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Evolution of the Tetrapods
Evolution of the Tetrapods
The Origin of Tetrapods• The first vertebrates on land were
amphibians in the _________(400 mya)• Arose from the rhipidistian (a family of
lobed finned fish) (based on morhpology) or a lungfish (DNA)
Origin of Tetrapods
Classification
• Phylum: Chordata• Subphylum: Vertebrata• Superclass: Gnathostomata• Class: Amphibia
– Order: Urodela (Salamanders)– Order: Anurans (Frogs and Toads)– Order: Apodans (Caecilians)
Class: Amphibia• Two lives
– refers to metamorphosis of many frogs• Skin smooth and moist (cutaneous
respiration)• _____ chambered heart with a double
circulation system
Order: Urodela
• 400 species• Salamanders• Retain their tail as
adults• Limbs are at right
angles to the body• Carnivorous• Most have internal
fertilization using a _____________
• Axolotl - paedomorphosis
Order: Anurans• 3500 species• Frogs and Toads• Lose their tail as
adults• Hind limbs are
adapted for jumping• Tongue connected to
front of mouth• Secrete mucus• __________ Fertilization
Order: Apodans
• 150 species• Caecilians• Legless and blind• Mostly Tropical• __________
Fertilization• Usually give birth
to live young.
Gas Exchange
Conditions for Respiratory Surfaces
• Large surface area• Thin• Moist
Aquatic vs. Terrestrial• Less than ____%
oxygen• Oxygen amounts
decrease as the temperature increases
• Aquatic animals use large amounts of energy to obtain oxygen (____%)
• About _____% oxygen
• Developed invaginations to increase surface area and decrease evaporation
• Terrestrial animals may use only 1% - 2% of its energy to obtain oxygen
Gills• Found in echino-
derms, mollusks, annelids, arthropods, some vertebrates
• Countercurrent Gas Exchange
Countercurrent Gas Exchange• Maintains gradient over the whole length of
the capillaries• Extracts ____% of the oxygen from the
water
Tracheal Systems
Diffusion Lungs
• Found in invertebrates• Gas moved primarily by diffusion
– may be increased by body movement
• Modifications– snails - cavity with gill modified into lung– scorpions and spiders - invaginations of
the abdomen
Ventilation Lungs
• Found in amphibians, reptiles, mammals and birds
• Pharynx• Larynx• Trachea• Bronchi• Bronchioles• Alveoli
Alveoli
Ventilating The Lungs
• _______ Pressure Breathing– pushes air down
trachea– seen in frogs and
other amphibians
• ________ Pressure Breathing– suction created
by diaphragm– seen in
mammals
Negative Pressure Breathing
Evolution of the _________ Egg
• Allows animals to complete their entire life cycle on land
• Has shell that retains water (or is lost when kept inside mammals)
• Specialized extraembryonic membranes (not part of the animal)
The Amniotic Egg
Evolution of the Amniotic Egg
• Amnion - Protects from dehydration and mechanical shock
• Yolk Sac - Nutrient storage• Albumin (egg white) - Nutrient
storage• Allantois - stores waste, gas
exchange• Chorion - gas exchange• *** Good Essay….
Amniotes
How Reptiles differ from Amphibians
• Tough, dry skin• Amniotic egg• Crushing or
gripping jaws• Copulatory organs• More efficient
circulatory system with a higher blood pressure
• More developed lungs (thoracic breathing)
• Better water conservation
• Better body support and limbs
• Better nervous system
Classification
• Phylum: Chordata• Subphylum: Vertebrata• Superclass: Gnathostomata• 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
• Sauropsids– _________
(turtles)– _________ (all
others)
Class: Testudines (Chelonia)• Protective Shell
– Carapace (top)– Plastron (bottom)
• Land and Sea -Evolved on land and returned to water (lay eggs on land) Largest,
Leatherback Sea Turtle (2,000 lbs!)
Class: Testudines (Chelonia)
• No _____• Most move legs
to breathe • TDS (low:male
high:female)
Class: Sphenodontia• ___________
– 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• Lizards
– geckos, iguanas, skinks, chameleons
• terrestrial, burrowing, aquatic, arboreal
• moveable eyelids (in most)
• Paired copulatory organs
Class: Squamata• Tongue usually not
bifurcated• Lower jaw loosely
connected to skull• TSD (female to male)• ______________
Class: Squamata
Class: Squamata
Class: Squamata
Gila MonsterGila Monster – –
• One of three One of three poisonous lizardspoisonous lizards
• Protein in saliva Protein in saliva studied to treat studied to treat diabetes.diabetes.
Class: Squamata• Snakes• Lack limbs• Lack moveable
eyelids
Class: Squamata
• Bifurcated tongue • _________ organ• Pit Vipers (Loreal
Pits)
Class: Squamata
• Venom– Viperidae (Folding
Fangs)• Rattlesnakes
– Elapidae (Fixed Front Fangs)
• Cobras, Sea Snakes, Coral Snakes
– neurotoxic– hemotoxic
Class: Squamata
Feeding Adaptations
• Teeth curved and pointed inward• Hinged __________ bone• Bones of jaw are attached by
muscles and ligaments• Moveable palate• Elastic skin• No sternum
Class: Crocodilia• Largest living reptiles
• Most closely related to dinosaurs
• Complete secondary ________
• Four chambered heart (?)
• Nest temperature (female/male)
Dinosaurs and Pterosaurs
• Dinosaurs – Ornithischian– Saurischian– Pterosaurs– flying reptiles
Animal Structure and Function
(4th exam)
Animal Nutrition
Nutritional Requirements
• Undernourished– not enough
calories
• Overnourished– too many calories
• ____________– missing one or
more essential nutrients
Essential Nutrients
• Essential Amino Acids• Essential Fatty Acids• Essential Vitamins• Essential Minerals
Essential Amino Acids
• Found in proteins– 20 different types
• 8 essential in adult humans (9 infants)
• all in animal proteins• vegetarians need to
eat grains and beans
__________ – Essential in infantsHistidine
Essential Fatty Acids
• Unsaturated fatty acids– used to make phospholipids for
membranes
Essential Vitamins
• Fat Soluble– stored in fat– ___________
• Water Soluble– excreted in urine– B complex and C
Essential Minerals
• Inorganic nutrients– Calcium & Phosphorous
• bones
– Iron• anemia
– Iodine• thyroid hormones
– Sodium, Chlorine, & Potassium• nerve function, water regulation
Food Types
• Heterotrophic– Herbivores– Carnivores– Omnivores– Insectivores
Feeding Adaptations
• Suspension Feeders
Feeding Adaptations
• Substrate Feeders
Feeding Adaptations
• Fluid Feeders
Feeding Adaptations
• Bulk Feeders
Intracellular Digestion
• Inside cells• All animals• Exclusive in:
– Protista– Porifera
Extracellular Digestion
• Outside cells• All animals above the sponges• Two Types
– _________________– _________________
Gastrovascular Cavity
• One opening• Found in
Cnidaria and Platyhelminthes
Alimentary Canal
• Two openings• Allows for
specialization– Mouth– Pharynx– Esophagus– Crop– Gizzard– Stomach– Intestine– Anus
Mammalian Digestion• Accessory Glands
– salivary glands– pancreas– liver (emulsification)– gallbladder
• Peristalsis • Sphincters• “Food”
– bolus– acid chyme– feces
Macromolecule Digestion
Carbo Protein NucleicAcids
Fat
Mouth Initial
Stomach Initial
Intestine Main Main InitialMain
InitialMain
Dentition and Diet• Nonmammal
vertebrates• Carnivores
– canines (grasping/puncturing)
– incisors (tearing)– molars and premolars
• (crushing and grinding)
• Herbivores• Omnivores
Digestive Tracts
• Carnivores– ________
digestive system
– small cecum
• Herbivores– ________
digestive system
– large cecum