Characteristics of Vertebrates Animals belonging to subphylum Vertebrata have a vertebral column and specialized cells that develop from the nerve cord. Classes of vertebrates include fishes, amphibians, reptiles, birds, and mammals. Copyright © McGraw-Hill Education Fishes

Characteristics of Vertebrates Vertebral column The notochord is replaced by a vertebral column that protects and surrounds the dorsal nerve cord. Made of cartilage – flexible tough material found in skeletons, or bone The vertebral column functions as a strong, flexible rod that muscles can pull against during swimming or running. Copyright © McGraw-Hill Education Fishes

Characteristics of Vertebrates Neural crest A neural crest is a group of cells that develop from the nerve cord in vertebrates. Portions of the brain and skull, certain sense organs, and some nerve fibers are some of the structures that develop from the neural crest. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Fishes are found in a variety of aquatic habitats including seas, lakes, ponds, streams, and marshes. Most fishes have vertebral columns, jaws, paired fins, scales, gills, and single-loop blood circulation. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Jaws Anterior gill arches evolved into jaws in ancient fishes. The development of jaws allowed ancient fishes to prey on a larger range of animals. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Paired fins A fin is a paddle-shaped structure on a fish or other aquatic animal that is used for balance, steering, and propulsion. Paired fins reduce the chance of rolling to the side and allow for better steering during swimming. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Scales Scales are small, flat, platelike structures near the surface of the skin Ctenoid scales – made of bone and skin Cycloid scales – made of bone and skin Placoid scales – made of toothlike material Ganoid scales – made of enamel and bone Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Gills Fishes get oxygen when water that enters their mouths flows across their gills, where oxygen from the water diffuses into the blood. The flow of blood in the gills is opposite the flow of water across the gills, allowing for more efficient uptake of oxygen Some fish protect their gills with operculum, a movable flap. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Circulation Vertebrates have a closed circulatory system. In most fishes, the heart consists of two main chambers – the atrium, where the heart receives blood from the body, and the ventricle, where the heart pumps blood to the gills. Copyright © McGraw-Hill Education Fishes

Add link animation from page 824 (figure 8) here. Blood Flow in Fish Animation FPO Add link animation from page 824 (figure 8) here. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Feeding and digestion Ancient fishes were most likely filter feeders and scavengers. Most fishes swallow their food whole, passing it through a tube called the esophagus to the stomach, where digestion begins. Fishes and subsequent vertebrates are unable to synthesize certain amino acids, and must get them from food. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Excretion Cellular wastes are filtered from fishes’ blood by the kidneys. A nephron is a filtering unit within the kidney that helps maintain the salt and water balance of the body and to remove cellular waste products from the blood. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes The brain and senses Color vision, chemical detection, hearing, and balance are coordinated in the brain. The lateral line system is a sensory system the allows fish to detect movement in the water, and also helps to keep them upright and balanced. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Reproduction The majority of fishes reproduce through external fertilization, but some do have internal fertilization. Male and female fishes release their gametes near each other in the water in a process called spawning. Developing embryos get nutrition from the yolk of their eggs. Many fish produce large numbers of eggs and exhibit little care for their offspring. Copyright © McGraw-Hill Education Fishes

Characteristics of Fishes Movement Most fish have a streamlined shape for moving through water. Mucus lubricates their body Have a gas-filled space called a swim bladder that allows a fish to control it’s depth Fishes move through the water by contracting muscle groups on either side of their bodies. Copyright © McGraw-Hill Education Fishes

Review Essential Questions Vocabulary What are the features of vertebrates that make them different from invertebrates? What are the characteristics that most fishes have in common? How are the characteristics of fishes adapted to aquatic life? Vocabulary cartilage neural crest fin scale operculum atrium ventricle nephron lateral line system spawning swim bladder Copyright © McGraw-Hill Education Fishes