amphibia Two lives – refers to metamorphosis of many frogs u Skin smooth and moist (cutaneous respiration) 3 u _____ chambered heart with a double circulation system u Mesolecithal eggs with jelly-like membrane u

Order: Urodela 400 species u Salamanders u Retain their tail as adults u Limbs are at right angles to the body u Carnivorous u Most have internal fertilization using a Spermatophore _______ u Axolotl paedomorphosis u

Order: Anurans 3500 species u Frogs and Toads u Lose their tail as adults u Hind limbs are adapted for jumping u Tongue connected to front of mouth u Secrete mucus External u _____ Fertilization u

Order: Apodans 150 species u Caecilians u Legless and blind u Mostly Tropical Internal u _____ Fertilization u Usually give birth to live young. u

Gas Exchange

Conditions for Respiratory Surfaces u Large u Thin u Moist surface area

Aquatic vs. Terrestrial 1 Less than ____% oxygen u Oxygen amounts decrease as the temperature increases u Aquatic animals use large amounts of energy to obtain 20 oxygen (____%) u 21 About _____% oxygen u Developed invaginations to increase surface area and decrease evaporation u Terrestrial animals may use only 1% 2% of its energy to obtain oxygen u

Respiratory Surfaces u Cutaneous Respiration u Gills u Tracheal u Lungs Systems

Cutaneous Respiration u Direct diffusion of gases between the organism and the environment u Found in Porifera, Cnidarians, Platyhelminthes, nematodes, Annelids, and some Amphibians u Supplements other organisms (amphibians)

Gills Found in echinoderms, mollusks, annelids, arthropods, some vertebrates u Countercurrent Gas Exchange u

Countercurrent Gas Exchange Maintains gradient over the whole length of the capillaries 80 u Extracts ____% of the oxygen from the water u

Tracheal Systems Found in arthropods u Tracheae u – open tubes u Spiracles – openings u Tracheoles – contact with cells u Muscle – increase amount of Carbon Dioxide removed

Tracheal Systems

Diffusion Lungs u Found in invertebrates u Gas moved primarily by diffusion – may be increased by body movement u Modifications – snails - cavity with gill modified into lung – scorpions and spiders - invaginations of the abdomen

Ventilation Lungs Found in amphibians, reptiles, mammals and birds u Pharynx u Larynx u Trachea u Bronchioles u Alveoli u

Alveoli

Ventilating The Lungs u _______ Positive Pressure Breathing – pushes air down trachea – seen in frogs and other amphibians u Negative Pressure ____ Breathing – suction created by diaphragm – seen in mammals

Negative Pressure Breathing

Amniotic Egg Evolution of the _____ u Allows animals to complete their entire life cycle on land u Has shell that retains water (or is lost when kept inside mammals) u Specialized extraembryonic membranes (not part of the animal)

The Amniotic Egg

Evolution of the Amniotic Egg u Amnion - Protects from dehydration and mechanical shock u Yolk Sac - Nutrient storage u Albumin (egg white) - Nutrient storage u Allantois - stores waste, gas exchange u Chorion - gas exchange

Amniotes

Amniotes

How Reptiles differ from Amphibians Tough, dry skin u Amniotic egg u Crushing or gripping jaws u Copulatory organs u More efficient circulatory system with a higher blood pressure u More developed lungs (thoracic breathing) u Better water conservation u Better body support and limbs u Better nervous system u

Classification u Phylum: Chordata u Subphylum: Vertebrata u Superclass: Gnathostomata u Class: Reptilia (not real) – Class: Testudines (Turtles and Tortoises) – Class: Spenodontia (Tuataras) – Class: Squamata (Lizards and Snakes) – Class: Crocodilia (Crocodiles and Alligators)

Reptile Radiation Synapsids (therapsids) led to mammals u Sauropsids u Anapsid – _____ (turtles) Diapsid – _____ (all others)

Class: Testudines (Chelonia) u Protective Shell – Carapace (top) – Plastron (bottom) u Land Sea Evolved on land returned to water (lay eggs on land) Largest, Leatherback Sea Turtle (2, 000 lbs!)

Class: Testudines (Chelonia) teeth No _____ u Most move legs to breathe u TDS (low: male high: female) u

Class: Sphenodontia u Tuataras ______ – Two living species (New Zealand) – Not a True Lizard (no external ears, different teeth) – Very Primitive (similar to mesozoic reptiles – Well developed eye below skin?

Class: Squamata u Lizards – geckos, iguanas, skinks, chameleons terrestrial, burrowing, aquatic, arboreal u moveable eyelids (in most) u Paired copulatory organs u

Class: Squamata Tongue usually not bifurcated u Lower jaw loosely connected to skull u TSD (female to male) Parthenogenesis u _______ u

Class: Squamata

Class: Squamata

Class: Squamata

Class: Squamata Gila Monster – • One of two poisonous lizards • Protein in saliva studied to treat diabetes.

Class: Squamata Snakes u Lack limbs u Lack moveable eyelids u

Class: Squamata Bifurcated tongue Jacobson’s organ u _____ u Pit Vipers (Loreal Pits) u

Class: Squamata u Venom – Viperidae (Folding Fangs) u Rattlesnakes – Elapidae (Fixed Front Fangs) u Cobras, Sea Snakes, Coral Snakes – neurotoxic – hemotoxic

Class: Squamata

Class: Squamata

Class: Squamata

Feeding Adaptations u Teeth curved and pointed inward Quadrate u Hinged _____ bone u Bones of jaw are attached by muscles and ligaments u Moveable palate u Elastic skin u No sternum

Largest living reptiles u Most closely related to dinosaurs u Complete secondary palate ____ u Four chambered heart (? ) u Nest temperature (female/male) u Class: Crocodilia

Dinosaurs and Pterosaurs u Dinosaurs – Ornithischian – Saurischian – Pterosaurs – flying reptiles

Animal Structure and Function (4 th exam)

Animal Nutrition

Nutritional Requirements u Undernourished – not enough calories u Overnourished – too many calories u Malnourished ______ – missing one or more essential nutrients

Essential Nutrients u Essential Amino Acids Fatty Acids Vitamins Minerals

Essential Amino Acids u Found in proteins – 20 different types u 8 essential in adult humans (9 infants) u all in animal proteins u vegetarians need to eat grains and beans

Histidine _____ – Essential in infants

Essential Fatty Acids u Unsaturated fatty acids – used to make phospholipids for membranes

Essential Vitamins u Fat Soluble – stored in fat D, A, K, E – ______ u Water Soluble – excreted in urine – B complex and C

Essential Minerals u Inorganic nutrients – Calcium & Phosphorous u bones – Iron u anemia – Iodine u thyroid hormones – Sodium, Chlorine, & Potassium u nerve function, water regulation

Food Types u Heterotrophic – Herbivores – Carnivores – Omnivores – Insectivores

Feeding Adaptations u Suspension Feeders

Feeding Adaptations u Substrate Feeders

Feeding Adaptations u Fluid Feeders

Feeding Adaptations u Bulk Feeders

Intracellular Digestion Inside cells u All animals u Exclusive in: u – Protista – Porifera

Extracellular Digestion u Outside cells u All animals above the sponges u Two Types Gastrovascular Cavity – _________ Alimentary Canal – _________

Gastrovascular Cavity One opening u Found in Cnidaria and Platyhelminthes u

Alimentary Canal Two openings u Allows for specialization u – Mouth – Pharynx – Esophagus – Crop – Gizzard – Stomach – Intestine – Anus

Mammalian Digestion u Accessory Glands – salivary glands – pancreas – liver (emulsification) – gallbladder u Peristalsis u Sphincters u “Food” – bolus – acid chyme – feces

Macromolecule Digestion

Dentition and Diet Nonmammal vertebrates u Carnivores u – canines (grasping/puncturing ) – incisors (tearing) – molars and premolars u (crushing grinding) Herbivores u Omnivores u and

Digestive Tracts u Carnivores u Herbivores shorter – ____ digestive system – small cecum – ____ Longer digestive system – large cecum