BIO SCI 152 1st Edition Lecture 12Learning ObjectivesAfter suitable revision, you should be able to -- Define and use the terms below in correct context - Recognize the ecological importance of plants as photoautotrophs - Know how plants form the basis of habitats and biomes - Know examples of plant adaptations found in the different ecosystem types VocabularyPhotoautotroph Deciduous TundraBiome Temperate perennialCarbon fixation Tropical rainforestXerophytic / xerophytesCarbon cycle Epiphyte ChapparalCoal Savanna GrasslandsPeat Drought PrairieFossil fuel Grasses SteppesCarboniferous Bulbous plants TaigaAdaptation AnnualSucculent leaves ConiferPhotoautotrophs photo = light,autotroph Gk. autos = selftrophos = feederPlants balance atmospheric gases - Ameliorate pollution Counteract the greenhouse effect (rising CO2 concentrations in the atmosphere)Supply O2 for us, and other heterotrophs, to breatheImportance of Plants• Photoautotrophs: • Major link in local and global carbon, water and nutrient cycles • Plants are the base of the food chain and source of food for other animals(including humans) • Convert atmospheric carbon (CO2) into organic matter (plant tissue) andOxygen (O2 ) • Without plants there would be no O2, meaning…Fig. 45.6Aquatic macroalgae and phytoplankton contribute 40%of global photosynthesisFig. 46.10Coal FormationDead Plants accumulate in marshy or boggy habitatsIn low oxygen, organic matter decays only partially forming peatUnder heat and pressure, peat becomes coalFossil fuels- produced from deposits of plant remains, chiefly laid down during the Carboniferous period, transformed over millions of yearsEcological Importance of Plants• Photoautotrophs – balance atmospheric gases, global carbon and nutrient cycles• Fix carbon dioxide into organic matter for ingestion by heterotrophs,wood, hydrocarbons (fossil fuels) • Form the basis of habitats for all other organisms – types of ecosystems arenamed after dominant plantsBiomes – Major community types are named after their dominant plants Fig. 42.11Plants can determine the other organisms that live with them: plants provide food and shelter, and modify the environmentBiomes – Major Community Types• Biomes – the major types of communities and ecosystems of plants andanimals that are typical of broad geographic regions • No sharp boundaries, one biome grades into another, • May be patchiness within a biome • Boundaries may be changing with climate change http://www.ucmp.berkeley.edu/glossary/gloss5/biome/ - the Biomes PageWhat determines terrestrial biomes?• Strongly influenced by climate o Rainfall (precipitation)o Temperature (strongly influenced by latitude & altitude)o Evapotranspiration - water transferred from the earth's surface to the atmosphere, including transpirationfrom plants • Geology • Human (anthropogenic) activitiesWithin Biomes, We Often Find Specific Plant AdaptationsBiomes have different resourcelimitations- Temperature (e.g. markedseasons) - Light - Water In Class exerciseTropical RainforestForest floor vegetation sparse – low lightEpiphytes and lianas common – adaptation of growth form to compete with trees for light; Depend on other plants for mechanical support – get up higher in canopyBroad-leafed tropical rainforest plants• Capture light in low-light environments under tall forest canopy Savanna (Tropical grassland)• Found on the edges of forest • Characterized by marked periods of drought and warm temperatures • Open grassy plains maintained by periodic burning (lightning or anthropogenic)• Trees widely scattered, low-growing with thick bark, small leaves to minimizewater transpiration, deciduous during dry season • Characterized by grasses, bulbous plants and few annuals • Savanna can grade into desert (Africa, N Australia) • Savanna can grade into forest and grassland (N. America) DesertHigh temperatures during days, cool or cold at nightLittle moisture in air and <10 cm/year rainAnnuals very common• Desert Annuals – complete their lifecycle rapidly within one year • Seeds can survive several years and periods of drought, and germinate rapidlyDesert Perennials • Plants which survive from year to year• Xerophytic adaptations - Tend to be bulbous or succulent, No or few leaves • Often thick waxy cuticle or covered with hairs to reduce water loss and reflectlight Mediterranean Forest (Chaparral)• “Mediterranean” ecosystems • Poor soils but diverse plant life - adaptations Hot, dry summers, cool wet winters• Perennial shrub-dominated community • Dense impenetrable thicket with 80% cover • Canopy height 1- 4 m Temperate Grasslands – Prairies or steppesCan resemble savannasFound where temperatures are colderDryer regions grade into desert,wetter ones into deciduous forestDominated by perennial grasses, perennial herbsFew Trees except in disturbed areasFertile soilsLong grass Prairie – Chiwaukee Prairie, Kenosha Co. WITemperate forestsShort wet summersLong cold wintersSoil usually thin, nutrient-poor, acidic• Dominated by conifers – needle-like leaves• Some deciduous trees • Grades into Tundra at northern latitudes and with greater altitude • Taiga (Boreal Forest) - responsible for annual oscillation in global CO2 concentrations (Arctic) Tundra• Farthest latitude limits of plant growth • Permanent ice or permafrost close to soil surface • Does not support trees or shrubs • Moist because water cannot percolate into soil • No annuals or woody plants • Perennial plants common • Unknown effects of permafrost melting and breakup Summary• Importance of plants as photoautotrophs - balance atmospheric gases, counteract anthropogenic pollution, role in global C cycle- food for other organisms (base of the food web) • Basis of habitats and biomes – the worlds biomes and what plants are found there• Plants adaptation fit the biome – know