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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu = invertebrates, including sea stars, sand dollars, sea urchins, sea cucumbers. They are symmetrical Starfish can and have unusual eating habits
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Adaptations of Vertebrates Vertebrates are with a backbone. They take their name from the individual segments, called vertebrae, that make up the backbone. In most vertebrates, the backbone completely replaces the found in invertebrate chordates. The backbone provides support for and protects a dorsal nerve cord. It also provides a site for Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu (Cat) Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Adaptations of Vertebrates, continued Vertebrates share a number of other characteristics, including, bilateral symmetry, and two pairs of jointed appendages, such as The of vertebrates compose organs. In turn, the organs compose organ Vertebrate organ systems tend to be more complex than the organ systems found in Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The First Vertebrates (today = species) The first chordates evolved about 550 million years ago. According to the fossil record, the first vertebrates appeared about million years later. The first vertebrates were. Unlike most of the fishes you are familiar with, the earliest fishes, called, had neither jaws nor paired fins. Within another 50 million years, fishes had diversified into a great variety of species. Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Among Chordates Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Evolution of Fishes This phylogenetic tree shows the relationship of the early fishes to later fishes and Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Evolution of Fishes, continued About 430 million years ago, the acanthodians, or, appeared. are thought to have evolved from gill arch supports made of cartilage a lightweight, strong, flexible tissue. About 20 million years after the acanthodians appeared, the placoderms, jawed fishes with massive heads with bony plates, evolved. Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Fish Classes The earliest fish were Acanthodians (with ) 1. Jawless Fish – class agnatha. Ancestors of oldest fish, no jaws, no paired fins, no scales. Ex: and hagfish. Hagfish attach to rip flesh to suck body fluids.
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Evolution of Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 2. Cartilagenous Fish Class – Skeleton made of cartilage ( ) Most are predators, Some (whale shark) are filter feeders. Some must move to get O over their Ex: Sharks, rays, skated, shark is largest shark. Sharks have a lateral line to sense pressure changes, have internal fertilization. Skin = many toothlike scales and modified pelvic fins called
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Class – Skeleton of bone, have a swim bladder to fill and empty to control position and level in the water. Most have external. Includes Ray fin fish (have bony rays) and lobe fins (fleshy fins) They have operculum covering the gills. They have a SWIM BLADDER – Like a, the fish can add air to or take air from this to move up or down in the water. BUOYANCY is the force water has pushing objects up. The swim bladder helps control the push of buoyancy. fish do not have a swim bladder.
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Evolution of Fishes, continued Sharks and Bony Fishes About million years ago, sharks and bony fishes appeared. Most sharks and bony fishes have streamlined bodies that are well adapted for movement through the water. Bony fishes have a skeleton made of bone, which is heavier and less flexible than cartilage. bulbs sense chemicals. Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Vertebrates in the Sea and on Land
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Key Characteristics of Modern Fishes All fishes share certain key characteristics: 1.. Fishes normally obtain oxygen from water with their gills. 2. Single-loop blood. Blood is pumped from the heart to the gills through the body and back to the heart again. 3. Vertebral (backbone). All fishes have an internal skeleton made of either cartilage or bone, with a vertebral column surrounding the spinal cord. The Fish Body
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The major respiratory organ of a fish is the gill. Gills are made up of rows of gill filaments—fingerlike projections through which gases enter and leave the The gill hang like curtains between a fish’s mouth and cheeks. At the rear of the cheek cavity is an opening called a gill slit. In countercurrent flow, water passes over the gills in one direction as blood flows in the opposite direction through in the gills. The Fish Body
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu in Fishes The Fish Body
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Circulation of Blood Fishes have a chamber-pump heart: 1. Sinus. This collection chamber acts to reduce the resistance of blood flow into the heart. It collcts deoxygenated blood. 2.. Blood from the sinus venosus fills this large chamber, which has thin, muscular walls. 3. Ventricle. Contractions of the ventricle pump the blood toward the 4. Conus arteriosus. This chamber is a second pump that smoothes the pulsations and adds still more The Fish Body
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The Fish Body
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Although the gills play a major role in maintaining a fish’s balance, another key element is a pair of kidneys. Salt water fish gain electrons. Kidneys are organs made up of thousands of nephrons. Nephrons are tubelike units that regulate the body’s salt and water balance and remove metabolic wastes from the Excess water and bodily wastes leave the kidneys in the form of a fluid called urine. is removed to make urine. The Fish Body
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Reproduction The sexes are in most fishes, and generally fertilization takes place externally. In a process called, male and female gametes are released near one another in the water. A yolk sac within each egg contains nutrients the developing embryo will need for growth. The eggs of, skates, and rays are fertilized inside the female’s body. The Fish Body
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Jawless Fishes Lampreys and hagfishes have scaleless, eel-like bodies with multiple gill slits and unpaired fins. Both have external fertilization. Their skeletons are made of cartilage, a strong fibrous connective tissue, and both kinds of fishes retain their notochord into adulthood. are scavengers of dead and dying animals on the ocean bottom, body fluids are like sea water, some are parasites. Most lampreys are parasitic on other living fishes. Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Cartilaginous Fishes ( ) Sharks, skates, and rays are cartilaginous fishes. Their skeletons are made of cartilage strengthened by the mineral calcium carbonate. Most – The shark’s light, streamlined body allows it to move quickly through the water in search of prey. Its contains embedded cone-shaped placoid scales, which give the skin a rough texture. They move to keep Two smaller groups of cartilaginous fishes, the and rays, have flattened bodies that are well adapted to life on the sea floor. Sharks have rows of teeth. Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bony Fishes Jawless and cartilaginous fishes are not as as bony fishes, which are the most numerous of all the fishes. Bony fishes have a fully developed system. The lateral line is a sensory system that extends along each side of a bony fish’s body. The lateral line system also enables a fish to detect a object by the movement of water deflected by that object. Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bony Fishes, continued Most bony fishes have a hard, an operculum, that covers the on each side of the head. Movements of certain muscles and of the opercula permit a bony fish to draw water over the gills, which enables the fish to take in Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Structure of Fish—Yellow Perch Today’s Fishes Know Pelvic & Caudal Fins & Lateral Line
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Internal Structure of Fish— Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ray-Finned Bony Fishes Ray-finned bony fishes comprise the vast majority of Their fins are supported by bony structures called Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Lobe-Finned Bony Fishes Only species of lobe-finned fishes survive today. One species is the coelacanth and the other six species are all In many lobe-finned fishes, each fin consists of a long, fleshy, muscular lobe that is supported by a central The of the amphibians most likely was a third type of lobe-finned fish that is now extinct. Today’s Fishes
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Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Other Groups have unique respiratory systems. have dry scaly skin. have thin, non-scaly skin.
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