Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
CHAPTER 24 Fishes 24-1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diversity Overview “Fish” has many usages extending beyond what are actually considered fishes today (e.g., starfish, etc.) A modern fish Fishes 24-3 Aquatic vertebrate with gills, limbs (if present) in the form of fins, and usually with a skin covered in scales of dermal origin In an evolutionary sense, can be defined as all vertebrates that are not tetrapods Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diversity 24-4 Common ancestor of fishes is also an ancestor of land vertebrates Approximately 24,600 living species Include more species than all other vertebrates combined Adapted to live in medium 800 times denser than air Can adjust to the salt and water balance of their environment-osmotic balance Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diversity 24-5 Gills are efficient at extracting oxygen from water that has 1/20 the oxygen of air Lateral line system detects water currents and vibrations, a sense of “distant touch” and used in schooling Evolution in an aquatic environment both shaped and constrained its evolution “Fish” refers to one or more individuals of one species “Fishes” refers to more than one species Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ancestry and Relationships of Major Groups of Fishes History Earliest fish-like vertebrates: Group of agnathan fishes Agnathans “jawless” 24-6 Include extinct ostracoderms and living hagfishes and lampreys Hagfishes lack vertebrae Lampreys have rudimentary vertebrae Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ancestry and Relationships of Major Groups of Fishes Gnathostomes “jawed” 24-7 Appear in the Silurian fossil record with fully formed jaws No intermediate forms between agnathans are known The Devonian is called the Age of Fishes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ancestry and Relationships of Major Groups of Fishes Cartilaginous Fishes 24-8 Lost heavy dermal armor and adopted skeleton of cartilage Flourished during the Devonian and Carboniferous Almost became extinct at end of the Paleozoic Increased in numbers in the early Mesozoic, diversifying to form a modern shark assemblage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ancestry and Relationships of Major Groups of Fishes Bony Fishes 24-10 Dominant fishes today Two distinct lineages Ray-finned fishes Lobe-finned fishes Ray-finned fishes radiated to form modern bony fishes Lobe-finned fishes are a relict group with few species today Include the sister group of the tetrapods Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Living Jawless Fishes Overview Living jawless fishes include hagfishes and lampreys 24-11 Members of both groups lack jaws, internal ossification, scales, or paired fins Both groups share porelike gill openings and an eel-like body Hagfish Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-12 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Living Jawless Fishes Hagfishes Entirely marine Scavengers and predators of annelids, molluscs, dead or dying fishes, etc. Enters dead or dying animal through orifice or by digging inside using keratinized plates on tongue Nearly blind To provide leverage Locate food by an acute sense of smell and touch Ties knot in tail and passes it forward to press against prey Special glands along body secrete fluid that becomes slimy in contact with seawater 24-14 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Living Jawless Fishes Reproduction of Hagfishes 24-15 Copenhagen Academy of Science offered a prize over a century ago for information on hagfish breeding habits………it remains unclaimed In some species, females outnumber males by 100 to 1 Females produce small numbers of large, yolky eggs 2-7 centimeters in diameter Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Living Jawless Fishes Lampreys Diversity 24-16 Marine lamprey Occurs on both Atlantic coastlines Grows to a length of one meter 20 species of lampreys in North America Half belong to nonparasitic brook-dwelling species Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-17 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Living Jawless Fishes Parasitic Lampreys Marine, parasitic lampreys migrate to the sea Other species remain in freshwater Attach to a fish by a sucker-like mouth Sharp teeth rasp through flesh as they suck fluids Inject anticoagulant into a wound When engorged, lamprey drops off but wound may be fatal to fish Parasitic freshwater adults live 1–2 years before spawning and dying Anadromous forms live 2–3 years Nonparasitic lampreys do not feed 24-18 Digestive tract degenerates as an adult They spawn and die Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-19 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Living Jawless Fishes Sea Lamprey Invasion of the Great Lakes Region No lampreys were in the U. S. Great Lakes west of Niagara Falls until the Welland Ship Canal was deepened between 1913 and 1918 Lampreys preferred lake trout Destroyed this commercial species along with overfishing Lamprey populations declined both from depletion of food and control measures 24-20 Chemical larvicides in spawning streams Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Chondrichthyes: Cartilaginous Fishes Overview Well-developed sense organs, powerful jaws, and predaceous habits helped them survive True bone is completely absent throughout the class Phosphatized mineral tissues retained in teeth, scales, and spines Nearly all are marine Only 28 species live primarily in freshwater After whales, sharks are the largest living vertebrates, reaching 12 meters in length 24-21 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Chondrichthyes: Cartilaginous Fishes Sharks, Skates and Rays 24-22 coastal tiger and bull sharks and the hammerhead large, pelagic sharks such as the white and mako shark dogfish sharks skates several groups of rays (stingrays, manta rays, etc.) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-23 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Chondrichthyes: Cartilaginous Fishes 24-24 Form and Function of Sharks Sharks are among the most gracefully streamlined of fishes In males, part of the pelvic fin is modified to form a clasper used in copulation Lateral eyes are lidless Behind each eye is a spiracle Remnant of the first gill slit Tough, leathery skin with placoid scales Reduce water turbulence Detect prey at a distance by large olfactory organs sensitive to one part per 10 billion Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-25 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-26 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Chondrichthyes: Cartilaginous Fishes 24-27 Nostrils to each side of the hammerhead shark may improve stereo-olfaction Prey may also be located from long distances sensing low frequency vibrations in the lateral line Consists of neuromasts in interconnected tubes and pores on side of body At close range, switch to vision Most have excellent vision even in dimly lit water Up close, sharks are guided by bioelectric fields that surround all animals Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-28 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Chondrichthyes: Cartilaginous Fishes 24-29 Electroreceptors, the ampullae of Lorenzini, are located on the shark’s head Upper and lower jaws equipped with sharp, triangular teeth (modified placoid scales) that are constantly replaced Spiral valve in intestine slows passage of food and increases absorptive area Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-30 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Chondrichthyes: Cartilaginous Fishes Reproduction and Development 24-31 Fertilization is internal Maternal support of embryo is variable Includes oviparous, ovoviviparous, and viviparous species “Mermaid’s purse” capsule encasing eggs laid by some oviparous species Sharks Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Chondrichthyes: Cartilaginous Fishes Rays & Skates 24-32 Most specialized for benthic life flattened body and enlarged pectoral fins used to propel themselves Respiratory water enters through large spiracles on top of the head to prevent clogging of gills. Teeth adapted for crushing prey Molluscs, crustaceans, and sometimes small fish Stingrays Have whiplike tail with spines and venom glands Electric rays Have large electric organs on each side of head Stingrays Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-33 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Chondrichthyes: Cartilaginous Fishes Chimeras Small subclass Fossil chimaeras Remnants of a line that diverged from the earliest shark lineage 33 extant species First appeared in the Carboniferous, reached a zenith in the Cretaceous and early Tertiary, and then declined Mouth lacks teeth 24-34 Equipped with large flat plates for crushing food Upper jaw fused to the cranium Feed on seaweed, molluscs, echinoderms, crustaceans, and fish Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-35 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Osteichthyes: Bony Fishes Origin, Evolution and Diversity In early to middle Silurian, a lineage of fishes with bony endoskeletons gave rise to a clade that contains 96% of living fishes and all living tetrapods 3 features unite bony fishes and tetrapod descendants 24-36 Endochondral bone replaces cartilage during development Lung or swim bladder is present Evolved as an extension of gut Have several cranial and dental characters unique to clade Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-37 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Osteichthyes: Bony Fishes 2 major lineages Operculum increased respiratory efficiency 24-38 Ray-finned fishes,modern bony fishes Lobe-finned fishes, lungfishes and the coelacanth Helped draw water across gills Gas-filled structure off the esophagus Helped in buoyancy and also in hypoxic waters In fishes that use these pouches for respiration Pouches are called lungs In fishes that use these pouches for buoyancy Pouches are called swim bladders Specialization of jaw musculature improved feeding Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-39 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ray-finned Fishes Morphological Trends Heavy dermal armor replaced by light, thin, flexible cycloid and ctenoid scales Fins changed to provide greater mobility and serve a variety of functions Some eels, catfishes, and others lost scales Increased mobility from shedding armor helps fish avoid predators and improved feeding efficiency Braking, streamlining, and social communication Jaw changed to increase suctioning and protrusion to secure food 24-40 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Sarcopterygii: Lobe-finned Fishes Diversity Ancestor of tetrapods Early sarcopterygians Group of extinct sarcopterygian fishes called rhipdistians Had lungs, gills Had powerful jaws, heavy, enameled scales with a dentine-like material called cosmine, and strong, fleshy, paired lobed fins Today, clade is represented by 8 fish species 24-41 6 species of lungfishes and 2 species of coelacanths Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-42 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Sarcopterygii: Lobe-finned Fishes Lungfish 24-43 Australia lungfishes, unlike close relatives, rely on gill respiration and cannot survive long out of water South American and African lungfish can live out of water for long periods of time Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-44 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Class Sarcopterygii: Lobe-finned Fishes The Coelacanth 24-45 Thought to be extinct 70 million years, a specimen was dredged up in 1938 More were caught off coast of the Comoro Islands and in Indonesia Young coelacanths born fully formed after hatching from eggs up to 9 cm in diameter Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Locomotion in Water Speed Most fishes swim maximally at ten body lengths per second Larger fish therefore swims faster Short bursts of speed are possible for a few seconds Mechanism Trunk and tail musculature propels a fish Muscles are arranged in zigzag bands called myomeres 24-46 Have the shape of a W on the side of fish Internally the bands are folded and nested Each myomere pulls on several vertebrae Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-47 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-48 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Economy 24-49 Swimming is the most economical form of motion because water buoys the animal Energy cost per kilogram of body weight for traveling one kilometer is 0.39 Kcal for swimming, 1.45 Kcal for flying, and 5.43 for walking Yet to be determined how aquatic animals can move through water with little turbulence Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Neutral Buoyancy and the Swim Bladder Fish are slightly heavier than water To keep from sinking, a shark must continually move forward Fins keep it “angled up” Shark liver has a special fatty hydrocarbon, or squaline, that acts to keep the shark a little buoyant Swim bladder, as a gas-filled space, is the most efficient flotation device 24-50 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Hearing and Weberian Ossicles Fish, like other vertebrates, detect sounds as vibrations in the inner ear. Weberian ossicles 24-51 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-52 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Respiration Fish gills are filaments with thin epidermal membranes folded into plate-like lamellae Gills are inside the pharyngeal cavity and covered with a movable flap, the operculum Operculum protects delicate gill filaments and streamlines body Pumping action by operculum helps move water through gills Although it appears pulsatile, water flow over gills is continuous 24-53 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-54 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Water flow is opposite to the blood flow Countercurrent exchange maximizes exchange of gases Some bony fishes remove 85% of the oxygen from water passing over gills Some active fishes use ram ventilation 24-55 Forward movement is sufficient to force water across gills Such fishes are asphyxiated in a restrictive aquarium even if the water is saturated with oxygen Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Fishes Out of Water Lungs of lungfishes allow them to respire in air Eels can wriggle over land during rainy weather 24-56 Use skin as major respiratory surface A bowfin uses gills at cooler temperatures and lung-like swim bladder at higher temperatures Electric eel has degenerate gills and gulps air through vascular mouth cavity Indian climbing perch spends most of its time on land, breathing air in special chambers Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Osmotic Regulation Freshwater is hypotonic to fish blood Water enters body and salt is lost by diffusion Scaled and mucous-covered body is mostly impermeable, but gills allow water and salt fluxes Freshwater fishes are hyperosmotic regulators 24-57 Opisthonephric kidney pumps excess water out Special salt-absorbing cells located in epithelium actively move salt ions from water into fishes’ blood Systems are efficient Freshwater fish devote little energy to maintaining osmotic balance Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes About 90% of bony fishes are restricted to either freshwater or seawater habitats Marine bony fishes are hypoosmotic regulators 24-58 Blood is hypotonic to seawater Tend to lose water and gain salt Risks “drying out” To compensate for water loss, a marine teleost drinks seawater Brings in more unneeded salt Carried by blood to gills and secreted by special salt-secretory cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Feeding Behavior Fish devote most of their time searching for food to eat and eating With the evolution of jaws Most fish are carnivores Fish left a passive filter-feeding life and entered a predator-prey battle Feed on zooplankton, insect larvae, and other aquatic animals Most fish do not chew food 24-59 Would block water flow across the gills Blue fin tuna Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes A few can briefly crack prey items with teeth, or have molar-like teeth in throat Most swallow food whole Some are herbivores Easy with water pressure that sweeps food in when the mouth opens Eat plants and algae Crucial intermediates in food chain Suspension feeders 24-60 Crop abundant microorganisms of the sea Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Many plankton feeders swim in large schools and using gill rakers to strain food Omnivores feed on both plants and animals Scavengers feed on organic debris Detritovores consume fine particulate organic matter Parasitic fishes suck body fluids of other fishes Digestion follows the vertebrate plan 24-61 A few lack stomachs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Intestine tends to be shorter in carnivores and long and coiled in herbivores Stomach primarily stores food Intestine digests and absorbs nutrients Teleost fishes have pyloric ceca 24-62 Apparently for fat absorption Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Homing Salmon Salmon are anadromous Grow up in sea but return to freshwater to spawn 6 species of Pacific salmon and 1 Atlantic salmon migrates Atlantic salmon makes repeated spawning runs Pacific species spawn once and die 24-63 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-64 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Pacific species of sockeye salmon Migrates downstream Roams the Pacific for 4 years Returns to spawn in headwaters of parents’ stream Young fish are imprinted on odor of their stream May navigate to stream mouth by sensing magnetic field of the earth or angle of the sun, and then smelling their way home Salmon are endangered by stream degradation from logging, pollution and hydroelectric dams 24-65 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Reproduction and Growth Most fishes are dioecious with external fertilization and external development Guppies and mollies represent ovoviviparous fish that develop in ovarian cavity Some sharks are viviparous with some kind of placental attachment to nourish young Most oviparous pelagic fish lay huge numbers of eggs 24-66 Female cod may release 4–6 million eggs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-67 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Near-shore and bottom-dwelling species lay larger, typically yolky, nonbuoyant and adhesive eggs Some bury eggs Many attach eggs to vegetation Some incubate eggs in their mouth 24-68 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-69 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Many benthic spawners guard eggs Freshwater fishes produce nonbuoyant eggs Male is usually the guard The more care provided, the fewer the eggs produced Freshwater fishes may have elaborate mating dances before spawning Egg soon takes up water, the outer layer hardens and cleavage occurs 24-70 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structural and Functional Adaptations of Fishes Blastoderm develops and yolk is consumed Fish hatches carrying a semitransparent yolk sac to supply food until it can forage Change from larva to adult may be dramatic in body shape, fins, color patterns, etc. Growth is temperature dependent Warmer fish grow more rapidly Annual rings on scales, otoliths, etc. reflect seasonal growth cycles Most fish continue to grow throughout life 24-71 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 24-72