Name

SquirrelIslands

SquirrelIslands 1

Purpose: To explainhow adaptationshelporganismssurviveindifferent environments

BackgroundInformation: Mutations arerandomchangesinthegeneticinformationof anorganism.Theycause newtraitsinanorganism.Mostareharmful, butafewareneutral oreven beneficial.

Therearetwomaintypesofgeneticmutations:apoint mutationand aframeshiftmutation.Ina point mutation,one ofthebases (chemicals) inthechain ofDNAisreplacedbyadifferent base.In aframeshift mutation,one base pairis"deleted,"

soitthrowsofftheDNAsequence,leading todifferent proteinsthat areusually uselessorharmful.

Abeneficial orneutralmutationcanquicklybecomeharmfulwhentheenvironmentschange. Theenvironmentgreatlyaffectsanorganism’sabilitytosurvive,and even asmallchangecan beharmful tosome organisms.

Someexamples:

!

Thepanda’s"thumb"isactuallyanenlargedboneofthewrist.Inthepanda’senvironment,bambooisthemainfoodsource. Itisdifficult tohandleand breakthehardstalks,soanenlargedwristbonehelpstograspthebamboo.Inanotherenvironmentwherethefoodsourceisnotplants,anextra‘finger’wouldhave little benefit, perhapseven becumbersome.Themutatedhandsofpandashave been beneficial onlybecauseoftheirneedforabettergriponbamboo.

!Thekokapo isastrangeflightlessparrotthat livesinthebrushonthemountainsofNewZealand.Beforeman reachedits shores, theislandwasalmostmammal-free, withnogroundpredatorsofbirds.Asaresult,themanygrounddwellingbirdslost theabilitytofly,becausetherewasnoneed.Theirwings aresmalland useless.Whenmandidcome theybroughtmammals,suchascatsand weasels.Thekokapo waseasypreyforthem, and isnow nearlyextinct.Thishappenedtoseveralother birds,includingthekiwi.Thesebirdsinabilitytoflyquicklycaughtuptothemwhen theenvironmentchanged,showinghow theirmutationofbad wings washarmful inadifferent environment.

Adaptedfrom Rat Islands:Anexplorationinspeciation byLeslie Tong Access Excellence Activities – To – Go

SquirrelIslands 2

!Thepenguinhasasimilarsituation, livinginthewatersofAntarcticaand surroundingplaces.Theyhave evolved intoflightlessbirdsthat

arecumbersomeand ineffectiveonland,butaremasters ofthewater.InAntarctica, theseaisthebestplacetogetfood,sothatiswherethe

penguinhashunted.Ithasgraduallylostits abilitytofly,attainedhugeamounts ofinsulatingblubber,and gainedmutatedlegsthat aregreatforswimmingand terrible forwalking.Ifthepenguinwasnotintheenvironmentitissowellsuited for,itwould beveryvulnerableand helpless.Themutationsthat have helpeditsurviveinAntarcticawould

quicklybecomeuselessinaplacelike thegrasslandsormountains.Inanenvironmentwithout waternearby,mutatedwings and legssuited forswimmingare useless. (InformationfromNatureNiche;

Materials:

DrawingpaperMappencils

Procedure:

1. Workwithyourpartner.

2. Putyournamesonthebackofthedrawing paper.

3. UseaPENCIL

4. Youwillbeassignedanislandhabitat.

5. Design asquirrelthat hasadaptedtotheenvironmentoftheisland

(beneficialmutations).

6. Drawtheislandenvironmentand thesquirrel.

7. Onthebackofyourdrawing,describetheadaptations,and whytheyarebeneficial tothesquirrel.

8. Neatnessand attentiontodetailmatters!

Adaptedfrom Rat Islands:Anexplorationinspeciation byLeslie Tong Access Excellence Activities – To – Go

SquirrelIslands 3

IslandEnvironments:

ISLAND1
ƒFairly flat
ƒFew hills
ƒGroundissoftdirt
ƒSeveral species of small bushes
andshrubsgrow in the center of the island
ƒNo animal life on land; but the water
isfulloffish.
ƒSurrounded by a coral reef which
keepsthepredators out.
ƒSandy beach with no algal growth
ƒFreshwater isavailable. / ISLAND2
ƒRocky shoreline
ƒMany tide pools dot the island along
thebeach
ƒWaveaction issomewhat sheltered
byrockoutcrops.
ƒTide pools contain barnacles,
oysters,sea urchins and crabs
ƒAlgae grows all around theisland,
however,itisquite thininthetide pools where the animals feed
ƒThecurrent isquite strong along the
rockyoutcrops where the algae grows best
ƒFreshwater isavailable.
ISLAND3
ƒDesert-like
ƒA few species of cactus live on the
barerocks
ƒAlarge cactus-eating tortoise lives
onthe island
ƒAspecies ofvery large bird nest on
theisland annually
ƒThey build their nests on the rocks,
andprotecttheireggs from the sun bystanding over thenestswith outspread wings
ƒThe nests are always found on the
windyside of the island which is somewhat cooled byoffshore breezes. / ISLAND4
ƒThe island is an extinctvolcano
ƒPlant life on theisland changes with
thealtitude moving up the volcano
ƒGrassesgrow atthebase.
ƒFurther up the slope the grasses
giveway to low shrubs
ƒHalf way up,theisland becomes
quitelush; tropical plants and trees dominate the landscape
ƒAtthisaltitude, theisland
experiencesfrequent rain showers
ƒThere are two speciesof birds that
liveon the island: One is a raptor (meat-eating) which preys upon the smaller birds.Theotherbird fishes the waters approximately one mile offshore
ƒBothnestintrees.

Adaptedfrom Rat Islands:Anexplorationinspeciation byLeslie Tong Access Excellence Activities – To – Go

SquirrelIslands 4

QuestionsConclusions:

UseChapter17inyourtextbook and your notebookasareference.

1. Giveanexampleofeachofthefollowing inyourSquirrelIslandecosystem:

!Producer

!Consumer

!Predator

!Prey

!Scavenger

!Decomposer

!Habitat

!Community

!Population

!Niche

!Abioticfactor

!Bioticfactor

!Limitingfactor

!Carryingcapacity

Adaptedfrom Rat Islands:Anexplorationinspeciation byLeslie Tong Access Excellence Activities – To – Go