2 Scientists believe that plants evolved from an ancestor of green algae (a member of Kingdom Protista).These early plants were similar to today’s mosses (shown through fossil evidence)Were dependent on water for reproduction and to avoid drying out.
3 The Move To Land… The advantage of life on land… More sunlight More CO2More nutrientsThe disadvantage?Water Loss/Drying Out!So, what adaptations did plants develop in order to thrive on land?
4 Adaptations: 1: The Cuticle A waxy covering that prevents water loss 2: Vascular TissueNot every part of a plant is touching water, so tubes transport materials up and down.Xylem: Water up from the rootsPhloem: Sugars down from the leaves.3: Seeds Instead of SporesSpores need water to reproduceSeeds provide an embryo with the food and protection needed for a dry environment.
6 The Bryophytes (Seedless Non-Vascular Plants) LiverwortHornwortCuticle?YesVascular Tissue?NoSo…Stays close to the ground, near waterSeeds?So…reproduces with spores, must be near waterExamples?MossesLiverwortsHornworts
12 The Gymnosperms (Vascular Seed Plants) Cuticle?YesVascular Tissue?Yes (but leaves are reduced to needles to prevent water loss)Seeds?But…they are naked!Males & Female ConesExamples?PineSpruceGingkoMale & Female cone
17 Task: you need to find a way to survive with your feet permanently anchored in cement You CAN’T:Hide frompredatorsSeek a mateWalk to water orfoodChange yourhabitatYou HAVE to:Get necessary nutrientsGet water & oxygenReproduce (your matemay be miles away)Deal with changes in yourenvironment (i.e. dry, wet,hot, cold, dark, light, etc..)