原版英语RAZ 教案(Z1) Symbiotic Wildlife.pdf

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1、Visit www.readinga- for thousands of books and materials.WritingImagine you are a scientist studying the ocean.What symbiotic relationships would you see?Write a journal entry detailing your discovery.ScienceChoose and research one symbiotic relationship from the book or another source.Write a repor

2、t that includes details about both species and their partnership.ConnectionsSymbiotic WildlifeA Reading AZ Level Z1 Leveled BookWord Count:2,469www.readinga-LEVELED BOOK Z1Symbiotic WildlifeZZ1Z2Written by M.T.Stark www.readinga-How do symbiotic relationships work,and why are they important?Focus Qu

3、estionSymbiotic WildlifeWritten by M.T.StarkCorrelationLEVEL Z1WXN/A60Fountas&PinnellReading RecoveryDRASymbiotic WildlifeLevel Z1 Leveled Book Learning AZWritten by M.T.StarkAll rights reserved.www.readinga-Front cover:A yellow-billed oxpecker positions itself on the neck of an impala before cleani

4、ng its ears.Title page:A greater short-nosed fruit bat feeds on a banana plant.The banana is a bat-dependent plant.Pollen is carried on the bats fur to other banana plants,allowing them to reproduce.Page 3:A school of yellow tang fish clean the algae from a green sea turtle.Photo Credits:Front cover

5、:Pete Oxford/Minden Pictures;title page:Merlin Tuttle/BCI/Photo Researchers,Inc.;page 3:Masa Ushioda/age fotostock/SuperStock;page 4:Juniors Bildarchiv/Alamy;page 5:iStock/Kristian Sekulic;page 6:John Pavel/D;page 7:iStock/Derek Holzapfel;page 8:Alexandr Shestopalets/D;pages 9(top),11(top),12:iStock

6、/Diane Labombarbe;page 9(bottom):Richard T Nowitz/C/DAMON/age fotostock;page 10:Jamesdawson/D;page 11(bottom):Tui De Roy/Minden Pictures;page 13:Salpics32/D;page 14:Reinhard Dirscherl/Alamy;page 15(main):Dave Parker/D;page 15(inset):Rafael Angel Irusta Machin/D;page 16:Carol Buchanan/D;page 17:Richa

7、rd Du Toit/Minden Pictures;page 18:Rolf Nussbaumer Photography/Alamy;page 19:Lorand Schuller/D;page 20:Melinda Podor/Alamy;page 21(main):Juniors Bildarchiv/Alamy;page 21(inset):Gerry Bishop/Visuals Unlimited,Inc.;page 22(main):Ralf Broskvar/D;page 22(inset):Frans Lanting/National Geographic Stock;pa

8、ge 23:Steffen Foerster/Dassumesfertilizedinterdependentintimidating mucus nocturnal parasites refugespeciessustainabilitysymbioticvenomousWords to Know3Table of ContentsIntroduction .4Finding Food and Giving Protection .7Helping with Personal Hygiene .10Sharing a Home .12Teaming Up to Find Food .15H

9、itching a Ride .16Pollinating and Fertilizing .18Spreading Seeds .20Conclusion .22Glossary .24Symbiotic Wildlife Level Z14IntroductionLiving in the wild is challenging.Food can be scarce,good homes are hard to find,and pests arewell,pests.Plus,theres almost always something out to eat you.Those reas

10、ons are why many species in the wild form unusual relationships in which they work together at separate tasks that benefit each other.For example,one may offer safety from predators in exchange for a good cleaning or a steady supply of food.Such partnerships are called symbiotic relationships.The wo

11、rd symbiosis comes from the ancient Greek words for“with”and“living.”Scientists first applied the word to wild species in 1877 while writing about lichenscomplex(and sometimes colorful)organisms typically made up of a fungus and a type of algae that work and live closely together.A crocodile opens w

12、ide for a small Egyptian plover bird.The plover cleans bits of leftover food from the crocs teeth.5Since then,scientists have identified symbiotic relationships that exist all around usin deep oceans and dry deserts as well as in mountains and forests.Researchers have discovered unexpected partnersh

13、ips,such as between a venomous sea anemone(uh-NEM-uh-nee)and a colorful clownfish,or a towering tree and a ground-dwelling rodent.In the wild,these unusual partnerships are not only fascinating but can also mean the difference between life and death for the species involved.Bees,for instance,would h

14、ave a hard time surviving without the nectar of flowers and,similarly,those same flowers would have a tough time reproducing without the help of bees that distribute their pollen.Pals and PartnersYou may have your own symbiotic relationship at home.Your pet dog,for instance,provides you with love,co

15、mpanionship,and protection.In return,your dog gets food,attention,and a safe place to live.You both benefit.Symbiotic Wildlife Level Z16Symbiotic relationships arent always equal,but those that have endured over thousands or even millions of years tend to last for one reason:both species benefit eno

16、ugh to make the relationship worthwhile.Some scientists believe that these symbiotic relationshipswith different species interdependent on one anotherare a big reason we have so many diverse plants and so much diverse wildlife on Earth.Lets look at some examples of the many types of symbiotic relati

17、onships to see how different kinds of living things work together in the natural world.A group of starlings stick close to a red deer for the chance to pick insects off its body.Word WiseThe partners in a symbiotic relationship are called symbionts.7Finding Food and Giving ProtectionSometimes its ni

18、ce to know someones got your back.Clownfish,such as the colorful ones that live in the Indian Ocean,need all the help they can get to stay safe from predators.One way they do this is by seeking refuge in the tentacles of venomous sea anemones.Although anemones look like plants,theyre actually marine

19、 animals that attach themselves to rocks or other surfaces and then wait for prey to come to them.When small fish or shrimp brush against an anemones soft tentacles,they are exposed to a toxin.The toxin paralyzes them long enough for the anemone to pull them to its mouth and eat them.Anemones have a

20、 different relationship with clownfish,though.Clownfish have figured out a way to build up immunity to the anemones venom.They do this by touching the anemones tentacles once or twice,taking a break,and then doing it again and again.This repetition gradually provides the clownfish with a protective

21、layer of mucus on its skin.Sea anemoneSymbiotic Wildlife Level Z18The mucus shields the clownfish from any harmful contact with the anemone and allows the fish to swim among the anemones tentacles without getting hurt.So,when a predator arrives to have a clownfish for lunch,the clownfish can dive in

22、to the safe arms of the anemone.When the predatory fish gets too close to the anemone,the anemones stinging cluster of tentacles kill it and provide a meal for both members of this partnership.A cautious striped clownfish hides from predators among the protective tentacles of a venomous sea anemone.

23、9In Africa,ostriches and zebras often feed together and use their combined sensory strengths to help keep each other safe from predators.Ostriches have good eyesight,and zebras have excellent hearing.Together,the two species have a much better chance of detecting a stalking lion or other predator on

24、 the prowl than they do alone,which helps them get a head start on escaping to safety.Africas impalas and baboons have a similar relationship.Impalas have superb hearing,sight,and sense of smell.If they detect danger first,their alert body language and horn shaking warn the baboons to beware.The bab

25、oons then sound the alarm,using their loud screams and intimidating teeth to scare predators away.AfricaIN D I A N O CE A NAT L A N T IC O CE A NGroups of ostriches and zebras often feed together and warn each other if they detect approaching predators.EuropeSymbiotic Wildlife Level Z110Helping with

26、 Personal HygieneSome animals need a friends help to clean those hard-to-reach places.On many ocean reefs,a silvery little fish called a cleaner wrasse provides just such a service.The tiny wrasse sets up a“cleaning station,”and large fish,such as angelfish or butterflyfish,wait patiently for their

27、turn.So why doesnt the larger fish just eat the wrasse?Its because the wrasse has developed a certain way of swimmingsome have described it as a sort of“hypnotic dance”that calms the larger fish and eventually leads it to open its mouth to let the wrasse inside.The wrasse then darts in and out of th

28、e larger fishs mouth and gills,clearing them of fungus,parasites,dead skin,and other debris.The wrasse gets a snack and leaves the larger fish clean and healthy.A giant moray eel has its teeth and mouth cleaned by a bluestreak cleaner wrasse.11Some of Darwins ground finches provide a similar cleanin

29、g service to tortoises on the Galapagos Islands.When a tortoise is ready for cleaning,it assumes a particular posture,extending its neck and legs so that a neighboring group of ground finches can swoop in and peck away at parasites that the tortoise is unable to reach.The tortoise stands absolutely

30、still as the finches do their work.The finches get fuller stomachs,and the tortoise leaves cleaner than before.Darwins ground finches cling to the neck and legs of a giant tortoise as they pick ticks from its body.GALAPAGOS ISLANDSSouth AmericaNorth AmericaPAC I F I C O C E A NAT L A N T I C O C E A

31、 NSymbiotic Wildlife Level Z112Sharing a HomeSharing a home can be tricky,especially when its with a species thats nothing like you.Two of natures most improbable roommates live on the high shoreline cliffs of New Zealand.One of them is a slow-moving,lizardlike reptile called a tuatara(too-uh-TARR-u

32、h),which usually cant be bothered to build its own nest.The other is a fast-flying bird called a sooty shearwater.The two species share a home,but not at the same time.The tuatara is nocturnal,so it usually spends the day in the burrow and goes out at night.When home,it performs housecleaning duties

33、 by eating the burrow bugs and parasites that annoy the shearwater.While the tuatara is performing its housecleaning duties,the sooty shearwater hunts.The shearwater returns to the shared burrow at night,loosening the burrow dirt and producing droppings that attract insects that the tuatara loves to

34、 eat.Its a perfect arrangement for this odd couple.Although they rarely see each other,they share both a home and a welcome partnership.NEW ZEALANDAustraliaPA C I F I C O C E A NI N D I A N O C E A NAsia13Burrowing owls,the smallest owls in North America,make great neighbors.They cant actually dig h

35、oles,but they do use them as safe places to hide from predators.Because of their small size,the owls are a perfect fit for abandoned burrows that were once home to prairie dogs or gopher tortoises.When a tiny owl chooses an empty burrow,the former occupant may have relocated to the burrow next door.

36、Each animal helps the other by sounding a warning if a predator approaches.Forest mice and burrow beetles also have a home-sharing arrangement that benefits both species.While the mouse sleeps in the burrow,the beetle roots through the mouses fur,snacking on fleas.When the mouse is away,the beetle s

37、cours their home for other burrow bugs.The beetle eats well,and the mouse gets a pest-free home.The tiny burrowing owl builds its nest underground in abandoned burrows.It warns neighbors of approaching predators.Symbiotic Wildlife Level Z114Some ocean animals share homes as well.Survival is the goal

38、 of all animal species,but it can be hard to survive when you cant see danger.Thats the plight of snapping shrimp,which live on the ocean floor.The near-blind shrimp dig burrows into the seabed.As they move sand to build their homes,the shrimp are at risk of being eaten by hungry predators.Fortunate

39、ly,the shrimp have a clever partner that can easily spot troublethe alert and sharp-sighted goby fish.As shrimp dig in the sand,goby fish hover nearby and act as lookouts.When danger appears,the fish flick their tails,touching the shrimps antennae and sending a signal to the shrimp that theyd better

40、 take cover.In return,the shrimp share their burrows with the goby fish.The fish have a safe place to sleep at night as well as a convenient place to hide.Its a perfect partnership for these symbiotic sea dwellers.A goby fish and a snapping shrimp team up to build a home.15Teaming Up to Find FoodHig

41、h in Americas Rocky Mountains,grizzly bears,red squirrels,and white bark pine trees are part of a cycle that helps them thrive.The pine trees provide pine nuts,a high-calorie food source for both bears and squirrels.Red squirrels eat some of the nuts and bury others to eat later.The bears strong sen

42、se of smell helps them locate and consume the buried pine nuts.The droppings that the bears leave behind after digesting the nuts distribute some of the tree seeds,which causes new trees to sprout and grow.The new trees will eventually provide even more pine nuts for future generations of both bears

43、 and red squirrels.The huge grizzly bear and the small red squirrel depend on each other and nuts from the white pine tree to maintain a healthy diet.Symbiotic Wildlife Level Z116Hitching a RideMost small fish wisely keep their distance from sharks.A slender fish called a remora,though,does everythi

44、ng it can to get up close and personal with sharks.In fact,each remora has a flat,ribbed disc on the top of its head that functions as a suction cup to help the fish attach itself to the underside of a shark.Remoras are capable of swimming on their own,and they often do,but hitching a ride on a shar

45、k or other large creature is sometimes just an easier and more efficient way to get around.Once attached,a remora goes everywhere the shark hunts and feeds,eating any scraps of food that escape the sharks powerful jaws.The remoras provide a service,too,consuming parasitic hitchhikers and helping to

46、keep their host animals clean.A small remora fish(arrow)attaches itself to a sharks belly to travel with it and share its meals.17Remoras arent the only creatures with strange things on their heads.Some hermit crabs that live in the Mediterranean Sea wear an odd-looking hat.The hat is actually a hit

47、chhiking sea anemone.The sea anemones long tentacles are venomous,but the hermit crab is protected from them by its hard shell.The anemone protects the hermit crab from predators.In exchange,the anemone benefits from the crabs messy habits when it eats scraps of food that the crab doesnt eat.Not all

48、 symbiotic hitchhikers are in the sea.In Africa,a small bird called an oxpecker often hitches a ride on the back of a hippopotamus instead of exerting energy searching for insects on its own.The bird picks bugs off the skin of the hippo and eats them.The oxpecker gets a meal and easy transport,and t

49、he hippo gets picked clean of pesky insects.A group of oxpecker birds hitch a ride on the back of a hippopotamus.In return for the ride,they pick the hippo clean of bugs.Symbiotic Wildlife Level Z118Pollinating and FertilizingBats do more than just inspire spooky stories.For many plants around the w

50、orld,bats are their ticket to survival.In return,those plants provide sweet nutrition for their furry,winged friends.Bats are part of an important group of animals called pollinators.These animals transport pollen from the stamens,or male parts of flowers,to the pistils,or female parts,as they eat,a