Unit4Astronomy:thescienceofthestarsHowLifeBeganontheEarthPeriod1ScienceScienceSubjectsSubjectsPhysicsChemistryBiologyGeologyMathematicsMedicineBiochemistryGeophysicsAstronomyAstronomyAstronomyisthescientificstudyoftheuniverseandtheheavenbodies(suchasthesun,themoon,andstars),gas,anddustwithinit
astronomerastronomerTheBigBangTheBigBangTheSolarsystemTheSolarsystem•eightplanets•manycomets•otherobjectsWaterWaterAirAirLifeLifeWateristheheadspringoflife
Wateristheheadspringoflife
AcloudofdustCombineintoasolidballExplode…withfire&rock(produceH2O,CO2,O2,N2,othergases)atmosphereCooldownwaterappeareddissolveharmfulgasesinto…LifebeganLifedevelopedThedevelopmentoflifeAcloudofdust→asolidball→presenceofwater→onthewater→shellfish&otherfish→plantsbegintogrowondryland→insectsandamphibiansappear→retilesappe