Within the Actinopterygii (bony fish) lineage, marine teleosts (bony fish with mobile jaws) live in an aquatic environment where there is a higher external concentration of salt and a lower concentration of water relative to their internal concentrations.  Owing to these conditions, salt ions tend to diffuse into the teleost through its skin, whereas water molecules within the organism osmotically traverse the opposite path.Irrespective of lineage, many fish species actively assess their environment and regulate their internal concentration of fluids and electrolytes via a homeostatic process known as osmoregulation.  Teleosts with either glomerular kidneys (eg, eels, sculpin) or aglomerular kidneys that are purely tubular (eg, goosefish, toadfish) have served as experimental subjects for the study of marine teleost osmoregulation.  Analyzing the ionic (ie, Na+, Cl−, Mg2+, SO42−) concentration of intestinal fluids, urine, and plasma in each species led to the discovery that the renal tubule of the goosefish has both excretory and reabsorptive functions.Scientists have concluded that marine teleost osmoregulation involves the ingestion of seawater, retrieval of salts and water from the intestine, and primary excretion of divalent ions via urine and monovalent ions through the gills (thin barriers between the organism's blood and the aquatic environment).In an experiment to further study osmoregulatory mechanisms, researchers emptied the gut of an eel and sealed the anus to prevent anal fluid loss.  The eel was transported into seawater that had been treated with the volume marker phenol red, which can only be excreted anally.  After 20 hours, the eel's gut contained 2.3 mL of fluid but showed a phenol red concentration equivalent to 12.3 mL of ingested seawater.  Researchers found that the eel excreted 2.3 g of urine.  They ultimately reported that the eel had lost all the seawater it absorbed through the gut via various mechanisms. Question 55Which of the following conclusions about the eel can be made based on the experiment in the passage?  (Note:  Water density is 1.0 g/mL.)A.The eel absorbed 12.3 mL of water through the gut.B.The eel drank 10.0 mL of water.C.The eel lost 7.7 mL of water extrarenally.D.The eel excreted 4.6 mL of water renally.

What type of osmoregulatory adaptations are usually present in marine vertebrates?Multiple choice question.Adaptations that make them more permeable to waterAdaptations that prevent water from entering their bodiesAdaptations that prevent them from drinking seawaterAdaptations that prevent dehydration

Which of the following is an osmoconformer?a) Freshwater fishb) Sea anemonec) Marine bony fishd) An anadromous fish

What is the type of membrane and fluid for Fish and Amphibia?

In saltwater, the water that surrounds a fish has a higher concentration of dissolved salts than is found in the fish's body cells. Which two methods allow the fish to maintain water balance?A.Releasing large amounts of water in urineB.Pumping out salt through the gillsC.Drinking large amounts of waterD.Absorbing water into the body by osmosisSUBMITarrow_backPREVIOUS

Paragraph 6: In many parts of the ocean where bacteria and krill congregate in high densities tofeed on suspended particulate material, their metabolic activities deplete the water of availableoxygen, thereby creating the oxygen-minimum layer. Those organisms that exploit the detritus inthis layer or feed on other organisms found there must cope with low oxygen levels. The fish, thekrill, and the shrimp associated with this layer characteristically have large gills and blood that ishighly efficient at absorbing any available oxygen. Typically, such animals are also sluggish andadopt an opportunistic policy rather than actively hunting for prey. This way, they conserve energyand reduce their oxygen requirement. Their skeleton and musculature are reduced, and their bodyshape and form is subordinated to the need to remain floating in the water column with theminimum of muscular effort.7. Which of the sentences below best expresses the essential information in the highlightedsentence in the passage? Incorrect choices change the meaning in important ways or leaveout essential information.A: The oxygen-minimum layer occurs where high concentrations of bacteria and knll have depletedthe water of oxygenB: In many parts of the ocean, bacteria and krill gather in high densities to feed on suspendedparticulate matterC: Only krill and bacteria are common in the oxygen-minimum layer, because they need lessoxygen than other organisms.D: High densities of suspended particulate matter exist in the oxygen-minimum layer in many partsof the ocean.8. Which of the following can be inferred from paragraph 6 about predators in theoxygen-minimum layer?A: They are generally stronger than predators in other parts of the oceanB: They generally wait for their prey to come to themC: They spend most of their time swimming around, searching for preyD: They deplete less oxygen from the water than their prey do