Aquatic Animals and Homeostasis Quiz
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Questions and Answers

Which of the following statements about gas exchange in aquatic animals is accurate?

  • Aquatic environments provide unlimited oxygen resources.
  • Gills are less efficient than lungs for oxygen extraction.
  • Water has a low oxygen content compared to air. (correct)
  • Aquatic animals have higher oxygen content in water than in air.

    • What is the primary challenge associated with homeostasis in aquatic environments?

  • Excessive heat retention.
  • Dehydration due to high temperatures.
  • Maintaining salt balance in the presence of lower oxygen.
  • Excess salt in the diet for marine tetrapods. (correct)

    • How do aquatic endotherms maintain their body temperature?

  • They rely purely on behavioral adaptation.
  • They do not require any insulative adaptations.
  • They use blubber and waterproof pelage for insulation. (correct)
  • They decrease metabolic activity to conserve heat.

    • Which mechanism allows aquatic animals to maintain a gradient for efficient gas exchange?

    <p>Counter-current heat exchange.</p> Signup and view all the answers

    What distinguishes an endoskeleton from an exoskeleton?

    <p>Endoskeletons are made primarily of collagen.</p> Signup and view all the answers

    How do the limbs of larger animals need to grow to support their body weight?

    <p>Allometrically to increase thickness with size.</p> Signup and view all the answers

    What is a common trait of hydrostatic skeletons?

    <p>They consist of muscle layers surrounding a fluid-filled cavity.</p> Signup and view all the answers

    What factor enhances the challenge of swimming in water for smaller animals?

    <p>Higher viscosity of water.</p> Signup and view all the answers

    Why are aquatic animals generally larger than terrestrial animals?

    <p>Water provides better support, reducing stress on the body.</p> Signup and view all the answers

    What is a critical reason for the use of counter-current heat exchange in marine mammals?

    <p>To retain heat by maintaining a thermal gradient.</p> Signup and view all the answers

    Which of the following is a function of an endoskeleton?

    <p>Transmitting compressive stress effectively.</p> Signup and view all the answers

    What adaptation allows marine birds and reptiles to deal with excess salt?

    <p>Excreting excess salt through specialized glands.</p> Signup and view all the answers

    Which adaptation helps animals in aquatic environments regulate their body temperature?

    <p>Counter-current heat exchange and insulation via blubber or fur.</p> Signup and view all the answers

    What structure supports the robust locomotion required for larger terrestrial animals?

    <p>Endoskeletons that are rigid yet pliable.</p> Signup and view all the answers

    Which attribute of terrestrial environments affects animal locomotion primarily due to gravitational forces?

    <p>Gravity</p> Signup and view all the answers

    What adaptation helps terrestrial animals to limit water loss through their outer layer?

    <p>Keratin and wax</p> Signup and view all the answers

    In which body part do terrestrial mammals primarily carry out water conservation during excretion?

    <p>Kidneys</p> Signup and view all the answers

    What is the function of the Loop of Henle in mammals?

    <p>Water conservation</p> Signup and view all the answers

    What mechanism allows insects to minimize water loss through their respiratory system?

    <p>Spiracles and tracheal system</p> Signup and view all the answers

    What physiological process do terrestrial tardigrades undergo to survive desiccation?

    <p>Cryptobiosis</p> Signup and view all the answers

    How do terrestrial animals primarily cope with the absence of water for fertilization?

    <p>Internal fertilization</p> Signup and view all the answers

    What is a distinct feature of the tracheal system in insects compared to lungs in vertebrates?

    <p>Direct delivery of air to tissues</p> Signup and view all the answers

    Which type of animals primarily excrete nitrogenous waste as uric acid?

    <p>Reptiles and birds</p> Signup and view all the answers

    Which term describes the prolonged period of dormancy in response to heat and drought observed in some terrestrial species?

    <p>Aestivation</p> Signup and view all the answers

    What physiological adaptation primarily aids in gas exchange for terrestrial animals with internalized lungs?

    <p>Moist internal surfaces</p> Signup and view all the answers

    What major disadvantage do terrestrial animals face in breathing air compared to aquatic organisms?

    <p>Evaporative water loss</p> Signup and view all the answers

    In terrestrial animals, what is a consequence of high surface area to volume ratio?

    <p>Higher risk of desiccation</p> Signup and view all the answers

    What evolutionary strategy do some rotifers adopt in stressed environments to ensure survival?

    <p>Sexual reproduction for genetic variability</p> Signup and view all the answers

    What is a primary function of thermoregulation in animals?

    <p>To maintain optimal performance in biochemical processes</p> Signup and view all the answers

    Which method of heat exchange is characterized by direct contact between two objects?

    <p>Conduction</p> Signup and view all the answers

    Endotherms maintain their body temperature through which of the following?

    <p>Production of sufficient metabolic heat</p> Signup and view all the answers

    How do ectothermic animals primarily regulate their body temperature?

    <p>By exchanging heat with the environment</p> Signup and view all the answers

    What mechanism allows cold-climate terrestrial endotherms to conserve heat?

    <p>Countercurrent heat exchange</p> Signup and view all the answers

    Which term describes the condition when an organism allows its body temperature to change significantly?

    <p>Heterothermy</p> Signup and view all the answers

    In insects, what adaptation allows bees to maintain a higher constant thoracic temperature during flight?

    <p>Heterothermic endothermy</p> Signup and view all the answers

    What is the primary advantage of the freeze tolerance strategy in some ectotherms?

    <p>It enables survival in freezing temperatures without damage</p> Signup and view all the answers

    What common feature characterizes both torpor and hibernation?

    <p>A decrease in body temperature and metabolism</p> Signup and view all the answers

    The process of heat transfer through a fluid or gas moving over a surface is called?

    <p>Convection</p> Signup and view all the answers

    Which factor could lead to enzyme denaturation at higher temperatures?

    <p>Change in active site shape</p> Signup and view all the answers

    What happens to performance in ectotherms with environmental temperature changes?

    <p>Performance declines</p> Signup and view all the answers

    What is a key characteristic of ectothermic animals regarding metabolic costs?

    <p>Lower metabolic costs due to dependence on environmental temperatures</p> Signup and view all the answers

    What is one of the main challenges terrestrial animals face compared to those in aquatic environments?

    <p>Maintaining water balance</p> Signup and view all the answers

    Which adaptation helps terrestrial animals reduce water loss from their body surfaces?

    <p>Thicker skin layers</p> Signup and view all the answers

    What physiological feature aids mammals in conserving water during excretion?

    <p>Loop of Henle</p> Signup and view all the answers

    What is a primary mode of gas exchange utilized by terrestrial insects?

    <p>Tracheal system</p> Signup and view all the answers

    How do terrestrial tardigrades cope with extreme environmental conditions?

    <p>Cryptobiosis</p> Signup and view all the answers

    Which nitrogenous waste do reptiles, birds, and insects primarily excrete to conserve water?

    <p>Uric acid</p> Signup and view all the answers

    What adaptation allows animals to cope with desiccation during dry conditions?

    <p>Burrowing behavior</p> Signup and view all the answers

    Which reproduction strategy is employed by rotifers in stressed environments?

    <p>Sexual reproduction</p> Signup and view all the answers

    What is the main benefit of air as a respiratory medium for terrestrial animals?

    <p>Ease of gas diffusion</p> Signup and view all the answers

    What is a significant factor that affects locomotion in terrestrial environments?

    <p>Gravitational effects</p> Signup and view all the answers

    In the context of gas exchange, why do terrestrial animals face challenges compared to aquatic animals?

    <p>Evaporative water loss occurs in air</p> Signup and view all the answers

    What adaptation helps terrestrial animals manage temperature extremes?

    <p>Hibernation strategies</p> Signup and view all the answers

    Which term describes the formation of a resistant stage in tardigrades during harsh conditions?

    <p>Cryptobiosis</p> Signup and view all the answers

    What is a significant challenge for terrestrial animals in relation to reproduction?

    <p>Need for water for gamete transport.</p> Signup and view all the answers

    How does the body structure of aquatic animals help in dealing with the challenges of locomotion in water?

    <p>They possess streamlined shapes to minimize resistance.</p> Signup and view all the answers

    Which adaptation helps marine mammals manage excess salt in their bodies?

    <p>Glands that excrete salt from their respiratory tract.</p> Signup and view all the answers

    What is a key difference in circulation mechanisms between terrestrial and aquatic animals?

    <p>Aquatic animals utilize counter-current exchange in their gills.</p> Signup and view all the answers

    What major obstacle do aquatic organisms face due to the properties of water?

    <p>High viscosity causing difficulty in movement.</p> Signup and view all the answers

    What structural adaptation do terrestrial vertebrates possess to efficiently support their body weight?

    <p>Firmly attached girdles and enclosed ribcages.</p> Signup and view all the answers

    What adaptation allows aquatic endotherms to conserve heat in cold waters?

    <p>Counter-current heat exchange systems.</p> Signup and view all the answers

    In terms of locomotion, what challenge do larger terrestrial animals typically face?

    <p>Insufficient limb thickness to support their weight.</p> Signup and view all the answers

    Which of the following best describes how aquatic environments impact oxygen availability?

    <p>Oxygen levels can be lower than those in the air.</p> Signup and view all the answers

    What adaptation helps terrestrial mammals to maintain their hydration status?

    <p>Absorptive structures in the gut for moisture retention.</p> Signup and view all the answers

    What is one primary reason that endothermic animals find it challenging to stay warm in aquatic environments?

    <p>Water absorbs heat away from the body rapidly.</p> Signup and view all the answers

    What distinctive characteristic do hydrostatic skeletons possess?

    <p>They rely on muscle contraction to change shape.</p> Signup and view all the answers

    Which feature contributes to both aquatic and terrestrial animals in terms of their physical structure?

    <p>Hard skeletons providing support across various habitats.</p> Signup and view all the answers

    What is one of the main purposes of having a mineral bank in animals with endoskeletons?

    <p>To supply minerals for physiological requirements.</p> Signup and view all the answers

    What occurs to enzymes when the temperature exceeds 45°C?

    <p>Proteins denature and lose functionality</p> Signup and view all the answers

    What is a primary challenge that terrestrial environments impose on animals?

    <p>Regulation of body temperature</p> Signup and view all the answers

    What thermoregulation strategy allows body temperature to fluctuate significantly?

    <p>Heterothermy</p> Signup and view all the answers

    Which mechanism describes the transfer of heat through direct contact?

    <p>Conduction</p> Signup and view all the answers

    What is a disadvantage of ectothermy for animals?

    <p>Loss of performance with temperature changes</p> Signup and view all the answers

    What is the purpose of countercurrent heat exchange in cold-climate endotherms?

    <p>To maintain a stable body temperature</p> Signup and view all the answers

    Which term best describes the condition when an organism minimizes metabolic rates to conserve energy?

    <p>Torpor</p> Signup and view all the answers

    What adaptation allows bees to maintain a higher thoracic temperature during flight?

    <p>Muscle activity generating heat</p> Signup and view all the answers

    What evolutionary strategy might be employed by certain ectotherms to survive freezing temperatures?

    <p>Freeze avoidance</p> Signup and view all the answers

    Which term refers to the seasonal form of torpor that occurs during periods of low temperature?

    <p>Hibernation</p> Signup and view all the answers

    How do ectothermic animals thermoregulate in varying environmental conditions?

    <p>By behavioral adaptations to their surroundings</p> Signup and view all the answers

    What strategy allows certain terrestrial ectotherms to withstand ice formation in their bodies?

    <p>Ice nucleation control</p> Signup and view all the answers

    What defines the metabolic rate of endothermic organisms as compared to ectothermic organisms?

    <p>Endotherms maintain constant body temperature despite environmental changes</p> Signup and view all the answers

    What challenge does desiccation present for terrestrial organisms?

    <p>Difficulty in reproduction</p> Signup and view all the answers

    Which factor contributes to the low oxygen content found in water compared to air?

    <p>Variations in water temperature and salinity</p> Signup and view all the answers

    How do marine birds and reptiles primarily manage excess dietary salt?

    <p>By excreting it through specialized glands</p> Signup and view all the answers

    What is an advantage of aquatic environments for animal size and support?

    <p>Enhanced buoyancy supporting larger body sizes</p> Signup and view all the answers

    What role does a hydrostatic skeleton play in an organism?

    <p>Facilitates movement through muscle contraction</p> Signup and view all the answers

    What distinguishes endothermic animals in aquatic environments from ectothermic animals?

    <p>Their ability to regulate body temperature using metabolic heat</p> Signup and view all the answers

    What is a primary challenge of living in dense aquatic environments for smaller animals?

    <p>Higher metabolic costs during locomotion</p> Signup and view all the answers

    How do aquatic endotherms typically regulate their body temperature?

    <p>Using counter-current heat exchange mechanisms</p> Signup and view all the answers

    What is a common trait of isometric growth in organisms?

    <p>Proportional increase in all dimensions</p> Signup and view all the answers

    Which term describes the need for limbs to grow allometrically in larger organisms?

    <p>To efficiently support their increased weight</p> Signup and view all the answers

    What feature is pivotal for fish to maintain efficient gas exchange?

    <p>Counter-current exchange in gill structures</p> Signup and view all the answers

    How does the structure of an exoskeleton benefit arthropods?

    <p>It enables efficient locomotion with mobile limb joints</p> Signup and view all the answers

    What challenge does bulk flow present for terrestrial plants compared to aquatic ones?

    <p>Higher resistance to nutrient transport</p> Signup and view all the answers

    What is the primary challenge terrestrial animals face that aquatic animals do not?

    <p>Desiccation of gametes</p> Signup and view all the answers

    How do ectothermic animals generally thermoregulate compared to endothermic animals?

    <p>Their metabolic rate changes with environmental temperature.</p> Signup and view all the answers

    What mechanism allows ectothermic animals to avoid freezing in low temperatures?

    <p>Supercooling of extracellular fluid</p> Signup and view all the answers

    What defines heterothermy in animals?

    <p>Allowing body temperature to vary significantly.</p> Signup and view all the answers

    Which of the following accurately describes countercurrent heat exchange?

    <p>Warm blood heats cool blood flowing in the opposite direction.</p> Signup and view all the answers

    What is one of the main advantages of endothermy for terrestrial animals?

    <p>Ability to remain active in colder environments.</p> Signup and view all the answers

    What is a disadvantage of ectothermy in relation to temperature changes?

    <p>Positively correlated performance with environmental temperature.</p> Signup and view all the answers

    Which factor influences enzyme effectiveness in varying temperatures?

    <p>Active site shape variations</p> Signup and view all the answers

    What is freeze tolerance, and how do some ectothermic animals utilize it?

    <p>Allowing extracellular fluid to freeze while maintaining cell structure.</p> Signup and view all the answers

    What is a consequence of thermal regulation in ectothermic animals?

    <p>Potential loss of performance due to environmental influences.</p> Signup and view all the answers

    What does the term 'osmotic balance' refer to in terrestrial environments?

    <p>The regulation of solute concentrations within the body.</p> Signup and view all the answers

    Which reproduction strategy is most commonly associated with animals in less stable environments?

    <p>Asexual reproduction for rapid population growth.</p> Signup and view all the answers

    What adaptation in embryonic development is characteristic of amniote vertebrates?

    <p>Formation of an amniotic membrane for protection.</p> Signup and view all the answers

    What is a significant challenge terrestrial animals must overcome compared to their aquatic counterparts?

    <p>Managing desiccation and water loss</p> Signup and view all the answers

    Which adaptation helps terrestrial animals cope with limited water availability?

    <p>Keratinous waterproof outer layer</p> Signup and view all the answers

    How do kangaroo rats manage their water loss in arid environments?

    <p>By increasing metabolic water production</p> Signup and view all the answers

    What is the purpose of the Loop of Henle in mammals?

    <p>To conserve water during urine production</p> Signup and view all the answers

    Which of the following is a method of asexual reproduction in rotifers when conditions are favorable?

    <p>Parthenogenesis producing clones</p> Signup and view all the answers

    How do insects minimize water loss from their respiratory system?

    <p>Through closing spiracles</p> Signup and view all the answers

    What form of gas exchange system is primarily used by insects?

    <p>Tracheal system</p> Signup and view all the answers

    What is a strategy used by desert-dwelling frogs during periods of extreme dryness?

    <p>Aestivation beneath the surface</p> Signup and view all the answers

    Which of the following is not a characteristic of gas exchange in terrestrial animals?

    <p>Direct absorption of oxygen through skin</p> Signup and view all the answers

    What allows mammals to excrete nitrogenous waste while conserving water?

    <p>The structure of the nephron</p> Signup and view all the answers

    What type of life cycle strategy do rotifers employ in moist environments?

    <p>Parthenogenesis for immediate population growth</p> Signup and view all the answers

    What is one physiological limitation imposed by the terrestrial environment compared to aquatic environments?

    <p>Need for gravity compensation in body structures</p> Signup and view all the answers

    What role do daughter cells play in the skin's superficial layers?

    <p>They push older cells towards the surface.</p> Signup and view all the answers

    Which function do cells of exchange surfaces primarily serve?

    <p>Controlling access to the internal environment.</p> Signup and view all the answers

    How do internal cells contribute to maintaining homeostasis?

    <p>They maintain a constant internal environment.</p> Signup and view all the answers

    What is the primary method through which cells deal with wear and tear?

    <p>Rapid turnover of cells.</p> Signup and view all the answers

    What type of secretions cover exchange surfaces to protect them?

    <p>Mucous secretions to trap microbes.</p> Signup and view all the answers

    What type of egg do amphibians typically lay in water?

    <p>Amniotic eggs</p> Signup and view all the answers

    What is required for fertilization in amniotic egg species?

    <p>Internal fertilization</p> Signup and view all the answers

    Which adaptation helps protect embryos from desiccation in terrestrial vertebrates?

    <p>Thick covering on egg or embryo</p> Signup and view all the answers

    What mechanism do most terrestrial animals use to adapt to temperature extremes?

    <p>Metabolic activity</p> Signup and view all the answers

    Which feature of the amniotic egg supports the developing embryo?

    <p>Extraembryonic membranes</p> Signup and view all the answers

    What is a challenge that animals face on land compared to aquatic environments?

    <p>Desiccation of gametes</p> Signup and view all the answers

    What typically characterizes the type of skeleton found in larger terrestrial animals?

    <p>Robust and weight-bearing</p> Signup and view all the answers

    How do terrestrial animals generally cope with the absence of water for fertilization?

    <p>Through internal fertilization</p> Signup and view all the answers

    What is necessary for rapid circulation in animals with high metabolic rates?

    <p>Flexible vessels and a muscular pump</p> Signup and view all the answers

    Which of the following characteristics distinguishes open circulatory systems from closed systems in animals?

    <p>Direct contact of blood with tissues</p> Signup and view all the answers

    What role do the vessels in an animal's circulatory system primarily serve?

    <p>To transport nutrients and remove wastes</p> Signup and view all the answers

    What is a common structural feature of both plant and animal circulatory systems?

    <p>Presence of a network of tubes</p> Signup and view all the answers

    Which condition is essential for the movement of fluids in the circulatory system of animals?

    <p>Forces generated by muscular pumps</p> Signup and view all the answers

    What is the primary purpose of osmoregulation in organisms?

    <p>To regulate the internal osmotic environment of cells</p> Signup and view all the answers

    Which statement accurately describes diffusion?

    <p>It is the tendency of molecules to spread from areas of high abundance to areas of low abundance.</p> Signup and view all the answers

    What does Fick's Law of Diffusion state?

    <p>The diffusion rate is directly proportional to the diffusion coefficient and the difference in concentration.</p> Signup and view all the answers

    How does the concept of bulk flow benefit organisms?

    <p>It enables the efficient distribution of nutrients and waste throughout the body.</p> Signup and view all the answers

    What is meant by concentration gradient?

    <p>A spatial difference in the abundance of a particular molecule.</p> Signup and view all the answers

    What type of pressure is primarily involved in osmosis?

    <p>Osmotic pressure due to solute concentration differences.</p> Signup and view all the answers

    What best describes hydrostatic pressure?

    <p>It results from the weight of fluid in a column above a given point.</p> Signup and view all the answers

    What is the effect of hyperosmotic solutions on cells?

    <p>They can cause cells to lose water and shrink.</p> Signup and view all the answers

    What does the quantity of particles moving across the membrane depend on, all else being equal?

    <p>Surface area of the membrane</p> Signup and view all the answers

    What defines a hypoosmotic solution?

    <p>It has a lower osmolality than the reference solution.</p> Signup and view all the answers

    What is the process called when water moves from a region of low solute concentration to high solute concentration?

    <p>Osmosis</p> Signup and view all the answers

    Which term refers to the osmotic concentration of a solution in osmoles?

    <p>Osmolality</p> Signup and view all the answers

    In osmosis, when water moves across a semi-permeable membrane, which direction does it flow considering osmotic potential?

    <p>From areas of high osmotic potential to low osmotic potential</p> Signup and view all the answers

    What does higher osmotic potential indicate?

    <p>Lower solute concentration</p> Signup and view all the answers

    What happens to a red blood cell placed in a hyperosmotic solution?

    <p>It shrinks</p> Signup and view all the answers

    What kind of pressure affects how water crosses a membrane from a high to a low osmotic potential?

    <p>Pressure potential</p> Signup and view all the answers

    Which of the following terms describes the sum of osmotic potential and pressure potential?

    <p>Water potential</p> Signup and view all the answers

    What is one of the key functions of the nephron?

    <p>Producing concentrated urine</p> Signup and view all the answers

    How do aquatic animals primarily excrete ammonia?

    <p>Through diffusion into the environment</p> Signup and view all the answers

    What method do terrestrial animals primarily use to eliminate ammonia?

    <p>Conversion to uric acid or urea</p> Signup and view all the answers

    What primary structure utilizes ciliated cells for filtration?

    <p>Protonephridium</p> Signup and view all the answers

    What substance do Malpighian tubules primarily secrete into their lumen?

    <p>Uric acid</p> Signup and view all the answers

    How is the process of urine formation mainly categorized in the excretory tubule?

    <p>Filtration, secretion, reabsorption</p> Signup and view all the answers

    Which of the following is NOT a feature of metanephridia?

    <p>Uses flame cells for filtration</p> Signup and view all the answers

    What is the role of the Loop of Henle in the nephron?

    <p>Concentrate urine</p> Signup and view all the answers

    What type of waste do reptiles and birds primarily excrete to conserve water?

    <p>Uric acid</p> Signup and view all the answers

    Which term describes the active transport mechanism involved in reabsorbing ions between the extracellular fluid and filtrate?

    <p>Co-transport</p> Signup and view all the answers

    What is homeostasis primarily responsible for maintaining in an organism?

    <p>A stable internal environment</p> Signup and view all the answers

    What is the significance of negative feedback in homeostasis?

    <p>It regulates physiological variables back to a setpoint.</p> Signup and view all the answers

    Which of the following variables must organisms regulate to achieve homeostasis?

    <p>Nutrients and gases</p> Signup and view all the answers

    How do changes in temperature primarily affect biochemical reactions within organisms?

    <p>They influence enzyme activity.</p> Signup and view all the answers

    What is a primary characteristic of allometric growth in animals?

    <p>Growth rates of various body parts vary</p> Signup and view all the answers

    What role does gas exchange play in maintaining homeostasis?

    <p>It balances the exchange of O2 and CO2.</p> Signup and view all the answers

    What evolutionary significance is associated with allometric growth?

    <p>It correlates with trends in body size changes in a lineage</p> Signup and view all the answers

    What is a critical aspect of osmoregulation in aquatic environments?

    <p>Regulating internal water and solute balance</p> Signup and view all the answers

    What effect does a stable internal environment have on metabolic processes?

    <p>It enhances reaction efficiencies.</p> Signup and view all the answers

    How does water help aquatic animals in terms of body mass?

    <p>It reduces the necessity for limb adaptation</p> Signup and view all the answers

    How does cell location influence an organism's approach to homeostasis?

    <p>It impacts environmental exposure and nutrient accessibility.</p> Signup and view all the answers

    In the given example, what trait of Varanus species illustrates positive allometry?

    <p>Increase in humerus thickness</p> Signup and view all the answers

    What is an implication of allometry on the limbs of terrestrial animals as they grow larger?

    <p>Limbs must grow disproportionately thicker to support body weight</p> Signup and view all the answers

    What is the primary function of the middle ear in terrestrial animals?

    <p>Amplifying vibrations for improved sound detection</p> Signup and view all the answers

    What type of transport is primarily involved in moving ions between extracellular fluid and filtrate in excretory tubules?

    <p>Active transport</p> Signup and view all the answers

    How do terrestrial vertebrates sense chemical signals effectively?

    <p>With moist olfactory epithelium and taste buds</p> Signup and view all the answers

    Which excretion process is more suitable for terrestrial animals to eliminate ammonia due to its toxicity?

    <p>Excretion in urine as urea</p> Signup and view all the answers

    Why is it important for terrestrial animals to sense the direction that is down?

    <p>To orient themselves in their environment</p> Signup and view all the answers

    What challenge do terrestrial animals face due to the scaling of body mass and limb area?

    <p>Insufficient support for body weight as size increases</p> Signup and view all the answers

    What is the primary function of the loop of Henle in nephron structure?

    <p>Concentration of urine</p> Signup and view all the answers

    Which structure is responsible for filtering extracellular fluid in certain organisms?

    <p>Protonephridium</p> Signup and view all the answers

    How do insect antennae function as chemosensors?

    <p>They contain wet channels lined with adsorptive tissue</p> Signup and view all the answers

    In which type of circulatory system is the metanephridium associated?

    <p>Closed circulatory system</p> Signup and view all the answers

    What adaptation allows for the effective transmission of sound from air to the inner ear of terrestrial animals?

    <p>The transformation of vibrations by middle-ear bones</p> Signup and view all the answers

    What characteristic of water affects how sound is transmitted compared to air?

    <p>The speed of sound is significantly higher in water</p> Signup and view all the answers

    What is the main reason land animals produce uric acid instead of ammonia?

    <p>It is less toxic and conserves water</p> Signup and view all the answers

    Ammonia excretion via diffusion is primarily found in which type of organism?

    <p>Aquatic organisms</p> Signup and view all the answers

    What is a key characteristic of the hearing mechanism in fish?

    <p>It utilizes vibrations transmitted through tissues</p> Signup and view all the answers

    What type of excretory structure does an insect utilize for removing nitrogenous waste?

    <p>Malpighian tubules</p> Signup and view all the answers

    What role does the robust skeleton play in terrestrial animals?

    <p>It supports body weight against gravity</p> Signup and view all the answers

    What is the desired outcome of filtration, reabsorption, and secretion processes in excretory systems?

    <p>Production of concentrated urine</p> Signup and view all the answers

    In terms of sound transmission, what factor must terrestrial animals account for?

    <p>Sound travels better in air than in water</p> Signup and view all the answers

    What is the role of co-transporters in the excretory tubule?

    <p>Transporting nutrients and ions against concentration gradients</p> Signup and view all the answers

    What is the primary characteristic of open circulatory systems in insects?

    <p>Hemolymph comes into direct contact with tissues.</p> Signup and view all the answers

    What distinguishes closed circulatory systems from open circulatory systems?

    <p>Blood is contained in vessels and never contacts tissues.</p> Signup and view all the answers

    What role do valves in the heart play in the circulatory system?

    <p>They maintain unidirectional flow of blood.</p> Signup and view all the answers

    Which of the following is a function of the muscular pump in the heart?

    <p>To create pressure and directional flow.</p> Signup and view all the answers

    How does blood pressure change as it moves from arteries to capillaries?

    <p>Blood pressure drops significantly.</p> Signup and view all the answers

    What is the purpose of capillary beds in the circulatory system?

    <p>To exchange substances between blood and tissues.</p> Signup and view all the answers

    What is the primary advantage of asexual reproduction over sexual reproduction?

    <p>It allows for rapid population growth.</p> Signup and view all the answers

    What adaptation allows mammals to efficiently deliver oxygen to their tissues?

    <p>Complete separation between the ventricles.</p> Signup and view all the answers

    In a closed circulatory system, what happens to blood velocity as it passes through capillaries?

    <p>Blood velocity decreases rapidly.</p> Signup and view all the answers

    Which type of reproduction involves the fusion of haploid gametes to form a diploid zygote?

    <p>Sexual reproduction</p> Signup and view all the answers

    What is the common reproductive strategy of males in sexual reproduction?

    <p>To produce abundant small motile gametes.</p> Signup and view all the answers

    What is the primary transport fluid in open circulatory systems?

    <p>Hemolymph.</p> Signup and view all the answers

    What is a significant disadvantage of sexual reproduction?

    <p>It requires complex fertilization processes.</p> Signup and view all the answers

    What physiological feature helps regulate blood distribution in arteries?

    <p>Vessel diameter.</p> Signup and view all the answers

    What type of development occurs when cells that give rise to gametes are isolated early in development?

    <p>Gametogenesis</p> Signup and view all the answers

    Why do larger vessels have lower resistance compared to smaller vessels?

    <p>They have a larger cross-sectional area.</p> Signup and view all the answers

    What defines a dioecious organism?

    <p>It has two separate sexes.</p> Signup and view all the answers

    In mammals, how does oxygen-poor blood return to the heart?

    <p>Through veins.</p> Signup and view all the answers

    What impact does gravity have on blood flow in vertebrates?

    <p>It requires higher pressure for circulation.</p> Signup and view all the answers

    In which reproductive strategy does each fragment of an organism give rise to a new individual?

    <p>Fragmentation</p> Signup and view all the answers

    How are sperm cells adapted for their function?

    <p>They are highly modified and simplified.</p> Signup and view all the answers

    What is a primary reason for the bulk flow of fluids being maintained in a closed circulatory system?

    <p>Presence of valves prevents backflow.</p> Signup and view all the answers

    What major process follows fertilization in animal development?

    <p>Gastrulation</p> Signup and view all the answers

    What is the primary purpose of the acrosome in sperm cells?

    <p>To penetrate the egg's outer membrane.</p> Signup and view all the answers

    Which of the following describes parthenogenesis?

    <p>Development from an unfertilized egg.</p> Signup and view all the answers

    What characteristic distinguishes hermaphroditic organisms?

    <p>They possess both male and female reproductive systems.</p> Signup and view all the answers

    Which of the following processes generates genetic variation in offspring?

    <p>Meiosis</p> Signup and view all the answers

    Study Notes

    Terrestrial Animals

    • Animals originated in the oceans
    • Land-dwelling animal lineages are descended from ancestors that independently left the aquatic environment to live on land
    • The earliest recorded terrestrial animal was a myriapod, 428 million years old, but the first transition must have occurred earlier.

    Relatively Few Terrestrial Animal Taxa

    • Gastropods, arthropods (insects, arachnids, myriapods, crustaceans), nematodes, annelids, and amniote vertebrates, etc.
    • These taxa encompass numerous species, and terrestrial environments have provided many evolutionary opportunities.

    Conditions on Land

    • Gravity affects terrestrial animal posture and locomotion.
    • Air is less dense than water, requiring adaptations for oxygen intake.
    • Locomotion and sensory modes differ significantly from aquatic environments.
    • Maintaining sufficient water resources is critical.
    • Sunlight exposure to UV radiation also poses challenges, requiring adaptations for protection.

    Life on Land

    • Terrestrial animals avoid desiccation through mechanisms to reduce water loss and replace lost water.
    • Desiccation tolerance (aestivation, life cycles) is another important adaptation.
    • Excretion with limited water loss is necessary.
    • Gas exchange organs, such as lungs, book lungs, and tracheal systems, are internalized to minimize desiccation.

    Dessication and the Environment - Terrestrial Animals

    • Terrestrial animals are constrained by water availability.
    • This constraint significantly affects their anatomy, behavior, and physiology.

    Nitrogenous Wastes

    • Toxic ammonia (NH3) is produced in every cell by catabolism of amino acids and nucleic acids.
    • Reptiles, birds, and insects convert ammonia to uric acid, a semi-solid substance with low water solubility, allowing for water conservation during excretion.

    Desiccation and The Environment - Mammals

    • Mammals are ureotelic, converting ammonia into less toxic urea.
    • The loop of Henle plays a crucial role in water conservation in mammals.
    • Concentrated urine is produced, which is hyperosmotic to blood; the longer the loop, the better water conservation.

    Desiccation and The Environment - Kangaroo Rats

    • Kangaroo rats, desert-adapted rodents, have a very long loop of Henle, enabling the production of highly hyperosmotic urine (22.5% of daily water loss).
    • Efficient water conservation is essential for survival in arid environments.
    • Metabolic water is important.

    Desiccation and The Environment - Insects

    • Insects must deal with their small size (surface area to volume ratio).
    • Water loss through evaporation of body surfaces and respiratory surfaces is a challenge.
    • Waxy outer layers are found to minimize evaporative water loss.
    • The closing of spiracles in the tracheal system further reduces evaporative water loss in terrestrial environments.

    Desiccation Tolerance

    • Terrestrial tardigrades form a resistant stage (tun) in response to dehydration and sub-zero temperatures.
    • Upon rehydration, they return to their active state.

    Rotifer Life Cycle

    • In unstressed environments (moist), rotifers reproduce asexually (parthenogenesis).
    • In stressed environments (dry), they reproduce sexually, forming a diploid (desiccation-resistant) zygote.

    Aestivation

    • Aestivation is a prolonged period of depressed metabolism to avoid seasonal heat and drought.
    • Some desert-dwelling spadefoot toads spend most of their lives buried deeply. Their metabolism is depressed; they only emerge when it rains to breed.
    • Some desert-dwelling frogs secrete a cocoon during aestivation.

    More Requirements for Terrestrial Life

    • Desiccation avoidance and tolerance.
    • Excretion with minimal water loss.
    • Internalized bulk flow for fluids and gases.
    • Gravity is a crucial factor.
    • Efficient gas exchange structures are required (lungs, book lungs, tracheae).

    Gas Exchange With Air

    • Breathing air presents challenges, unlike water, diffusion of CO2 is not as readily exchanged.
    • Air has a higher O2 content (21%) compared with water(1-2%).
    • Bulk flow of air, ventilation, requires less muscular effort than water ventilation.
    • Air has low viscosity and low density.

    Gas Exchange With Air – Tracheae

    • A tracheal system delivers air directly to tissues via interstitial fluid.
    • Moist exchange surfaces are internal.

    Desiccation and The Environment - Tracheae

    • Waterproofing of the outer layer of the body is needed to reduce water loss
    • Keratin and wax are essential for keeping the body dry.
    • Minimize exposure of respiratory surfaces to minimize water loss
    • Internal placement of gas-exchange (respiratory) and digestive surfaces

    Nitrogenous Wastes and Excretion

    • Ammonia is toxic and aquatic animals can get rid of it through excretion.
    • Terrestrial animals convert ammonia to less-toxic substances such as urea or uric acid.
    • These substances are excreted while conserving water.

    Desiccation and The Environment - Vertebrate Lungs

    • Vertebrate lungs have a bulk flow of air to the respiratory membrane.
    • Moist exchange surfaces are internal.

    More Requirements for Terrestrial Life

    • Protecting gametes from desiccation.
    • Protecting embryos from desiccation.
    • Adaptations to extreme temperatures (avoidance or tolerance).
    • Constraints on sensory systems, such as chemosensors and mechanosensors (e.g., tympanal organ, middle ear).
    • Supporting body weight through robust skeletons and limb adaptations.

    Reasons for Thermoregulation

    • Terrestrial animals regulate body temperature through metabolic activity and behaviour.
    • The optimal animal body temperature range is about 4 °C to 40 °C.
    • Maintaining a constant body temperature in a variable environment is energetically expensive.
    • Enzyme effectiveness and protein denaturation are affected by fluctuating temperature and pH.

    Reasons for Thermoregulation - Performance

    • Animal performance depends on biochemical processes.
    • Animals regulate body temperatures within ranges allowing optimal performance (maximum running speed of lizards at various body temperatures, range of optimal physiological performance).

    Ways of Thermoregulation

    • Endothermy is producing enough heat through metabolic activity to significantly warm the tissues.
    • Ectothermy is insufficient heat generated through metabolic activities to significantly warm the tissues.
    • Heat is exchanged with the environment.

    Heat Exchange With The Environment

    • Conduction is the transfer of heat by direct contact.
    • Convection is the transfer of heat by the movement of a medium (air or water).
    • Radiation is the transfer of heat as long-wave light.
    • Evaporation is the transfer of heat via energy consumed through change of state from liquid to gas.

    Countercurrent Heat Exchange

    • Cold-climate terrestrial endotherms conserve heat by utilizing countercurrent heat exchange.
    • Warm blood in efferent vessels warms cool blood in afferent vessels within the body.
    • This maintains a temperature gradient, and keeps the core body temperature warmer.

    Torpor and Hibernation

    • Torpor in small endotherms reduces energy demands in periods of low or high temperatures or when resources are unavailable.
    • Metabolic rates are often depressed, and body temperatures drop to conserve energy.
    • Hibernation is a seasonal form of torpor, occurring during periods of low temperature.

    Endothermy in Insects

    • Bees and some flying insects are heterothermic (endothermic) and generate enough heat with activity produced by their flight muscles to maintain a high and constant temperature in the thorax.
    • These insects tend to be furry.

    Freeze Tolerance And Freeze Avoidance

    • Freeze avoidance is when ectotherms can supercool their extracellular fluid down below 0 °C without freezing - mainly marine animals
    • Freeze tolerance is when ectothermic animals can allow the bulk of their extracellular fluid to freeze for extended periods; the high intracellular osmolality reduces the freezing point, and the control of ice nucleation in the extracellular fluid allows this.

    Requirements for Terrestrial Life (cont'd)

    • Protecting gametes from desiccation
    • Protecting embryos from desiccation
    • Adaptations to temperature extremes
    • Sensory systems (chemosensors, mechanosensors)
    • Structural support for body weight (robust skeleton, SA/V relationships, etc.)

    The Senses in Air and Water

    • Air transmits light more effectively than water.
    • Water transmits chemical signals more effectively than air.
    • The speed of sound is far greater in water than in air.

    Chemosensors

    • Chemosensory organs require a wet surface for the adsorption of airborne chemical particles.
    • Insect antennae have minute channels lined with moist and absorbent tissues for picking up scent particles.

    Chemosensors (taste)

    • Terrestrial vertebrates have moist olfactory epithelium and taste buds in the oral cavity.
    • Taste receptors occur in microscopic taste buds that line the sides of the furry papillae.

    Hearing

    • Sound does not transmit easily from air to water.
    • Terrestrial animals have tympanal organs on both sides to pick up the vibrations and use nerves as mechanoreceptors.

    Hearing and Balance

    • Vertebrates have inner ear organs for hearing and sensing acceleration and direction (vestibular labyrinth).

    Hearing in Fish

    • Fish's inner ears can pick up vibrations through tissues.
    • The hyomandibular bone supports the lower jaw in fish.

    Hearing in Tetrapods

    • In tetrapods, middle ear bone(s) transform large-amplitude eardrum vibrations from air to low-amplitude high-force vibrations transmitted to the oval window.
    • This amplifies vibrations, resulting in waves in the fluid-filled cochlea.

    Support Body Weight - Allometry

    • Terrestrial animals are subject to gravity.
    • Organism volume (mass) is proportional to the linear dimension (cubed).
    • Cross-sectional area of the limb (support and strength) is proportional to the linear dimension (squared).
    • Limbs must proportionally increase in size to support growing body mass.
    • Aquatic animals lack this constraint as water supports the body mass (neutral buoyancy).
    • Allometric growth in limbs is observed as terrestrial animals grow larger.

    Allometry

    • Allometric growth is the characteristic of most animals with different parts growing at different rates with increase in overall size and evolutionary phenomenon.

    Allometric Relationships

    • Various allometric relationships demonstrate how body components scale with overall increase in size.

    Support Body Weight (allometry) - Varanus

    • The thickness of the humerus in different Varanus species displays positive allometry, increasing proportionally more than the increase in humerus length.

    Support Body Weight - Allometry - Ant

    • The ant has isometric growth, where the proportionate increase in limb size is similar to the body size.
    • In the real world, the limbs of larger specimens would not have sufficient thickness to allow for efficient locomotion

    Support Body Weight - Sprawling Limb vs erect limb configuration

    • Sprawling limb configuration requires less energy to maintain in ectotherms compared with erect limb configuration in endotherms.

    Hard Skeletons

    • Skeletons perform various functions in aquatic and terrestrial animals.
    • Exoskeletons are external; endoskeletons are internal.
    • Provide attachments and leverage for muscles.
    • Transmit compressive stress to substrates.
    • Act as a mineral bank for physiological requirements (vertebrates).
    • Protect delicate organs.

    Endoskeletons

    • Vertebrate endoskeletons are composed of bone and cartilage.
    • Bone - collagenous matrix mineralized through CaPO4 crystals, is dynamic and alive.
    • Bones provide structural support.
    • Highly vascularised, matrix architecture, and scattered osteocytes contribute to metabolic activity, responding to compressive stress well and to shear stress less well.

    Exoskeletons - Arthropods

    • Arthropod exoskeletons consist of chitin, a complex polysaccharide.
    • May be impregnated with calcium carbonate.
    • Composed of plates (tergae) with joints between them.
    • Tergae mark segmentation of limbs and body, permitting significant mobility in limb joints.
    • Muscles are located within the skeleton.

    Hydrostatic Skeletons

    • Hydrostatic skeletons are fluid-filled cavities surrounded by muscles.
    • Muscular contractions create pressure and shape changes within the body, allowing for movement.
    • Fluid incompressibility is maintained and pressurized when muscles contract.
    • Found in organisms with soft bodies, such as worms.

    Aquatic Animals - Advantages

    • Water supports the body, affecting the size, stance, and skeleton design.
    • Gravity has little effect on the design of the skeleton.
    • Water buoyancy allows animals to attain larger sizes than comparable terrestrial animals.
    • Desiccation is a lesser threat for aquatic animals.
    • Stable and mild temperatures are the norm for aquatic environments
    • Metabolic wastes are removed by diffusion into the surrounding water.
    • Sound transmits effectively from water to body tissue.

    Aquatic Environments - Challenges

    • Water is dense, making movement energy-intensive.
    • Water is viscous, hindering movement.
    • A water layer clings to the body surface.
    • Water often has low oxygen content compared to air.
    • Water temperatures vary significantly among different sources and locations.
    • Water has very high thermal conductance
    • Water is a good conductor of heat making it difficult to maintain a constant body temperature.

    Osmoregulation in ANIMALS

    • Organisms regulate the internal osmotic environment
    • Osmoregulation is the process by which organisms maintain a suitable internal environment by controlling the solute concentration and water balance across cell membranes.

    Osmoregulation in ANIMALS (terrestrial)

    • Terrestrial environments are dry.
    • Organisms lose water from the body surface through evaporation and in waste products.
    • Osmoregulation is a process of water intake and conservation, and a critical balance between water gain and loss.
    • Salt (ion) loss is a major concern in terrestrial animals.

    Osmoregulation (aquatic) - Marine

    • Marine organisms are hypoosmotic to their environment, losing water and gaining salt.
    • They must regulate the internal environment via drinking seawater to gain water and replace the lost water.
    • Eliminate excess salt from the body through their specialized osmoregulatory systems, typically through specialized excretory organs or tissues, in order to maintain stable salt loss and gain in the body.

    Osmoregulation (aquatic) - Freshwater

    • Freshwater organisms are hyperosmotic to their environment, gaining water but losing salt.
    • They regulate by drinking little water to conserve salt and by excreting dilute urine.

    Osmoregulation (aquatic) – Elasmobranchs

    • Elasmobranchs are iso-osmotic to seawater.
    • However, their internal concentrations of Na+, K+, and Cl⁻ are lower than the surrounding seawater.
    • Specialized structures like rectal glands compensate for the difference by creating a highly concentrated salt solution, to be excreted.

    Tonicity and the Environment - Water Dwellers

    • Body fluid osmolality varies among aquatic organisms.
    • Some marine groups are iso-osmotic with seawater and maintain constant osmolality.

    Tonicity and the Environment - Land Dwellers

    • Desiccation and water loss is constant in a terrestrial environment.
    • Water proofing is critical.
    • Minimizing electrolyte intake is very important.

    Summary of Responses to the Osmotic Environment

    • Terrestrial environments require adjustments for water loss and salt intake/output.
    • Marine and freshwater environments present significant challenges regarding water/salt balance.

    Active Regulation of Water Loss and Gain, Excretion, and Waste

    • Active regulation is critical for maintaining the correct water, solute, and pH balance in the extracellular fluids of aquatic organisms.
    • Organisms using diffusion into water use the surrounding water to eliminate wastes.
    • Excretory tubules are associated with kidneys and eliminate waste materials as a liquid.
    • Filtration (nonselective) involves small molecules and ions being filtered from blood to fluid.
    • Reabsorption is selective (ions needed are reabsorbed), and secretion is selective (excess ions are discharged to waste).

    Ammonia Excretion

    • Ammonia is a toxic nitrogenous waste product in aquatic environments and animals need to remove it.
    • Aquatic animals often eliminate ammonia through diffusion.
    • Terrestrial animals often convert ammonia to urea or uric acid for easier excretion.

    Protonephridia

    • Protonephridia filter extracellular fluids and remove wastes in many of the simpler aquatic animals.
    • Waste material is removed by ciliated flame cells into a series of ducts where reabsorption occurs.

    Metanephridia

    • Metanephridia filter coelomic fluids into the circulatory system through blood vessels.
    • Associated with a closed circulatory system.

    Malpighian Tubules

    • The Malpighian tubules in insects secrete uric acid and ions into the lumen (fluid-filled tube) of the tubule.
    • Water follows through osmosis, and filtrate is released into the gut to maintain water, ion, and waste homeostasis.

    Nephron

    • Nephrons filter water and solutes from the blood and reabsorb water and solutes into the blood to produce concentrated urine.
    • The loop of the Henle plays a crucial role in regulating urine concentration.

    Homeostasis and Circulation

    • Circulation is needed to maintain stable pH, osmolarity, waste removal, deliver nutrients, conduct gas exchange with the environment.
    • The circulatory system can include a pump for pressure, fluid conducting vessels and/or diffusion, depending on the relative size and complexity of the organisms.

    Types of Circulation in Animals

    • Open circulatory systems occur when blood or hemolymph is not contained in vessels and is pumped into a hemocoel (body cavity); no distinction between hemolymph and interstitial fluids.
    • Blood under pressure, often in closed systems, is well adapted for large animals and high metabolic rate organisms. Circulatory systems can include a pump (cardio) and vessels for high and continuous flow in a closed system, or only vessels and bulk transport in simpler open systems.

    Circulation in Animals - Closed System

    • Blood is contained within blood vessels; blood under pressure, with specialized vessels for constant flow.
    • Vessels and hearts that form continuous circuits are necessary for prolonged, high-activity rates.
    • The circulatory system interacts with gas exchange surfaces and tissues efficiently
    • All vertebrate animals use circulatory systems for movement and regulation.

    Circulation in Animals - The Heart

    • The heart functions as a muscular pump that creates pressure to drive blood flow.
    • Closed circulatory systems allow one-way blood flow.
    • The heart and blood vessel structure changes in closed systems help maintain and regulate blood pressure to transport blood efficiently.
    • Open systems may have a pump and vessels, but blood is not always in close contact with body tissues

    The Heart and Blood Vessels

    • In closed circulatory systems, the heart maintains bulk fluid flow in the face of resistance.
    • Blood flow depends on pressure and resistance.
    • Resistance varies with blood vessel length, diameter, and the degree of smoothness of the vessel walls.
    • Variations directly affect the flow rate.

    The Heart and Blood Vessels - Blood Pressure and Velocity

    • Blood pressure (drops considerably) and velocity vary with distance from the heart (due to distance from the heart) and the total volume occupied, and the resistance from vessels being smaller in diameter.

    Blood Vessels and Blood - Function

    • Arteries carry blood away from the heart under high pressure.
    • Veins carry blood back to the heart, where expansion allows low pressure, flow or transport.
    • Capillaries facilitate gas and solute exchange between blood and tissues.
    • Blood, the extracellular fluid (ECF) of vertebrates, has plasma (water, ions, proteins, nutrients, and gas), erythrocytes (RBCs with respiratory pigments like hemoglobin), and leukocytes (WBCs).
    • Platelets are needed for blood clotting.

    Blood Vessels and Blood - Composition

    • Blood (vertebrate ECF) is composed of plasma (water, ions, proteins, nutrients, gas) and cells (erythrocytes, leukocytes, platelets).
    • Different components play different functions.

    Vertebrate Circulatory Systems

    • Variation in circulatory systems in vertebrates is related to whether or not gravity is a major factor, gas exchange locations (gills, lungs, or skin), and thermoregulatory modes (ectothermy or endothermy).
    • The circulatory systems of fish are characterized by the low-pressure, single loop system where blood vessels carry blood directly to the gills and then to the body; while endotherms often have a higher pressure, specialized four-chambered heart for efficient oxygen delivery (and blood regulation) to all body tissues.

    Homeostasis and Gas Exchange

    • Gas exchange is crucial for efficient metabolism; the process of acquiring oxygen and releasing carbon dioxide is critical for maintaining homeostasis.

    Partial Pressure Gradients in the Body

    • Diffusion in gas exchange relies on differences in partial pressures of oxygen and carbon dioxide.
    • Circulatory systems maintain these gradients.

    Gas Exchange with the ECF

    • Surface area for gas exchange is proportional to body mass and metabolic rate. Gas exchange surfaces have characteristics required for effective diffusion.
    • Gas exchange can occur in a single large structure or multiple small structures.
    • Air and water are used as respiratory media for gas exchange, such as gills, tracheae and lungs.

    Gas Exchange With the ECF, Capillary/Cell Interface

    • Gas exchange between blood and tissue fluids occurs at the capillaries.
    • The small diameter, extensive surface area, and thin walls in the capillary bed maximize efficiency of gas exchange.

    Gas Exchange with the ECF - The Vertebrates

    • Large animals often have highly vascularized and complicated systems with cross-current flow to support gas exchange between the environment in the air or water and the body, and with the fluid pools within the circulatory systems.

    Gas Exchange with the ECF - Birds

    • Birds have cross-current gas exchange in their lungs, which maximizes gas exchange efficiency.
    • Air flows in only one direction through the rigid (air sac) lungs, leading to highly effective gas exchange.
    • Two cycles of ventilation ensure that the lungs are completely cleared for effective gas exchange.

    Homeostasis and Acid-Base (pH) Regulation

    • Maintaining proper levels of pH is essential for cellular function.
    • pH often regulates the rate and efficiency of protein function, and the balance among other biochemical regulation processes.
    • Controlling levels of gases like CO2 and the concentration of bicarbonate is important for controlling blood pH.
    • Sensors monitor the extracellular fluid pH, and feedback signals trigger changes to other body systems to effect the needed adjustments.

    Acid-Base Regulation - Chemical Buffers

    • Renal and physiological chemical buffering and gaseous excretion systems can regulate pH and maintain correct concentrations of ions.
    • Proton/bicarbonate pump activity for acid-base control, by shifting reactions left or right.

    Recap of Theme 1 (animals):

    • Homeostasis is essential for the functioning of organisms and the maintenance of a stable internal environment of pH and osmolarity.
    • Osmoregulation, circulation, gas exchange, and pH regulation are all necessary processes that allow for proper homeostasis.

    Recap of Theme 1 (animals): Circulation

    • Circulatory systems move fluid (ECF) around the body.
    • Plants and animals have different circulatory system needs and types.
    • Animals require hearts, blood vessels, and blood for transport.
    • Both closed and open circulatory systems circulate fluids, relying on hydrostatic pressure, but differences exist in how efficient that circulation is.

    Recap of Theme 1 (animals): Gas Exchange

    • Gas exchange between cells and atmosphere is needed for all life forms.
    • Characteristics of a good gas exchange structure reflect diffusion and bulk flow.

    Recap of Theme 1 (animals): pH Regulation

    • pH homeostasis controls [H+] in the body
    • Gases, like CO2, influence extracellular fluid pH through carbonic acid buffering systems.
    • Other physiological processes and organs regulate the body's pH.

    Theme 5 Recap (animals) - Sexual vs. Asexual Reproduction

    • Sexual reproduction requires gametes (sperm and egg) from two parents (diploid), produced via meiosis. The genetic diversity allows for adaptation to changing environments. Asexual reproduction does not require mating; instead, offspring arise from a single parent via mitosis. Asexual strategies may increase efficiency of producing offspring in stable environments

    Theme 5 Recap (animals) - Fertilization

    • External fertilization occurs in aquatic environments, often with high egg mortality and large numbers of released gametes.
    • Internal fertilization is widespread in terrestrial and some aquatic animals. The strategy features reduced egg production and relatively small amounts/numbers of eggs.

    Theme 5 Recap (animals) - Embryo Protection

    • Aquatic embryos are protected by jelly layers or similar structures.
    • Terrestrial embryos have extraembryonic membranes for support and protection in a terrestrial environment (amniotic eggs)
    • Viviparity and ovoviviparity are other strategies for protecting embryos

    Theme 5 Recap (animals) - Early Development

    • Important processes in early development include cleavage (cell divisions), blastula (hollow ball of cells), and gastrulation (formation of three germ layers).
    • Morphogenesis and organogenesis are essential parts of embryonic development, where organismal forms are created.

    Theme 5 Recap (animals) - Gametes

    • Germ cells (gametes) are specialized cells produced via meiosis.
    • The life cycle is largely diploid (2n) except for the germ cells.
    • Gametogenesis is the formation of gametes using mitosis for increasing numbers and meiosis for genetic diversification

    Theme 5 Recap (animals) - Reproductive Systems

    • Male reproductive systems typically produce sperm in the testes and transport those via sperm ducts to external opening or copulation.
    • Female systems typically produce eggs in ovaries and transport to an external or internal site or tract for fertilization.

    Hermaphroditism

    • Some animals possess functional reproductive systems of both sexes, which may be either simultaneous or sequential

    Fertilization and Early Development

    • Fertilization unites egg and sperm (resulting in a zygote), with one sperm necessary.
    • Early development includes cell division, blastula and gastrula stages, and then pattern and organogenesis of the new organism.

    External Fertilization

    • In aquatic environments, gamete release is often coordinated with other individuals
    • Frequently involves large numbers of eggs
    • The high probability of egg mortality implies the need for significant quantities of gametes
    • Often triggered by changes in environmental cues, such as seasonal changes

    Internal Fertilization

    • Copulation often accompanied by specialized organs.
    • Sperm are often packaged and delivered into the female reproductive tract
    • Fewer eggs are required, increasing egg survival rates

    Ovoviviparity

    • Fertilized eggs are retained within the mother's body
    • The mother provides varying levels of care (gas exchange and nutrient transfer) to the embryos

    Early Development (ontogeny) - Cellular Processes

    • Cellular processes like mitosis, cell migration, programmed cell death, cell interactions, and induction are critical to morphogenesis.
    • These processes lead to determination of cell fates and the differentiation of specialized cells

    Early Development (ontogeny) - Gastrulation

    • Gastrulation involves the formation of ectoderm, endoderm, and mesoderm, which allow for the establishment of body axes and the process of morphogenesis.

    Early Development (ontogeny) - Frog Gastrulation

    • The amount of yolk in an egg affects the form of the blastula and influences the gastrulation process.
    • In species with relatively little yolk, gastrulation is often more uniform and easier to follow

    Early Development (ontogeny) - Embryonic Tissue Layers

    • Ectoderm, endoderm, and mesoderm give rise to different systems in the developing organism

    Organogenesis

    • Organogenesis is the process of cell differentiation and division from the three germ layers.
    • Organ rudiments are formed.
    • The cell interactions and determination of cells influence the type of cell that develops

    Organogenesis - Neuration

    • Neurulation is a complex cell differentiation, growth, and apoptosis process that produces the dorsal hollow nerve tube in chordates.
    • Cells involved in neurulation take on specific cytoskeletal organizational changes in response to chemical signals from the notochord that reorient and cause folding of the neural plate

    Ovum Structure

    • Egg, or ovum, has cytoplasmic determinants (yolk) stored unevenly, which influence the rate of cleavage and cell size distributions during development.

    Early Development (ontogeny) - Cytoplasmic Determinants

    • Cytoplasmic determinants are mRNA and proteins from the mother's genome that determine developmental processes and fates.

    Drosophila - Developmental Model Organism

    • Drosophila is an excellent model organism for studying development.
    • It exhibits a highly conserved developmental process from the egg to the adult, with significant development occurring via synchronous mitotic divisions without the intervention of cytokinesis to form a syncytium

    Drosophila - Developmental Model Organism - Segmentation and Morphology

    • Dorsophila exhibit one-to-one correspondence between the larval and adult segments. This facilitates identification of developmental regions and the observation of developmental changes.

    Pattern Formation - Establishment of Major Body Axes

    • Pattern formation establishes the anterior, posterior, dorsal, and ventral body axes.

    Pattern Formation in Drosophila - Bicoid

    • Bicoid is a maternal-effect gene.
    • Bicoid protein is produced and distributed unevenly at the anterior pole and influences the establishment of the anterior-posterior axis
    • Cytokinesis at blastulation isolates differing bicoid protein concentrations in individual cells.

    Pattern Formation in Drosophila - Molecular Control

    • Maternal-effect genes control the polarity of the egg and thus, the embryo.
    • Gap genes segment the embryo.
    • Pair-rule genes establish smaller units of the segment pattern, and
    • Segment polarity genes establish the anterior-posterior pattern within the segment.

    Homeotic Genes (Hox Genes) in Drosophila

    • Hox genes in Drosophila are arranged in a linear fashion along the chromosome, reflecting their expression along the body.
    • Hox genes are strongly conserved across animal taxa, suggesting their fundamental importance in pattern formation.
    • Hox genes produce transcription factors that control the expression of genes for segment-specific structures and regulate developmental processes and organismal structure.

    Early Development (ontogeny) - Cellular Processes and Determination

    • Cells undergo mitosis, movement, and selective adhesion.
    • Programmed cell death plays an important role.
    • Induction, determination, and differentiation processes lead to the specialization and diversification of cell fates.

    Recap of Theme 5:

    • Homeostasis is the process that allows an organism to maintain a consistent or otherwise stable internal environment
    • Asexual reproduction involves one parent; the offspring are largely identical to the parent organism, while sexual reproduction involves two parents to increase genetic diversity
    • Fertilization is the union of sperm and egg (gametes) to form a zygote.
    • Internal fertilization often requires specialized organs for efficient mating, and external fertilization occurs in aquatic environments
    • The three germ layers, ectoderm, mesoderm, and endoderm, are formed through a series of developmental steps
    • Pattern formation establishes major body axes
    • Organogenesis forms major organ rudiments.

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    Theme 3-5 A - Terrestrial Animals PDF

    Description

    Test your knowledge on the mechanisms of gas exchange and homeostasis in aquatic animals. This quiz covers adaptations like endo- and exoskeletons, the challenges faced in aquatic environments, and unique physiological traits of marine mammals. Dive into the fascinating world of aquatic biology and learn how these animals thrive in their habitats.

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