Comparative Anatomy of Respiratory Systems: Fish, Frog, Pigeon and Rabbit

Total Page:16

File Type:pdf, Size:1020Kb

Comparative Anatomy of Respiratory Systems: Fish, Frog, Pigeon and Rabbit COMPARATIVE ANATOMY OF RESPIRATORY SYSTEMS: FISH, FROG, PIGEON AND RABBIT What is respiration? Exchange of gases (O2 and CO2) The process in which oxygen is taken inside the body from the envt for oxidation of food to release energy & CO2 so produced is expelled out Physiology of respiration 1. External respiration: Inspiration & expiration 2. Exchange of gases between alveolar air and blood 3. Internal respiration :Transportation of O2 from blood to tissues, oxidation of food, energy release, Co2 back to resp. surface for expulsion MovementFlowchart of Oxygen and Carbon SectionDioxide 37-3 In and Out of the Respiratory System Oxygen-rich Nasal air from environment Pharynx Trachea cavities Bronchi Oxygen and carbon dioxide Bronchi Bronchioles Alveoli Bronchioles exchange at alveoli Carbon Nasal dioxide-rich Trachea Pharynx cavities air to the environment BIG QUESTION WHY DO ANIMALS BREATHE? … Why? Just like machines, we also need energy!!! Energy is unlocked from macromolecules like CHO, fats & proteins by oxidation Evolutionary significance of pharynx Organs of resp. (both aq. & terrestrial) are derived from pharynx Pharynx for food passage from mouth to oesophagus It opens to lungs through trachea by means of an opening, glottis Dorsally open to Eustachian tube Not much used now in amniotes- vestige Respiration in animals Whether they live in water or on land, all animals must respire. ◦ To respire means to take in oxygen and give off carbon dioxide. Some animals rely of simple diffusion through their skin to respire. While others… Have developed large complex organ systems for respiration. Respiratory organs 1. Gills : Fish, larval amphibians, adult urodeles 2. Swim bladder: Fishes 3. Lungs: Tetrapods 4. Skin/ cutaneous resp: Amphibians The basic necessities of any respiratory organ 1. The respiratory organs must be thin walled so that there is easy diffusion of gases 2. It must be richly supplied with blood enable exchange of gases 3. It should have large area for contraction and expansion. I. GILLS 1. Fishes 2. Amphibian’s larva/ Tadpole 3. Adult urodelian amphibians Gills are the respiratory organs. Development of gills 1. In the embryo the pharynx develops paired pouches due to evagination or pushing out. 2. At the same time skin develop grooves due to invagination or pughing in 3. when the pouch and the groove meet the membrane between the two disentigrates and a slit develops to form gill slit Development of gills 4. The gill cleft or slit contains gills which are present in a gill chamber 5. Each gill chamber has an internal branchial aperture opening to pharynx 6. An external branchial aperture opens to external 7. The gill chambers are separated by inter branchial septa and supported by gill rays Development of gills 8. Each half of the gill filament is called Demibranch. 9. The demibranch on either side of interbranchial septum. gillrays, connective tissue and associated blood vessels with nerves form a holobranch. 10. The demibranch at the anterior end is called pretrematic demibranch and at the posterior end is called post trematic demibranch. Gills in fishes The gills are internal and vary in number depending on the classes they belong to. Operculum is a bony flap like covering that is seen over the gill slits on either sides in bony fishes. Aquatic Gills Water flows through the mouth then over the gills where oxygen is removed Carbon dioxide and water are then pumped out through the operculum What are bony fishes and cartilaginous fishes? Cartilaginous fishes Bony fishes (Elasmobranches or Chondrichthyes) (Teleosts/ Osteichthyes) 1. 5 pairs of gill slits 1. 4 pairs of gill slits 2. A pairs of spiracle in front of the 2. No Spiracles hyomandibular arch 3. Operculum is absent 3. Operculum present 4. Gills open to the exterior by inter 4. Gills open to the opercular branchial aperture chamber 5. No opercular chamber 5.Opercular chamber is present 6. 1 demibranch & 5 Holobranches 6. 4 holobranch, the demibranch of the first gill is lost GILLS IN AMPHIBIANS Amphibian tadpoles are purely aquatic, they need to utilize oxygen in the water- help of gills. Initially 3 pairs of external gills (gills that are constantly bathed in water)- internal gills-Lungs Only in Urodeles like Salamanders and Necturus, 3 pairs of external gills persist through out the life. ANURA Anya Urodeles? SWIM BLADDER/ AIR BLADDER- Development Swim bladder or air bladder are paired or unpaired structures arise from the pharynx or oesophagus of bony fishes The air bladder arise as an outgrowth of the pharynx on either side, initially lateral in position then becomes dorsal It is below vertebral column and outside Coelom. SWIM BLADDER/ AIR BLADDER Connection between b/w the pharynx and airbladder is called pneumatic duct. SB serves both as respiratory and hydrostatic organ. Richly supplied with blood capillaries In lung fishes the SB resembles the lungs & makes respiration more effective eventhough they have lesser no of demibranches SWIM BLADDER/ AIR BLADDER- How is it working? When the fish gulps in air, it enters through mouth, pharynx, pneumatic duct Oesopharyngeal pumb forces air into pneumatic duct When air bladder is compressed, gas exchange & CO2 is expelled through the mouth as bubbles. SectionFigure 33-3 33–10: Vertebrate Lungs Nostrils, mouth, and throat Trachea Lung Air sac Salamander Lizard Primate Pigeon Figure 37-13 The Respiratory System SectionThe 37-3 Human Respiratory System Lungs From amphibians to mammals all terrestrial org. has lungs Formation of lungs 1. Lungs develop from the floor of pharynx at its posterior end as a small bud called lung bud single through single evagination. 2. The lung bud slightly elongates & bifurcates into two 3. The opening of lung bud into the pharynx develops a small slit & form the glottis. 4. The part after glottis forms the larynx (voice box) 5. The elongated part of the lungs before bifurcation forms Trachea (air pipe) 6. The bifurcated part becomes the bronchi 7. The ends of bifurcated parts of the lung buds expand to form lungs. 8. The lungs push backwards & come to lie on either side of the heart. 9. Lungs get surrounded by coelomic epithelium LARYNX TRACHEA AIRSACS IN BIRDS LUNGS LARYNX Part between glottis and upper end of trachea, well developed in tetrapods Larynx in Amphibia a. In anurans there is a laryngo-tracheal chamber for production of sound (urodeles and apodans do no not produce sound) b. Laryngo-tracheal chamber: 3 cartilaginous structure to keep it stretched-one ring like cricoid cartilage and two semicircular arytenoids cartilage Larynx in Reptiles Similar as in frog. Has well developed hyoid cartilage to hold larynx in position Larynx in Birds Simple Another organ for sound Production- Syrinx Larynx in Mammals Highly developed-3 cartilages Thyrenoid/ thyroid cartilage: @ ant end of larynx Dorsal to thyroid cartilage is the arytenoids Below arytenoids is the crinoids, followed by trachea. Epiglottis (fold of mucous membrane of pharynx)-@ ant to glottis Erect while breathing, close the glottis while eating Sound: a pair of vocal cords b/w thyroid & arytenoids cartilages TRACHEA A duct that connect pharyngeal cavity to lungs Trachea bifurcates into - two bronchi – Each bronchus enter to lungs – bronchioles (pimary, secondary , tertiary and terminal) .
Recommended publications
  • Pond-Breeding Amphibian Guild
    Supplemental Volume: Species of Conservation Concern SC SWAP 2015 Pond-breeding Amphibians Guild Primary Species: Flatwoods Salamander Ambystoma cingulatum Carolina Gopher Frog Rana capito capito Broad-Striped Dwarf Siren Pseudobranchus striatus striatus Tiger Salamander Ambystoma tigrinum Secondary Species: Upland Chorus Frog Pseudacris feriarum -Coastal Plain only Northern Cricket Frog Acris crepitans -Coastal Plain only Contributors (2005): Stephen Bennett and Kurt A. Buhlmann [SCDNR] Reviewed and Edited (2012): Stephen Bennett (SCDNR), Kurt A. Buhlmann (SREL), and Jeff Camper (Francis Marion University) DESCRIPTION Taxonomy and Basic Descriptions This guild contains 4 primary species: the flatwoods salamander, Carolina gopher frog, dwarf siren, and tiger salamander; and 2 secondary species: upland chorus frog and northern cricket frog. Primary species are high priority species that are directly tied to a unifying feature or habitat. Secondary species are priority species that may occur in, or be related to, the unifying feature at some time in their life. The flatwoods salamander—in particular, the frosted flatwoods salamander— and tiger salamander are members of the family Ambystomatidae, the mole salamanders. Both species are large; the tiger salamander is the largest terrestrial salamander in the eastern United States. The Photo by SC DNR flatwoods salamander can reach lengths of 9 to 12 cm (3.5 to 4.7 in.) as an adult. This species is dark, ranging from black to dark brown with silver-white reticulated markings (Conant and Collins 1991; Martof et al. 1980). The tiger salamander can reach lengths of 18 to 20 cm (7.1 to 7.9 in.) as an adult; maximum size is approximately 30 cm (11.8 in.).
    [Show full text]
  • Ontogenetic Evidence for the Paleozoic Ancestry of Salamanders
    EVOLUTION & DEVELOPMENT 5:3, 314–324 (2003) Ontogenetic evidence for the Paleozoic ancestry of salamanders Rainer R. Schocha and Robert L. Carrollb aStaatlilches Museum für Naturkunde, Rosenstein 1, D-70191 Stuttgart, Germany bRedpath Museum, McGill University, Montréal, Québec, Canada, H3A 2K6 Authors for correspondence (e-mail: [email protected], [email protected]) SUMMARY The phylogenetic positions of frogs, sala- tire developmental sequence from hatching to metamor- manders, and caecilians have been difficult to establish. phosis is revealed in an assemblage of over 600 Data matrices based primarily on Paleozoic taxa support a specimens from a single locality, all belonging to the genus monophyletic origin of all Lissamphibia but have resulted in Apateon. Apateon forms the most speciose genus of the widely divergent hypotheses of the nature of their common neotenic temnospondyl family Branchiosauridae. The se- ancestor. Analysis that concentrates on the character quence of ossification of individual bones and the changing states of the stem taxa of the extant orders, in contrast, configuration of the skull closely parallel those observed in suggests a polyphyletic origin from divergent Paleozoic the development of primitive living salamanders. These clades. Comparison of patterns of larval development in fossils provide a model of how derived features of the sala- Paleozoic and modern amphibians provides a means to mander skull may have evolved in the context of feeding test previous phylogenies based primarily on adult charac- specializations that appeared in early larval stages of mem- teristics. This proves to be highly informative in the case of bers of the Branchiosauridae. Larvae of Apateon share the origin of salamanders.
    [Show full text]
  • An Introduction to the Classification of Elasmobranchs
    An introduction to the classification of elasmobranchs 17 Rekha J. Nair and P.U Zacharia Central Marine Fisheries Research Institute, Kochi-682 018 Introduction eyed, stomachless, deep-sea creatures that possess an upper jaw which is fused to its cranium (unlike in sharks). The term Elasmobranchs or chondrichthyans refers to the The great majority of the commercially important species of group of marine organisms with a skeleton made of cartilage. chondrichthyans are elasmobranchs. The latter are named They include sharks, skates, rays and chimaeras. These for their plated gills which communicate to the exterior by organisms are characterised by and differ from their sister 5–7 openings. In total, there are about 869+ extant species group of bony fishes in the characteristics like cartilaginous of elasmobranchs, with about 400+ of those being sharks skeleton, absence of swim bladders and presence of five and the rest skates and rays. Taxonomy is also perhaps to seven pairs of naked gill slits that are not covered by an infamously known for its constant, yet essential, revisions operculum. The chondrichthyans which are placed in Class of the relationships and identity of different organisms. Elasmobranchii are grouped into two main subdivisions Classification of elasmobranchs certainly does not evade this Holocephalii (Chimaeras or ratfishes and elephant fishes) process, and species are sometimes lumped in with other with three families and approximately 37 species inhabiting species, or renamed, or assigned to different families and deep cool waters; and the Elasmobranchii, which is a large, other taxonomic groupings. It is certain, however, that such diverse group (sharks, skates and rays) with representatives revisions will clarify our view of the taxonomy and phylogeny in all types of environments, from fresh waters to the bottom (evolutionary relationships) of elasmobranchs, leading to a of marine trenches and from polar regions to warm tropical better understanding of how these creatures evolved.
    [Show full text]
  • Function of the Respiratory System - General
    Lesson 27 Lesson Outline: Evolution of Respiratory Mechanisms – Cutaneous Exchange • Evolution of Respiratory Mechanisms - Water Breathers o Origin of pharyngeal slits from corner of mouth o Origin of skeletal support/ origin of jaws o Presence of strainers o Origin of gills o Gill coverings • Form - Water Breathers o Structure of Gills Chondrichthyes Osteichthyes • Function – Water Breathers o Pumping action and path of water flow Chondrichthyes Osteichthyes Objectives: At the end of this lesson you should be able to: • Describe the evolutionary trends seen in respiratory mechanisms in water breathers • Describe the structure of the different types of gills found in water breathers • Describe the pumping mechanisms used to move water over the gills in water breathers References: Chapter 13: pgs 292-313 Reading for Next Lesson: Chapter 13: pgs 292-313 Function of the Respiratory System - General Respiratory Organs Cutaneous Exchange Gas exchange across the skin takes place in many vertebrates in both air and water. All that is required is a good capillary supply, a thin exchange barrier and a moist outer surface. As you will remember from lectures on the integumentary system, this is often in conflict with the other functions of the integument. Cutaneous respiration is utilized most extensively in amphibians but is not uncommon in fish and reptiles. It is not used extensively in birds or mammals, although there are instances where it can play an important role (bats loose 12% of their CO2 this way). For the most part, it: - plays a larger role in smaller animals (some small salamanders are lungless). - requires a moist skin which is thin, has a high capillary density and no thick keratinised outer layer.
    [Show full text]
  • Histological Observation of the External Gills of a Mexican Axolotl (Ambystoma Mexicanum) with Atypical Blood Vessels
    Naturalistae 23: 47-52 (Feb. 2019) © 2019 by Okayama University of Science, PDF downloadable at http://www1.ous.ac.jp/garden/ Original paper Histological observation of the external gills of a Mexican axolotl (Ambystoma mexicanum) with atypical blood vessels Saki YOSHIDA1 and Kazuyuki MEKADA1* Abstract: The external gills of captive Mexican axolotl (Ambystoma mexicanum) sometimes develop atypical blood vessels, the cause of which is unknown. We observed the external gill filaments of an individual animal with dilated blood vessels that formed a semicircle within the filament tissue. The positioning of the swollen blood vessels compressed the adjacent capillaries and connective tissues. Normal external gill filaments in urodelans contain a blood-vessel system with afferent and efferent arterioles that connect to circumvent the outer gill periphery. We infer that the dilated blood vessels in the axolotl originated from these arterioles. I. Introduction et al. 2015, Nowoshilow et al. 2018, Page et al. 2013, Voss et al. 2015). Furthermore, the Mexican The Mexican axolotl (Ambystoma mexicanum) axolotl has gained widespread popularity as a pet is a tailed urodelan amphibian indigenous to (Lang 2013, Reiβ et al. 2015). Lake Xochimilco and Lake Chalco in Mexico Amphibian larvae have either external or (Zambrano et al. 2007). Over the past 50 years, it internal gills (Brunelli et al. 2009). Generally, has been used as a model organism in disciplines urodele larvae have external gills on both sides such as evolution, embryology, and regeneration of the neck until metamorphosis. However, the (Reiβ et al. 2015, Voss et al. 2009). Recently its axolotl does not metamorphose at sexual matu- genome has been sequenced to allow studies of rity, and instead retains its external gills (Bishop comparative genomics, quantitative trait locus 1994).
    [Show full text]
  • Respiratory Disorders of Fish
    This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier’s archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright Author's personal copy Disorders of the Respiratory System in Pet and Ornamental Fish a, b Helen E. Roberts, DVM *, Stephen A. Smith, DVM, PhD KEYWORDS Pet fish Ornamental fish Branchitis Gill Wet mount cytology Hypoxia Respiratory disorders Pathology Living in an aquatic environment where oxygen is in less supply and harder to extract than in a terrestrial one, fish have developed a respiratory system that is much more efficient than terrestrial vertebrates. The gills of fish are a unique organ system and serve several functions including respiration, osmoregulation, excretion of nitroge- nous wastes, and acid-base regulation.1 The gills are the primary site of oxygen exchange in fish and are in intimate contact with the aquatic environment. In most cases, the separation between the water and the tissues of the fish is only a few cell layers thick. Gills are a common target for assault by infectious and noninfectious disease processes.2 Nonlethal diagnostic biopsy of the gills can identify pathologic changes, provide samples for bacterial culture/identification/sensitivity testing, aid in fungal element identification, provide samples for viral testing, and provide parasitic organisms for identification.3–6 This diagnostic test is so important that it should be included as part of every diagnostic workup performed on a fish.
    [Show full text]
  • Book Review: Fishing Into Our Past
    Evolutionary Psychology www.epjournal.net – 2008. 6(2): 365-368 ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ Book Review Fishing into our Past A review of Neil Shubin, Your Inner Fish: A Journey into the 3.5 Billion-Year History of the Human Body. Allen Lane: London, 2008, 229pp, UK£20, ISBN13: 9780713999358 (Hardcover) Robert King, Department of Psychology, Birkbeck College, University of London, UK. Email: [email protected] I am sure that many of us vividly remember the first time we started to get evolutionary psychology. For me it was like coming out of the optician’s with new glasses and realizing that I had been making do with a terribly short-sighted blur for ages. There is a sort of vertigo attendant on appreciating that the self is not just a few decades old or, as the cultural determinists claimed, centuries old. The realization that our selves could be understood only on the scale of millions of years creates dizziness. It is like that first time lying on one’s back staring into the time machine that is the star-filled night sky and it’s hitting you that many of those stars are now long dead. Those in Evolutionary Psychology (EP) are used to the concept of Deep Time. Some new term needs to be invented for what is stressed in Neil Shubin’s Your Inner Fish. Bottomless Time? Unfathomable Time? Shubin invites us to pan back our usual EP scale by three orders of magnitude from the savannah ape and consider ourselves from the perspective of 3.5 billion years. Of course, in doing this, Shubin is taking us back well beyond the “inner fish” of the title, but it is fish that made Shubin famous.
    [Show full text]
  • Morphological Alterations in the External Gills of Some Tadpoles in Response to Ph
    THIEME 142 Original Article Morphological Alterations in the External Gills of Some Tadpoles in Response to pH CaressaMaebhaThabah1 Longjam Merinda Devi1 Rupa Nylla Kynta Hooroo1 Sudip Dey2 1 Developmental Biology Laboratory, Department of Zoology, North- Address for correspondence Caressa Maebha Thabah, PhD in Eastern Hill University, Shillong, Meghalaya, India Zoology, Developmental Biology Laboratory, Department of Zoology, 2 Electron Microscope Laboratory, Sophisticated Analytical Instrument North-Eastern Hill University, Shillong 793022, Meghalaya, India Facility, North-Eastern Hill University, Shillong, Meghalaya, India (e-mail: [email protected]). J Morphol Sci 2018;35:142–152. Abstract Introduction Water pH affects the breeding, hatching, development, locomotion, mortality and habitat distributions of species in nature. The external gills of anuran tadpoles were studied by several authors in relation to abiotic factors. Exposure to low and high pH has been found to adversely affect the different tissues of various organisms. On that consideration, the present investigation was performed with tadpoles of the species Hyla annectans and Euphlyctis cyanophlyctis. Material and Methods The maximum and the minimum pH thresholds were determined prior to the detailed experiments on the effects of pH. The pH that demonstrated 50% mortality was taken as the minimum and maximum pH thresholds. The hatchlings of both the species were then subjected to different pH (based on the minimum and maximum pH thresholds). After 48 hours of exposure, the external gills of the hatchlings were anesthetized and observed under a scanning electron microscope. Keywords Results After 48 hours, clumping, overlapping and curling of the secondary filaments ► Hyla annectans of the external gills and epithelial lesions in response to both acidic and alkaline pH ► Euphlyctis were observed.
    [Show full text]
  • Spiracular Air Breathing in Polypterid Fishes and Its Implications for Aerial
    ARTICLE Received 1 May 2013 | Accepted 27 Nov 2013 | Published 23 Jan 2014 DOI: 10.1038/ncomms4022 Spiracular air breathing in polypterid fishes and its implications for aerial respiration in stem tetrapods Jeffrey B. Graham1, Nicholas C. Wegner1,2, Lauren A. Miller1, Corey J. Jew1, N Chin Lai1,3, Rachel M. Berquist4, Lawrence R. Frank4 & John A. Long5,6 The polypterids (bichirs and ropefish) are extant basal actinopterygian (ray-finned) fishes that breathe air and share similarities with extant lobe-finned sarcopterygians (lungfishes and tetrapods) in lung structure. They are also similar to some fossil sarcopterygians, including stem tetrapods, in having large paired openings (spiracles) on top of their head. The role of spiracles in polypterid respiration has been unclear, with early reports suggesting that polypterids could inhale air through the spiracles, while later reports have largely dismissed such observations. Here we resolve the 100-year-old mystery by presenting structural, behavioural, video, kinematic and pressure data that show spiracle-mediated aspiration accounts for up to 93% of all air breaths in four species of Polypterus. Similarity in the size and position of polypterid spiracles with those of some stem tetrapods suggests that spiracular air breathing may have been an important respiratory strategy during the fish-tetrapod transition from water to land. 1 Marine Biology Research Division, Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, USA. 2 Fisheries Resource Division, Southwest Fisheries Science Center, NOAA Fisheries, La Jolla, California 92037, USA. 3 VA San Diego Healthcare System, San Diego, California 92161, USA.
    [Show full text]
  • External Gills and Adaptive Embryo Behavior Facilitate Synchronous Development and Hatching Plasticity Under Respiratory Constraint
    3627 The Journal of Experimental Biology 211, 3627-3635 Published by The Company of Biologists 2008 doi:10.1242/jeb.020958 External gills and adaptive embryo behavior facilitate synchronous development and hatching plasticity under respiratory constraint Jessica R. Rogge and Karen M. Warkentin* Department of Biology, Boston University, Boston, MA 02215, USA 'Author for correspondence (e-mail: [email protected]) Accepted 22 September 2008 SUMMARY Plasticity in hatching timing allows embryos to balance egg- and larval-stage risks, and depends on the ability of hatching- competent embryos to continue developing in the egg. Hypoxia can slow development, kill embryos and induce premature hatching. For terrestrial eggs of red-eyed treefrogs, the embryonic period can extend ~50% longer than development to hatching competence, and development is synchronous across perivitelline oxygen levels (Po2) ranging from 0.5-16.5 kPa. Embryos maintain large external gills until hatching, then gills regress rapidly. We assessed the respiratory value of external gills using gill manipulations and closed-system respirometry. Embryos without external gills were oxygen limited in air and hatched at an external Po2 of 17kPa, whereas embryos with gills regulated their metabolism and remained in the egg at substantially lower Po2. By contrast, tadpoles gained no respiratory benefit from external gills. We videotaped behavior and manipulated embryos to test if they position gills near the air-exposed portion of the egg surface, where PQ2 is highest. Active embryos remained stationary for minutes in gills-at-surface positions. After manipulations and spontaneous movements that positioned gills in the 02-poor region of the egg, however, they returned their gills to the air-exposed surface within seconds.
    [Show full text]
  • Efficiency and Selectivity of Gill Nets for Assessing Fish Community
    North American Journal of Fisheries Management 25:1315±1320, 2005 q Copyright by the American Fisheries Society 2005 [Management Brief] DOI: 10.1577/M04-104.1 Ef®ciency and Selectivity of Gill Nets for Assessing Fish Community Composition of Large Rivers DAVID G. ARGENT* AND WILLIAM G. KIMMEL Biological and Environmental Sciences Department, California University of Pennsylvania, 250 University Avenue, California, Pennsylvania 15419, USA Abstract.ÐTo evaluate the ef®ciency and selectivity netting must be understood to be used to sample of gill netting for assessing ®sh biodiversity in the upper target ®sh communities (TFCs) as part of a tem- Ohio River system, we compared the ef®ciency of ®ve poral monitoring program. gill-net types for sampling large-bodied ®shes (adult to- tal length greater than 250 mm) during fall 2001 and Most existing studies focus on comparisons spring and fall 2002. Mesh sizes ranged from 3.8 cm to among gear types (e.g., gill netting versus elec- 14 cm (bar measure). We set the gill nets in selected tro®shing) rather than ef®ciency within a speci®c pools of the Allegheny, Monongahela, and Ohio rivers gill-net mesh size (Elliott and Fletcher 2001; Col- 186 times over three seasons for a total of 1,644 net- vin 2002) or on one target species or several target hours. Nets were attached to a variety of structures, in- species with the objective of developing selectivity cluding trees and rootwads, bridge pylons, lock and dam chambers, and channel marker buoys. Nets were ®shed curves (Berst 1961; Hamley 1975). Unfortunately, from late evening to ®rst light, and all ®sh captured were these studies provide little information to discern identi®ed, enumerated, and released.
    [Show full text]
  • Introduction to Phylum Chordata
    Unifying Themes 1. Chordate evolution is a history of innovations that is built upon major invertebrate traits •bilateral symmetry •cephalization •segmentation •coelom or "gut" tube 2. Chordate evolution is marked by physical and behavioral specializations • For example the forelimb of mammals has a wide range of structural variation, specialized by natural selection 3. Evolutionary innovations and specializations led to adaptive radiations - the development of a variety of forms from a single ancestral group Characteristics of the Chordates 1. Notochord 2. dorsal hollow nerve cord 3. pharyngeal gill slits 4. postanal tail 5. endostyle Characteristics of the Chordates Notochord •stiff, flexible rod, provides internal support • Remains throughout the life of most invertebrate chordates • only in the embryos of vertebrate chordates Characteristics of the Chordates cont. Dorsal Hollow Nerve Cord (Spinal Cord) •fluid-filled tube of nerve tissue, runs the length of the animal, just dorsal to the notochord • Present in chordates throughout embryonic and adult life Characteristics of the Chordates cont. Pharyngeal gill slits • Pairs of opening through the pharynx • Invertebrate chordates use them to filter food •In fishes the gill sits develop into true gills • In reptiles, birds, and mammals the gill slits are vestiges (occurring only in the embryo) Characteristics of the Chordates cont. Endostyle • mucous secreting structure found in the pharynx floor (traps small food particles) Characteristics of the Chordates cont. Postanal Tail • works with muscles (myomeres) & notochord to provide motility & stability • Aids in propulsion in nonvertebrates & fish but vestigial in later lineages SubPhylum Urochordata Ex: tunicates or sea squirts • Sessile as adults, but motile during the larval stages • Possess all 5 chordate characteristics as larvae • Settle head first on hard substrates and undergo a dramatic metamorphosis • tail, notochord, muscle segments, and nerve cord disappear SubPhylum Urochordata cont.
    [Show full text]