Vertebrate Characteristics

Classification Review Taxonomy - classifying organisms based on similarities and differences - assigning each organism a universally accepted name. Kingdom, Phylum, Class, Order, Family, Genus, Species In order from most general to most specific Acronym - Kings Play Chess On Fine Gold Squares Carolus Linnaeus

Classification of Vertebrates Phylum: Chordata Common Characteristics: notochord, pharyngeal gill slits, hollow dorsal nerve cord Lancelet Tunicate b. Sub-phylum: Vertebrata Common Characteristics: backbone that supports and protects spinal cord, endoskeleton, distinct head with skull and brain

Part A: Overview of Vertebrate Classes Fish - aquatic vertebrates that are characterized by scales, fins and pharyngeal gills. There are 3 main groups: jawless, cartilaginous and bony. Ex. Lamprey, dogfish shark, perch. Amphibians - vertebrates that are aquatic as larvae and terrestrial as adults. They breathe with lungs as adults, have a moist skin with glands and lack scales and claws. Ex. Frog, salamander, newt. Reptiles - vertebrates that have lungs, scaly skin and a special type of egg (amniotic). They live entire life out of water. Ex. Snake, lizard, turtle. Birds - endothermic, reptile-like vertebrates with feathers, two legs used for walking and perching and wings that usually don’t have claws. Ex. Pigeon, hawk, eagle. Mammals - endothermic animals with fur or hair, and mammary glands that produce milk to nourish young. Almost all give birth to live young. Ex. Human, whale, fetal pig.

Total Vertebrate Species: 62,305 (4.5%) Part A: Overview of Vertebrate Classes Total Animal Species: 1,367,555 Total Vertebrate Species: 62,305 (4.5%)

Part B: Important Evolutionary Advances Jaws in Fishes Fish are considered to be the most primitive living vertebrate. The first fishes to be found in abundance in the fossil record were jawless. These are limited to eating small particles of food by filter-feeding and vacuum suction. The evolution of jaws in fishes made it possible for them to eat plants and other animals and defend themselves by biting. Strength of Skeleton in Amphibians Amphibians probably evolved from lobe-finned fishes. These organisms faced many challenges transitioning from water to land. The first amphibians had strong limb bones and girdles for movement unsupported by water. The ribs formed a cage that supports and protects the internal organs.

c. Eggs Reptiles evolved from amphibians when climatic changes caused destruction of amphibian habitat. Reptilian eggs are surrounded by a shell and several membranes that create a protected environment for the embryo. These “amniotic eggs” contain nutrient-rich yolk used by the embryo for food.

d. Internal Temperature Control Fish, amphibians and reptiles are ectothermic. The have an internal body temperature that varies with external (environmental conditions) due to a slow metabolism. Birds and mammals are endothermic. They maintain a relatively high and constant internal body temperature that is regulated internally due to a fast metabolism. This adaptation is very important for animals living in habitats where temperatures and seasons are variable. Polar Bear Iguana Penguin

Part C: Comparing Structure and Function Feeding and Digestion

Part C: Comparing Structure and Function Feeding and Digestion Herbivorous Digestive Systems Carnivorous Digestive Systems - Eat constantly - Teeth and jaw adapted to breaking down cellulose - Long coiled digestive system which helps break down plant material - Microbes and specialized organs to assist with digestion - Eat less frequently - Shorter digestive system - Tongue, teeth and jaw adapted to catch, chew and swallow meat BENEFITS: Obtains energy efficiently from plants Generally food is readily available High calorie content in meat

Part C: Comparing Structure and Function Feeding and Digestion

Part C: Comparing Structure and Function Feeding and Digestion

Part C: Comparing Structure and Function Respiration

Part C: Comparing Structure and Function Respiration Gills: Oxygen rich water is pumped over gill filaments where gas exchange occurs. Oxygen poor water is pushed out through openings in the sides of the pharynx.

Part C: Comparing Structure and Function Respiration Alveoli: Final branchings of the respiratory tree and act as the primary gas exchange units of the lung. The gas-blood barrier between the alveolar space and the pulmonary capillaries is extremely thin, allowing for rapid gas exchange.

Part C: Comparing Structure and Function Respiration

Part C: Comparing Structure and Function Respiration Similarities Differences Lungs present in most vertebrate classes - adult amphibians, reptiles, birds, mammals. Gas exchange occurs in lungs Gills present in fish and amphibian larva Amphibians exchange gas through skin Air sac in birds allow for one way flow of air Diaphragm in mammals increases volume of lungs Benefits Lungs are more efficient than gills or skin gas exchange More surface area= more efficient

Part C: Comparing Structure and Function Circulation Single – Loop Circulation: Blood is carried in one loop: the heart to the gills, then to the body. Double – Loop Circulation: Blood is carried in two loops: one loop carries blood between the heart and the lungs, the second loop carries blood between the heart and the body.

Part C: Comparing Structure and Function Circulation Heart Chambers: Provide a multiple step pathway for blood to be sent to the lungs for respiration and dispensed to the body's cells.

Part C: Comparing Structure and Function Circulation

Deliver oxygen and nutrients to cells and remove wastes. Part C: Comparing Structure and Function Circulation DOUBLE LOOP One loop carries oxygen poor blood from heart to lungs and oxygen rich blood from lungs to the heart. The other loop carries oxygen rich blood from heart to rest of body and oxygen poor blood from the body to the heart. Amphibian Adults and Reptiles: 3 chambers in heart but less efficient due to single ventricle. Birds and Mammals: 4 chambers in heart. Complete separation of oxygen rich and oxygen poor blood= most efficient. SINGLE LOOP Closed system from heart to gills, from gills to the rest of the body and back to heart. Fish and Amphibian Larva: Two chambers in heart. Deliver oxygen and nutrients to cells and remove wastes.

Part C: Comparing Structure and Function Reproduction Oviparous: a vertebrate that lays eggs that develop outside the mothers body. Ovoviviparous: a vertebrate whose eggs develop inside the mother’s body but are not nourished directly by the mother’s body. Viviparous: a vertebrate who bears live young and directly nourishes the unborn young by the mother’s body.

Part C: Comparing Structure and Function Reproduction

Part C: Comparing Structure and Function Reproduction

Part C: Comparing Structure and Function Reproduction External Fertilization Internal Fertilization Benefits Large number of offspring produced No specialized reproductive structures needed With attention and maternal care, high percentage of offspring survive Drawbacks Low percentage of offspring survive with no parental care, eggs lost to predators Only small number of offspring produced Need specialized reproductive structures