Vertebrate Structure and Function

Transcription

1 Vertebrate Structure and Function Part 1 - Comparing Structure and Function Classification of Vertebrates a. Phylum: Chordata Common Characteristics: Notochord, pharyngeal gill slits, hollow dorsal nerve cord b. Sub-phylum: Vertebrata Common Characteristics: Backbone that supports and protects spinal cord, endoskeleton, distinct head with skull and brain 1

2 Part A: Overview of Vertebrate Classes 1. Vertebrate Class Definitions a. 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. b. 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. c. 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. d. 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. e. 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. Part B: Important Evolutionary Advances a. b. 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 filterfeeding 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. 2

3 c. Eggs in Reptiles Reptiles evolved from amphibians when climatic changes caused destruction of amphibian habitat. These organisms had to survive their entire lives on land. 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. Temperature Control in Birds and Mammals 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. 3

4 Part C: Comparing Structure and Function Among Vertebrates Feeding and Digestion a. Jaws and Teeth Part C: Comparing Structure and Function Among Vertebrates Feeding and Digestion a. Jaws and Teeth 4

5 Feeding and Digestion b. Digestive Systems Respiration a. Lungs 5

6 Respiration Fish Circulation/Internal Transport a. Heart Chambers and Circulatory Systems 6

7 Reproduction a. Definitions Oviparous: a vertebrate that lays eggs that develop outside the mothers body Ovoviviparous: a vertebrate whose young 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. b. Fertilization External: eggs are fertilized outside the mother s body. Adults release eggs and sperm into the surrounding water and sperm swim to the eggs to fertilized them. To increase chances, huge numbers of eggs and sperm are released. Internal: eggs are fertilized inside the mother s body. Sperm is deposited into the body of the female. This makes it possible for the female s reproductive system to cover the embryos with protective membranes and a shell after fertilization. 7