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Feeding Strategies in the cean
In the pen sea, animals can ften find fd reliably available in particular regins r seasns (e g., in castal areas in springtime). In these circumstances, animals are neither cnstrained t get the last calrie ut f their diet nr is energy cnservatin a high pririty. In cntrast, the fd levels in the deeper layers f the cean are greatly reduced, and the energy cnstraints n the animals are much mre severe T survive at thse levels, animals must maximize their energy input, finding and eating whatever ptential fd surce may be present.
In the near-surface layers, there are many large, fast carnivres as well as an immense variety f planktnic animals, which feed n planktn (small, free-flating plants r animals) by filtering them frm currents f water that pass thrugh a specialized anatmical structure These filter-feeders thrive in the well-illuminated surface waters because ceans have s many very small rganisms, frm bacteria t large algae t larval crustaceans. Even fishes can becme successful filter-feeders in sme circumstances Althugh the vast majrity f marine fishes are carnivres, in near-surface regins f high prductivity the cncentratins f larger phytplanktn (the plant cmpnent f planktn) are sufficient t supprt huge ppulatins f filter-feeding sardines and anchvies. These small fishes use their gill filaments t strain ut the algae that dminate such areas. Sardines and anchvies prvide the basis fr huge cmmercial fisheries as well as a fd resurce fr large numbers f lcal carnivres, particularly seabirds. At a much larger scale, baleen whales and whale sharks are als efficient filter-feeders in prductive castal r plar waters, althugh their filtered particles cmprise small animals such as cpepds and krill rather than phytplanktn.
Filtering seawater fr its particulate nutritinal cntent can be an energetically demanding methd f feeding, particularly when the current f water t be filtered has t be generated by the rganism itself, as is the case fr all planktnic animals. Particulate rganic matter f at least 2.5 micrgrams per cubic liter is required t prvide a filter-feeding planktnic rganism with a net energy gain This value is easily exceeded in mst castal waters, but in the deep sea, the levels f rganic matter range frm next t nthing t arund 7 micrgrams per cubic liter. Even thugh mean levels may mask much higher lcal cncentratins, it is still the case that many deep-sea animals are expsed t cnditins in which a nrmal filter-feeder wuld starve
There are, therefre, fewer successful filter-feeders in deep water, and sme f thse that are there have larger filtering systems t cpe with the scarcity f particles. Anther slutin fr such animals is t frage in particular layers f water where the particles may be mre cncentrated. Many f the grups f animals that typify the filter-feeding lifestyle in shallw water have deep-sea representatives that have becme predatry. Their filtering systems, which reach such a high degree f develpment in shallw- water species, are greatly reduced. Alternative methds f active r passive prey capture have been evlved, including trapping and seizing prey, entangling prey, and sticky tentacles.
In the deeper waters f the ceans, there is a much greater tendency fr animals t await the arrival f fd particles r prey rather than t search them ut actively (thus minimizing energy expenditure). This has resulted in a mre stealthy style f feeding, with the cnsequent emphasis n lures and/r the evlutin f elngated appendages that increase the active vlume f water cntrlled r mnitred by the animal. Anther cnsequence f the limited availability f prey is that many animals have develped ways f cping with much larger fd particles, relative t their wn bdy size, than the equivalent shallwer species can prcess. Amng the fishes there is a tendency fr the teeth and jaws t becme appreciably enlarged. In such creatures, nt nly are the teeth hugely enlarged and/r the jaws elngated but the size f the muth pening may be greatly increased by making the jaw articulatins s flexible that they can be effectively dislcated. Very large r lng teeth prvide almst n rm fr cutting the prey int a cnvenient size fr swallwing, the fish must gulp the prey dwn whle.
1.The wrd "severe" in the passage is clsest in meaning t
extreme
cmplex
basic
immediate
2. What can be inferred frm paragraph 1 abut why energy cnservatin is nt a high pririty fr cean animals in castal waters during the spring?
Thse animals are least active during the spring
Thse animals have a plentiful supply f fd
Thse animals have t expend energy t avid predatrs.
Thse animals stre energy during the clder seasns.
3. What can be inferred frm paragraph 2 abut fish?
Mst fish feed n planktn.
Fish tend t avid well-illuminated areas.
Mst fish species are nt filter-feeders.
Few fish species are successful in the near-surface layers.
4. Accrding t paragraph 2, hw d sardines and anchvies btain fd near the surface f the cean?
They rely n the large quantities f fd resurces als available t lcal carnivres.
They capture the larvae f sme crustaceans.
They feed n the rganisms left ver by cmmercial fisheries.
They btain algae by using their gills as filters.
5. In paragraph 1, the authr cmpares pllen mved by wind with letters thrwn ff rfs in rder t
explain why there are relatively few species f trees that depend n wind pllinatin
cmpare natural, bilgical prcesses with human scial practices
make a pint abut the prbability f wind-blwn pllen reaching a tree f the same species
argue against the cmmn assumptin that the tallest trees are the mst likely t emply wind pllinatin
6. Paragraph 2 suggests that wind-pllinated plants d nt have bright petals, nectar, and scent fr which TW f the fllwing reasns? T receive credit, yu must select TW answers.
They interfere with pllinatin by wind
They are easily damaged by wind.
They are unnecessary.
They reduce the amunt f pllen that can be prduced.
7. The wrd "scarcity" in the passage is clsest in meaning t
speed
variety
lack
size
8. Accrding t paragraph 4,deep-water filter-feeders have adpted all f the fllwing ways t btain fd EXCEPT
develping larger filtering systems
capturing prey using sticky tentacles
swimming up t the surface at feeding time
searching in cean layers that cntain a substantial amunt f particles
9. Why des the authr include the infrmatin that animals in the deep cean place an emphasis n lures" and have evlved "elngated appendages”?
T argue against the view that animals in the deep cean use mre energy t find fd than d animals in shallw waters
T emphasize the imprtance f an am mars ability t cntrl a large vlume f water
T identify sme feeding strategies that animals have develped t minimize their energy expenditure
T give examples f bdy structures that help thse animals mve quickly in deep cean waters
10. The phrase "cping with" in the passage is clsest in meaning t
Absrbing
finding
appraching
managing
11. The wrd "flexible" in the passage is clsest in meaning t
huge
adaptable
pwerful
precise
12. Accrding t paragraph 5, why d sme fish swallw their prey whle?
Their teeth are t large t allw fr cutting prey.
They have n jaw muscles t allw chewing.
Swallwing prey whle results in a higher net energy gain.
Chewing can cause their jaws t dislcate.
13. Lk at the fur squares [] that indicate where the fllwing sentence culd be added t the passage.
Such a passive apprach requires thse animals t develp specialized methds f acquiring fd.
Where wuld the sentence best fit? Click n a square [] t add the sentence t the passage.
14. Directins: An intrductry sentence fr a brief summary f the passage is prvided belw Cmplete the summary by selecting the THREE answer chices that express the mst imprtant ideas in the passage Sme sentences d nt belng in the summary because they express ideas that are nt presented in the passage r are minr ideas in the passage This questin is wrth 2 pints.
Drag yur answer chices t the spaces where they belng. T remve an answer chice, click n it.
T review the passage, click VIEW TEXT
cean animals have develped varius strategies fr maximizing energy input frm fd.
Answer Chices
Large carnivres near the cean surface feed mainly n rganic matter left ver after it passes thrugh the filters f the filter-feeders.
Even in deep cean layers where prey is relatively hard t find, filter feeding is still the least energetically-demanding methd f btaining fd.
Animals in deeper water have evlved strategies and bdy structures that allw them t use as little energy as pssible in btaining fd.
Near the surface f the water, many animals btain fd by using specialized bdy parts t filter planktn frm the water.
Filter-feeding is mre cmmn in shallw water, where there is a higher cncentratin f rganic matter than there is in deeper water.
At deeper cean levels planktn is relatively rare, requiring animals at thse levels t actively search fr their fd surces.