Class amphibia!The amphibians – First vertebrates to inhabit landStill live part of life in water – MetamorphosisAprx. 5,000 species!Characteristics – Moist skin for gas exchange – Ectothermic – Larval stage • metamorphosis
Movement from water to land What does it take to move from water to land? What has to change?
Transition from water to landLiving on land brings different challenges– Example: movement.Amphibians are tetrapods:– “four footed: two sets of paired appendages that are modified as legs that can support the animal.Lungs to avoid drying out.
Adaptations = land livingNew adaptations forliving on land– Lungs– Ears– Four limbs with feet and digits
CHARACTERISTICSEctothermic– Regulate temperature from outside sources. • Basking in the sun • Water temperatureVs. EndothermicWhat would be theadvantages of both?
Ectothermic: AdvantagesSlow Metabolism– Eat lessMust self warmblood enough to beactiveNot enough energyfor continued hardwork
CHARACTERISTICSRespiration: Porous skin– Allow for gas exchange (breathing)– Must live in moist environments to avoid drying outSensitive to chemicals inthe environmentSalamanders do not have lungs andmust breath through skin
REPRODUCTIONInternal sexual reproductionLay 100s of eggs– Advantage of over population of offspring?