OpeningSlide
Today you're goingtodesign yourownAlien!
We'llsplityouupintoteams.
You'lleachchose1of4worldswithintheSolarSystem
Thendesignanaliensuitedtothatenvironment.
Beforeyoustartthough,let'sgetsomeideashowlifemightadapttodifferentenvironment.
Let'stakeEarthasanexamplefirst,sinceit'stheonlyplaceweknowofthatactuallyhaslife!
So,whatmakestheEarth “justright” forlife?
Q:Whatdoeslifehereneedtosurvive?
A:-Air
-Water
-Food
AtmosphereSlide
Air:
AiristhegasofEarth'satmospherewhichisheldinplacebyourplanet'sgravity.
Theatmospherestretchesuptospacegettingthinnerasitgoes.Althoughthere'snorealboundarybetweenouratmosphereandspace,weguessit'saround100km.WecallthistheKármánline.
Butwecanonlybreatheuptoabout8000m.
BreatheSlide
Breathe:
TheatmosphereisveryimportanttolifeonEarth. Space is an airless vacuum so we couldn't breathe there. Thanks to our atmosphere we can breathe on Earth. And notjustoxygen!Asyouknow,plants “breathe” carbondioxideandscientistsfoundanewcreatureatthebottomoftheoceanin2010thatdoesn'tneedoxygentosurviveeither.TherestrangelittlecreaturesarecalledLoriciferaandtheyliveinpartsoftheseawith almost no oxygen.(Scientistsarestilldoingresearchtofindouthowtheysurvive.)
ProtectionSlide
The atmosphere also provides protection from harmful cosmic rays. Like Ultraviolet radiation, X-rays and Gamma rays. The Sun sends lots of UV rays at the Earth (these cause Sunburn!) that we know can be dangerous to humans, they damage our eyes and can cause skin cancer. X-rays and Gamma rays come from the really energetic events in the universe, Supermassive black holes and supernova (the explosive deaths of massive stars) These rays are very damaging to living cells, even deadly!Luckily our atmosphere absorbs most of these rays and stops them reaching the surface!
SmallTemperatureSlide
Temperature:
Theatmosphereisimportantforanotherreason,regulatingthetemperatureontheEarth'ssurface.
Ouratmosphereactslikeablanket.DuringthedayitprotectsusfromtheextremeheatoftheSun.WhileatnightitkeepsoutthechillingcoldofSpace(234.45celcius).Spaceisjustafewdegreeaboveabsolutezerowhichisthelowesttemperaturepossible!
BigTemperatureSlide
Forexample,theMoonisaboutthesamedistanceasEarthfromtheSun.ButthetemperatureontheMoonisverydifferentfromEarth.Althoughthemoondoeshaveanatmosphere,it'snotreallyworthmentioning.Itisextremelythin,veryunstableandbecauseoftheMoon'slowgravityitisconstantlyblowingintospace.
Point to Earth-Moon temperature comparison
ThesearetheextremetemperaturesontheMoonandEarth,lookhowdifferenttheyare!
Q:Sowhatwouldhappenifouratmospherewasthinner?
A:-Wemightneedbiggernostrilstosuckinmoreairatonetime?
-Wewouldneedtobemoreadaptabletotemperaturechange,mayberetractablebodyhair, ortheabilitytoturnyourskinintoamirrorandreflectheat?
-We'dneedthickerskinmadeofastrongermaterialtoprotectusfromcosmicradiation.
Q:Whatwouldhappenifouratmospherewasthicker?
A:-Wemightneedbettervisionorotherwaysof “seeing” throughthefog.
-Itwouldholdheatmuchbetterso,dependingonhowfartheworldisfromtheSun,it maygetquitehot.Maybeitlivesunderwater(ifthereiswater!)
Thisbringsustothenextimportantfeatureofourworld:itsdistancefromtheSun.
WaterSlide
DistancefromtheSun.
Aworld'sdistancefromtheSunisimportantbecauseitaffectsthetemperaturethere,whichdirectlydeterminestheexistenceofanotherkeyfactoroflife – Water.
Everyplanetarysystemhasabandwecall “TheHabitableZone”.Thisistheareaarejusttherightdistanceforliquidwatertoexist – nottoohot,nottoocold.
HabitableZoneSlide
ThisbluebandshowsthehabitablezoneinourSolarSystem,youcanseetheEarthsitscomfortablyinside.Marsisalsointhehabitablezone.
Q.Doesthissurpriseyou?
A.WeknowthatliquidwaterusedtoexistonthesurfaceofMarsformillionsofyears.Andnotjustalittle,theMarsroverCuriosityhasfoundevidenceofdeepriverbedsonMars!
Q.Sowhatmightlifeonaworldwithoutliquidwaterlooklike?
A.Maybeitwouldhavelimbsthatcanmeltice?Maybetheywouldbemakeofrock!
Q.SowhatelselifeonEarthneedbesideairandwater?
A.Food!
FoodZoneSlide
Food:
Plants normally sit at thebottomofthefoodchain.
Q.Whatdoplantsneedtosurvive?
A.SunshineandWater(whichwe'vetalkedabout)
Soil
Skipthroughthreeslidesastalkingaboutthem.
Q.Istheresoilonotherworlds?
A.Yes! SamplesSlide Weevenhavesome!TheastronautsfromApollo11(thatlandedonthemoon)broughtbacksomesoilfromtheMoon!AndweknowMarshassoiltoo.
Q.IfaworldistoofarfromtheSunandhasnosolidsurfacewithsoil,howwillitchangethealienlife?
A.Maybetheywilleatsomethingdifferent,likerocks,andneedBIGSTRONGSHARPteeth,likesteel!Ormaybetheywillliveoffgasintheair,andneedbignostrilstosuckinasmuchaspossible?
GravitySlide
GRAVITY:
Q:Anothersimplequestion:WhatstopsusfromleavingEarth?
A:-Gravity
Youallknowaboutgravityright?ItholdsustotheEarthandstopsusfloatingoffintoSpace.
Youprobablyknowthatgravityisn'tasstrongonthemoon,sopeoplecanjumphigherandfallslower.
Q.Sohowwouldweakerorstrongergravityaffectlifeonanotherworld?
A.-Stronger:Creaturesmightevolvelowertotheground,likesnakesorinsects.
-Weaker:Theremightbemoreflyinganimals,likebirds!Ortheycouldgrowntaller andheavier,likeelephants.
Marsslide
Mars:
Let'sdoanExample.HereissomeinformationaboutMars.
Q.DoesanyonehaveanyideaswhatacreaturefromMarswouldlooklikebasedontheenvironment?
A.VerycoldcomparedtoEarth.
Weakatmosphere:nomuchair.
WeakGravity:creaturelighter,canmoveeasier.
Icewater,butnoknownliquidwater.
Redsurface:camouflage?
Endslide