DOCSLIB.ORG

West African Lungfish a Living Fossil’S Biological and Behavioral Adaptations

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
West African Lungfish a Living Fossil’S Biological and Behavioral Adaptations VideoMedia Spotlight West African Lungfish A living fossil’s biological and behavioral adaptations For the complete video with media resources, visit: http://education.nationalgeographic.org/media/west-african-lungfish/ Funder West African lungfish are prehistoric animals. They have survived unchanged for so long (nearly 400 million years) that they are sometimes nicknamed “living fossils.” West African lungfish have remarkable adaptations that have helped them survive: a primitive lung and the ability to survive in a state of estivation, which is similar to hibernation. A lungfish’s lung is a biological adaptation. A biological adaptation is a physical change in an organism that develops over time. Like all fish, lungfish have organs known as gills to extract oxygen from water. The biological adaptation of the lung allows lungfish to also extract oxygen from the air. A lungfish’s estivation also involves a number of biological adaptations, including the excretion of a mucus “cocoon” and digestion of the fish’s own muscle tissue to obtain nutrients. A lungfish’s estivation also includes a behavioral adaptation. A behavioral adaptation describes a way an organism acts. Prior to estivation, lungfish furiously burrow into the muddy ground. The behavioral adaptation of burrowing allows lungfish to create a protected habitat where they can survive during a long period of dormancy. Watch this video, from the Nat Geo WILD series “Destination Wild,” and use our glossary to help answer questions in the Questions tab. Learn more about these fascinating fish with our Fast Facts. Questions How has the West African lungfish’s primitive lung helped the species survive for more than 300 million years? 1 of 5 During the dry season, the West African lungfish can breathe (extract oxygen from the air) as lakes and ponds turn to mud and cracked earth. As the rainy season restores the lungfish’s aquatic habitat, it can rely mostly on its gills to extract oxygen from the water. How has the West African lungfish’s estivation behavior helped the species survive for more than 300 million years? The lungfish creates a mucus “cocoon” prior to estivation. The cocoon traps moisture and lets in air as the fish estivates. As the metabolism of the lungfish slows, it digests muscle in its tail to consume nutrients and stay alive. The burrowing, mucus cocoon, and self-digestion allow the lungfish to survive years beneath the dry landscape. Fast Facts The West African lungfish digs its burrow using its mouth. It chews through the moist earth, excreting the mud through its gills. West African lungfish have a very slow metabolism. This means they are much less active than other fish, and often rest at the bottom of a lakebed or riverbed. In fact, West African lungfish are so inactive that many aquarium owners mistakenly think their fish is dead! The largest specimen of West African lungfish was a meter (3.3 feet) long and weighed a whopping 4 kilograms (nearly 9 pounds). The West African lungfish is an omnivore. It feeds on everything from frogs, fish, and mollusks to tree roots and seeds. Although larger fish and mammals may prey on juvenile lungfish, the adult lungfish has no major predators. There are four species of African lungfish. (The one in the Destination Wild video is the West African lungfish, found in freshwater habitats throughout sub-Saharan Africa.) Other species of lungfish are indigenous to Australia and South America. Vocabulary Part of Term Definition Speech a modification of an organism or its parts that makes it more fit for existence. adaptation noun An adaptation is passed from generation to generation. air noun layer of gases surrounding Earth. aquatic adjective having to do with water. behavioral way an organism acts in order to survive or thrive in its environment. adaptation noun 2 of 5 Part of Term Definition Speech biological physical change in an organism that results over time in reaction to its adaptation noun environment. burrow verb to dig a small hole or tunnel. silky covering spun by silkworms and other insect larvae in which they live and cocoon noun develop during the pupal stage. consume verb to use up. process in breaking down ingested food into easily absorbed and assimilated digestion noun substances by the action of enzymes and other agents. dormant adjective state of minimal growth or activity. dry season noun time of year with little precipitation. earth noun soil or dirt. estivation inactive state resembling deep sleep, in which some animals living in hot noun climates pass the summer. excrete verb to discharge a substance from the body. extract verb to pull out. furious adjective having a wild or violent passion. gills plural respiratory organs that draw oxygen from water and into the bloodstream. noun environment where an organism lives throughout the year or for shorter habitat noun periods of time. hibernationnoun condition, similar to sleep, in which some animals spend the winter. lake noun body of water surrounded by land. landscape noun the geographic features of a region. organism that is a living example of an otherwise extinct group or that has living fossil noun remained virtually unchanged in structure and function over a long period of time. lung noun organ in an animal that is necessary for breathing. metabolismnoun chemical changes in living cells by which energy is provided for vital processes. 3 of 5 Part of Term Definition Speech moisture noun wetness. mucus adjective,slimy, fluid secretion of some animals. noun mud noun wet soil. muscle noun tissue found in animals that expands and contracts, allowing movement. nutrient noun substance an organism needs for energy, growth, and life. obtain verb to get or take possession of. organism noun living or once-living thing. physical adjective having to do with the body. pond noun small body of water surrounded by land. prehistoric adjective period of time that occurred before the invention of written records. prepare verb to assemble or get ready for something. primitive adjective simple or crude. prior adjective before or ahead of. protect verb to take action to prevent injury or attack. rainy time of year when most of the rain in a region falls. season noun remarkable adjective unusual and dramatic. respiration noun breathing. restore verb to renew or bring back to an earlier position or state of health. tissue noun cells that form a specific function in a living organism. Images Primitive Fishes: Lungfishes Video BBC: The Lung Fish Websites Oregon Zoo: African Lungfish 4 of 5 © 1996–2016 National Geographic Society. All rights reserved. 5 of 5.
Load more

Recommended publications
  • RESPIRATORY CONTROL in the LUNGFISH, NEOCERATODUS FORSTERI (KREFT) KJELL JOHANSEN, CLAUDE LENFANT and GORDON C
    Comp. Biochem. Physiol., 1967, Vol. 20, pp. 835-854 RESPIRATORY CONTROL IN THE LUNGFISH, NEOCERATODUS FORSTERI (KREFT) KJELL JOHANSEN, CLAUDE LENFANT and GORDON C. GRIGG Abstract-1. Respiratory control has been studied in the lungfish, Neoceratodus forsteri by measuring ventilation (Ve), oxygen uptake (VO2), per cent O2 extraction from water, breathing rates of branchial and aerial respiration and changes in blood gas and pulmonary gas composition during exposure to hypoxia and hypercarbia. 2. Hypoxic water represents a strong stimulus for compensatory increase in both branchial and aerial respiration. Water ventilation increases by a factor of 3 or 4 primarily as a result of increased depth of breathing. 3. The ventilation perfusion ratio decreased during hypoxia because of a marked increase in cardiac output. Hypoxia also increased the fraction of total blood flow perfusing the lung. Injection of nitrogen into the lung evoked no compensatory changes. 4. It is concluded that the chemoreceptors eliciting the compensatory changes are located on the external side facing the ambient water or in the efferent branchial blood vessels. 5. Elevated pCO2 in the ambient water depressed the branchial respiration but stimulated aerial respiration. 6. It is suggested that the primary regulatory effect of the response to increased ambient pCO2 is to prevent CO2 from entering the animal, while the secondary stimulation of air breathing is caused by hypoxic stimulation of chemoreceptors located in the efferent branchial vessels. INTRODUCTION I t i s generally accepted that vertebrates acquired functional lungs before they possessed a locomotor apparatus for invasion of a terrestrial environment. Shortage of oxygen in the environment is thought to have been the primary driving force behind the development of auxiliary air breathing.
    [Show full text]
  • Horodysky Throws Light on Fish Vision
    3 Horodysky Throws Light on Fish Vision Andrij Horodysky’s research can be The research is part of an emerg- Horodysky also benefits summed up in a simple saying—what ing field called “visual ecology” that from collaborations with Char- you see is what you get. promises to throw new light on animal ter captains like Steve Wray, Horodysky, a VIMS graduate behavior and the interactions between who provide him with the fish student working with faculty members predators and prey. Horodysky and his he needs for his experiments. Drs. Rich Brill, Rob Latour, and Jack advisors are pioneers in applying this Horodysky’s preliminary Musick, is using electroretinography—a field to Bay fishes. results provide basic insight technique first developed for studying The researchers are focusing their into how Bay fishes see the human vision—to explore how fishes initial studies on recreationally impor- world. The results show that see the underwater world of Chesapeake tant Bay species such as striped bass, some species, like striped bass, Bay. weakfish, croaker, and drum. This re- are adapted to see large, swiftly Brill, an internationally recognized flects the source of their funding, which moving prey in daylight. Oth- fish physiologist who heads NOAA’s comes from the Recreational Fishing ers, like weakfish, are adapted Cooperative Marine Education and Advisory Board of the Virginia Marine to see small, sluggish prey at Research (CMER) program at VIMS, Resources Commission. The Board uses night. has recently turned his attention to the money from Virginia’s saltwater fishing He is also comparing the sensory world of fish and other marine license to fund projects that improve the types of prey that fishes are organisms.
    [Show full text]
  • Sight for Sore Eyes: Ancient Fish See Colour 19 September 2005
    Sight for sore eyes: ancient fish see colour 19 September 2005 The Australian lungfish - one of the world’s oldest pigments, are bigger in lungfish than for any other fishes and related to our ancient ancestors - may animal with a backbone. This probably makes them have been viewing rivers in technicolour long more sensitive to light. before dinosaurs roamed the Earth. “We keep discovering ways in which these animals Recent work by postgraduate student Helena are quite different from other fish,” Helena says. Bailes at the University of Queensland Australia, “Their eyes seem designed to optimise both has found these unusual fish have genes for five sensitivity and colour vision with large cells different forms of visual pigment in their eyes. containing different visual pigments.” Humans only have three. She now is hoping that behavioural research can Helena is one of 13 early-career researchers who find out how these fish are using their eyes for have presented their work to the public and the colour vision in the wild. media for the first time as part of the national program Fresh Science. “We may then learn what Queensland rivers look like to some of their oldest inhabitants, before those Night and day (colour) vision are controlled by inhabitants are wiped out,” Bailes says. different light sensing cells known respectively as rods and cones. Humans have a single type of rod and three types of cone, each containing a different pigment gene tuned to red, green and blue wavelengths. Lungfish possess two additional pigments that were lost in mammals, Bailes says.
    [Show full text]
  • Should I Eat the Fish I Catch?
    EPA 823-F-14-002 For More Information October 2014 Introduction What can I do to reduce my health risks from eating fish containing chemical For more information about reducing your Fish are an important part of a healthy diet. pollutants? health risks from eating fish that contain chemi- Office of Science and Technology (4305T) They are a lean, low-calorie source of protein. cal pollutants, contact your local or state health Some sport fish caught in the nation’s lakes, Following these steps can reduce your health or environmental protection department. You rivers, oceans, and estuaries, however, may risks from eating fish containing chemical can find links to state fish advisory programs Should I Eat the contain chemicals that could pose health risks if pollutants. The rest of the brochure explains and your state’s fish advisory program contact these fish are eaten in large amounts. these recommendations in more detail. on the National Fish Advisory Program website Fish I Catch? at: http://water.epa.gov/scitech/swguidance/fish- The purpose of this brochure is not to 1. Look for warning signs or call your shellfish/fishadvisories/index.cfm. discourage you from eating fish. It is intended local or state environmental health as a guide to help you select and prepare fish department. Contact them before you You may also contact: that are low in chemical pollutants. By following fish to see if any advisories are posted in these recommendations, you and your family areas where you want to fish. U.S. Environmental Protection Agency can continue to enjoy the benefits of eating fish.
    [Show full text]
  • Neopterygian Fish with Secondary Sexual Characteristics Found from the Middle Triassic of China 18 February 2016
    Neopterygian fish with secondary sexual characteristics found from the Middle Triassic of China 18 February 2016 Sciences, and his collaborator reported a new sexually dimorphic primitive neopterygian fish, Venusichthys comptus, based on 30 exceptionally well-preserved specimens from the Middle Triassic (Pelsonian, Anisian) Luoping Lagerstätte of eastern Yunnan, China. The discovery represents the oldest known secondary sexual characteristics in Neopterygii, and provides an important addition for understanding the behavior, reproduction, and early diversification of Neopterygii. The Luoping Lagerstätte fossil beds are composed of thinly laminated micritic limestone alternating with silty limestone, indicating a semi-enclosed intraplatform depositional environment. This new species has a blunt snout, an elongate and fusiform body, and an almost homocercal caudal fin with a forked profile. All 30 specimens represent a small- Fig.1 Female specimen of Venusichthys comptus before sized primitive neopterygian with a standard length (a) and after coated with ammonium chloride. Credit: XU ranging from 25 to 38 mm. Guanghui Secondary sexual characteristics are features that appear at sexual maturity and distinguish the two sexes of a species. Studies of secondary sexual characteristics in a species are vital for fully understanding its behavior, reproduction, and evolution. Secondary sexual characteristics are easily observed and studied in living animals, but the situation is rather more complicated in extinct animals, primarily due to inadequacies of sample size or the fragmentary nature of fossil remains. Neopterygii are the most diverse group of extant ray-finned fishes, which underwent a rapid radiation in the aftermath of end-Permian mass extinction. In a paper published online 23 January in the journal Science Bulletin, Dr.
    [Show full text]
  • BMC Ecology Biomed Central
    BMC Ecology BioMed Central Research article Open Access Visual ecology of the Australian lungfish (Neoceratodus forsteri) Nathan S Hart*1, Helena J Bailes1,2, Misha Vorobyev1,3, N Justin Marshall1 and Shaun P Collin1 Address: 1School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia, 2Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK and 3Department of Optometry and Vision Science, The University of Auckland, Private Bag 92019, Auckland, New Zealand Email: Nathan S Hart* - [email protected]; Helena J Bailes - [email protected]; Misha Vorobyev - [email protected]; N Justin Marshall - [email protected]; Shaun P Collin - [email protected] * Corresponding author Published: 18 December 2008 Received: 27 August 2008 Accepted: 18 December 2008 BMC Ecology 2008, 8:21 doi:10.1186/1472-6785-8-21 This article is available from: http://www.biomedcentral.com/1472-6785/8/21 © 2008 Hart et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: The transition from water to land was a key event in the evolution of vertebrates that occurred over a period of 15–20 million years towards the end of the Devonian. Tetrapods, including all land-living vertebrates, are thought to have evolved from lobe-finned (sarcopterygian) fish that developed adaptations for an amphibious existence.
    [Show full text]
  • Tetrapod Limb and Sarcopterygian Fin Regeneration Share a Core Genetic
    ARTICLE Received 28 Apr 2016 | Accepted 27 Sep 2016 | Published 2 Nov 2016 DOI: 10.1038/ncomms13364 OPEN Tetrapod limb and sarcopterygian fin regeneration share a core genetic programme Acacio F. Nogueira1,*, Carinne M. Costa1,*, Jamily Lorena1, Rodrigo N. Moreira1, Gabriela N. Frota-Lima1, Carolina Furtado2, Mark Robinson3, Chris T. Amemiya3,4, Sylvain Darnet1 & Igor Schneider1 Salamanders are the only living tetrapods capable of fully regenerating limbs. The discovery of salamander lineage-specific genes (LSGs) expressed during limb regeneration suggests that this capacity is a salamander novelty. Conversely, recent paleontological evidence supports a deeper evolutionary origin, before the occurrence of salamanders in the fossil record. Here we show that lungfishes, the sister group of tetrapods, regenerate their fins through morphological steps equivalent to those seen in salamanders. Lungfish de novo transcriptome assembly and differential gene expression analysis reveal notable parallels between lungfish and salamander appendage regeneration, including strong downregulation of muscle proteins and upregulation of oncogenes, developmental genes and lungfish LSGs. MARCKS-like protein (MLP), recently discovered as a regeneration-initiating molecule in salamander, is likewise upregulated during early stages of lungfish fin regeneration. Taken together, our results lend strong support for the hypothesis that tetrapods inherited a bona fide limb regeneration programme concomitant with the fin-to-limb transition. 1 Instituto de Cieˆncias Biolo´gicas, Universidade Federal do Para´, Rua Augusto Correa, 01, Bele´m66075-110,Brazil.2 Unidade Genoˆmica, Programa de Gene´tica, Instituto Nacional do Caˆncer, Rio de Janeiro 20230-240, Brazil. 3 Benaroya Research Institute at Virginia Mason, 1201 Ninth Avenue, Seattle, Washington 98101, USA. 4 Department of Biology, University of Washington 106 Kincaid, Seattle, Washington 98195, USA.
    [Show full text]
  • Fishery Science – Biology & Ecology
    Fishery Science – Biology & Ecology How Fish Reproduce Illustration of a generic fish life cycle. Source: Zebrafish Information Server, University of South Carolina (http://zebra.sc.edu/smell/nitin/nitin.html) Reproduction is an essential component of life, and there are a diverse number of reproductive strategies in fishes throughout the world. In marine fishes, there are three basic reproductive strategies that can be used to classify fish. The most common reproductive strategy in marine ecosystems is oviparity. Approximately 90% of bony and 43% of cartilaginous fish are oviparous (See Types of Fish). In oviparous fish, females spawn eggs into the water column, which are then fertilized by males. For most oviparous fish, the eggs take less energy to produce so the females release large quantities of eggs. For example, a female Ocean Sunfish is able to produce 300 million eggs over a spawning cycle. The eggs that become fertilized in oviparous fish may spend long periods of time in the water column as larvae before settling out as juveniles. An advantage of oviparity is the number of eggs produced, because it is likely some of the offspring will survive. However, the offspring are at a disadvantage because they must go through a larval stage in which their location is directed by oceans currents. During the larval stage, the larvae act as primary consumers (See How Fish Eat) in the food web where they must not only obtain food but also avoid predation. Another disadvantage is that the larvae might not find suitable habitat when they settle out of the ~ Voices of the Bay ~ [email protected] ~ http://sanctuaries.noaa.gov/education/voicesofthebay.html ~ (Nov 2011) Fishery Science – Biology & Ecology water column.
    [Show full text]
  • Giant Fossil Coelacanths from the Late Cretaceous of the Eastern
    ^rfij^i^v^^™, - » v ' - - 4 j/ N ^P"" ,- V ^™ V- -*^ >•;:-* ' ^ * -r;' David R. Schwimmer, Geologist, Columbus State University Introduction In Autumn, 1987, a sizeable mass of fossil bone was discovered by amateur collectors in the bed of a small creek in eastern Alabama. The bone-bearing rock, some 300 kg in weight, was collected by a party led by G. Dent Williams and transferred to the paleontology laboratory at Columbus State University. Williams prepared most of the material using air percussion tools, and I further cleared some bones with acetic acid. A mandible (lower jaw bone) of 502 mm length was the first bone prepared from the material. It strangely lacked evidence of both teeth and tooth sockets, and it was covered medially with coarse denticulation resembling #40 grit sandpaper. The jawbone conformed with no recognizable North American Late Cretaceous fish or four-legged animal, and, given the large size of the mandible, my initial search for an identification ranged from ankylosaurid dinosaurs, to mosasaurs, to the larger contemporary fish, such as Xiphactinus. Nothing known in the Late Cretaceous of North America matched the mandible nor any other bone which was subsequently prepared from this matrix. J.D. Stewart of the L.A. County Museum was prior fossil record of a North American coelacanth is concurrently studying fossils of small marine Diplurus newarki, from freshwater deposits of earliest coelacanths from the Late Cretaceous of western Kansas, Jurassic age (ca. 205 Myr.: Schaeffer, 1941, 1952). USA (which were also a new discovery at the time: see Forey (1981) and Maisey (1991) recognized two sub- Stewart et al., 1991).
    [Show full text]
  • Explore a Fish Lesson Plan
    Grade Level 4 - 12 EXPLORE A FISH Duration FISH DISSECTION 1 - 1 ½ hours Subject/Subject Area Focus Overview Science, language arts; Students will examine the external and internal anatomy of various fish Analysis, application, species. They will note similarities and differences. Students will then communication, use their observations to make inferences about the relationships among comparing similarities and them. differences, description, discussion, drawing, small Background information group work, using time This activity gives students first-hand experience exploring the and space, writing. adaptations which allow fish to function in their environment. Students look at both form and function of different systems to help understand Materials how specific adaptations assist organisms in adapting to their For each pair (or group) of environment. How do fish move through the water and keep their vertical students: position within the water? Students can make comparisons between their • Whole body fresh fish own anatomy and the anatomy of a fish. • Dissecting trays or thick pads of newspaper It is important for students to understand the purpose of this activity • Scissors or Scalpel is to study the internal and external anatomy of a fish. It requires (Most cuts can be concentration, listening skills and being able to follow directions. All made with a pair of students should be given the option of not participating in the activity classroom scissors) and be allowed an alternate activity. You may want to do a practice run on • Probe (A large partially your own. straightened paper clip works well) You can either do this activity as a teacher-led class discussion or break • Forceps (A nice tool but the students into cooperative learning groups and give each group: a fish, not necessary) “Explore a Fish” worksheet, dissection and anatomy sheet, newspaper • Paper towels and and something to cut the fish with.
    [Show full text]
  • Fish Anatomy
    Fish Anatomy Objectives: become acquainted with the general external and internal structures of fishes, and how they vary functionally and taxonomically Head mouth mouth position – superior, terminal, sub-terminal, inferior teeth types and locations barbels, tubercules – what are their positions and uses? sensory pores nares Body shapes – which taxa have each, what are the advantages of each type? fusiform sagittaform aguilliform compressiform depressiform filiform Fins – what are each used for? how does their presence or location vary among taxa? paired fins: pelvic pectoral anal single fins: dorsal - one or two; rarely three, as in cod family (median) caudal - adipose spines vs. rays Internal organs GI tract, reproductive organs, excretory system including kidneys, liver gas bladder (present or absent, sealed or unsealed, connected or not to other organs) Body musculature (more on these later when we talk about swimming) hypaxial muscles epaxial muscles myomeres Skin and scales presence, absence, or partial covering of scales functions of scales types of scales: placoid, ganoid, cycloid, ctenoid, scutes skin pigmentation: melanophores Anatomy, cont. Terms/structures you should know: Osteology Skull branchial arches; gill rakers premaxilla, maxilla, dentary operculum: opercle, subopercle, preopercle, interopercle bones which have teeth attached, including pharyngeal teeth otoliths Vetebral column neural spine, neural arch, neural canal centrum zygopophysis, basapophysis hemal spine, hemal arch (not always present?), hemal canal ribs (dorsal - epipleurals, and ventral - pleurals) Caudal skeleton urostyle hypurals epurals Appendicular skeleton pterygiophores lepidotrichia ceratotrichia pectoral girdle - cleithrum pelvic girdle .
    [Show full text]
  • Bichir External Gills Arise Via Heterochronic Shift That Accelerates
    RESEARCH ARTICLE Bichir external gills arise via heterochronic shift that accelerates hyoid arch development Jan Stundl1,2, Anna Pospisilova1, David Jandzik1,3, Peter Fabian1†, Barbora Dobiasova1‡, Martin Minarik1§, Brian D Metscher4, Vladimir Soukup1*, Robert Cerny1* 1Department of Zoology, Faculty of Science, Charles University in Prague, Prague, Czech Republic; 2National Museum, Prague, Czech Republic; 3Department of Zoology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovakia; 4Department of Theoretical Biology, University of Vienna, Vienna, Austria *For correspondence: Abstract In most vertebrates, pharyngeal arches form in a stereotypic anterior-to-posterior [email protected] progression. To gain insight into the mechanisms underlying evolutionary changes in pharyngeal (VS); arch development, here we investigate embryos and larvae of bichirs. Bichirs represent the earliest [email protected] (RC) diverged living group of ray-finned fishes, and possess intriguing traits otherwise typical for lobe- Present address: †Eli and Edythe finned fishes such as ventral paired lungs and larval external gills. In bichir embryos, we find that Broad CIRM Center for the anteroposterior way of formation of cranial segments is modified by the unique acceleration of Regenerative Medicine and Stem the entire hyoid arch segment, with earlier and orchestrated development of the endodermal, Cell Research, University of mesodermal, and neural crest tissues. This major heterochronic shift in the anteroposterior Southern California, Los Angeles, developmental sequence enables early appearance of the external gills that represent key ‡ United States; The Prague breathing organs of bichir free-living embryos and early larvae. Bichirs thus stay as unique models Zoological Garden, Prague, for understanding developmental mechanisms facilitating increased breathing capacity.
    [Show full text]