1. 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.
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2. 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.
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3. 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.
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4. 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.
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5. 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.
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6. 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.
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7. 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
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8. 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.
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9. 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.
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10. Add link animation from page 824 (figure 8) here.
Blood Flow in Fish
Animation
FPO
Add link animation from page 824 (figure 8) here.
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11. 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.
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12. 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.
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13. 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.
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14. 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.
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15. 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.
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16. 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
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