Exam III Terrestrial biomes Precipitation and temperatures determine biomes Biomes of the world 1 4 are terrestrial biomes 1 Desert 2 Tundra 3 Forests tropical temperate taiga 4 Grassland 5 Aquatic marine and freshwater Desert Hot dry Semiarid Coastal Cold Characterized by extreme dryness Hot and dry deserts Arizona is located in the Sonoran Desert Celsius to Fahrenheit multiply by 9 divide by 5 then add 32 Hot and dry deserts Plant adaptations Canopy in most deserts is very rare Mainly ground hugging shrubs and short woody trees Leaves have water conserving characteristics In the cacti the leaves are reduced to spines Hot and dry deserts Animal adaptations Animals include small nocturnal carnivores Many are burrowers and endothermic An endotherm is an animal that produces most of its own heat metabolically Insects arachnids reptiles and birds Animals stay inactive and hidden during the hot day but come out at dusk dawn or night when the desert is cooler Tundra coldest biome Arctic and mountain regions Low growing vegetation and permafrost Frost molded landscapes extremely low temps little precipitation poor nutrients and short growing seasons Dead organic material acts as a nutrient pool major nutrients nitrogen and phosphorus Arctic tundra Northern hemisphere Low biodiversity Simple vegetation structure Soil is formed slowly due to permafrost consisting mainly of gravel and finer material No deep root systems About 1 700 kinds of plants in the arctic and subarctic Adapted to sweeping winds and disturbances of the soil Animals adapted to handle long cold winters and to breed and raise young quickly in summer Mammals and birds have additional insulation from fat Many animals hibernate during the winter Birds may migrate south in the winter Reptiles and amphibians are few or absent Forests Occupy about 1 3 of Earth s land area Account for over 2 3 of the leaf area of land plants Contain about 70 of carbon present in living things Low growing vegetation and dominated by trees and other woody vegetation Three major forest types tropical temperate boreal taiga Tropical forests Greatest diversity of species They occupy near the Equator Distinct seasonality winter is absent and only two seasons are present rainy and dry 12 daily hours of daylight with little variation Temperate forests Occur in eastern North America NE Asia and western and central Europe Moderate climate and a growing season of 140 200 days during 4 6 frost free months Boreal forests Largest terrestrial biome Seasons are divided into short moist and moderately warm summers and long cold dry winters Precipitation is primarily in the form of snow 40 100 cm annually Grassland biome of Earth s land surface Large open spaces between forests and deserts Many types of grass few trees Plant species composition depends on humidity and temperature Temperate and tropical grasslands Prairie and steppe Savanna Aquatic biome Largest part of biosphere covers 75 of Earth s surface Can be broken down into two basic regions freshwater i e pond rivers lakes and wetbacks and marine i e oceans estuaries and coral reefs Shaped primarily by the physical characteristics of their environment Salt content Water temperature Water depth Speed of water flow Can be divided into ecological zones defined by Nearness to the shore Water depth Depth to which light penetrates The bottom surface of any body of water is classified as benthic zone Freshwater Ponds lakes streams rivers and wetlands Freshwater is defined as having a low salt concentration usually less than 1 Plants and animals in freshwater regions are adjusted to the low salt content and wouldn t be able to survive in areas of high salt concen Marine of the Earth Layers of marine life Seaweed Phytoplankton Zooplankton Marine Estuaries Where rivers flow into the ocean Constant ebb flow of fresh salt water One of the most productive ecosystems on our planet Marine Coral Reefs made of calcium carbonate secreted by corals need relatively warm clear water Diffusion atoms molecules move from higher to lower concentrations Osmosis diffusion of water through a semipermeable membrane Hypertonic less water on the inside more water on the outside Isotonic equal balance on both sides Hypotonic more water on inside causing it to burst Basic parts of complex land plants 3 vegetative organs root stem leafs Primary tissues vs Primary meristems Vascular tissue procambium Ground tissue ground meristem Epidermis Protoderm Ground Tissue parenchyma most abundant spherical cells have thin flexible cell walls large central vacuole fluid sap collenchyma long cells that can stretch while providing strength and support tube like strands sclerenchyma walls are thin and rigid die at maturity Dermal Tissues epidermis flattened cells covering all parts of plants fit together like a puzzle produce waxy cuticle that helps prevent water loss Vascular tissues transport food Xylem transport water dissolve minerals for the root to the rest of the plant Phloem tubular cells joined end to end photosynthesis Stem internal structure circular arrangement of vascular tissues within a surrounding mass of parenchyma tissue stores sugars Transpiration loss of water through the stoma What causes water and nutrients to travel up the xylem Osmosis pull theory this increases osmotic concentration inside leaf cells water molecules from xylem move into leaf cells via osmosis Tension created pulls on the water column in the leaf xylem Leaf water column pulls upward on the stem water column which then pulls on the root water column Water moves into the roots and root xylem primarily due to osmosis How do land plants regulate water loss Stomata sing Stoma openings in leaf tissue that control the exchange of gases found on green stems and on surfaces of leaves Guard cells control the opening and closing of the stomata by changing shape regulates the flow of water vapor from leaf tissues How Guard Cells Work Guard are the only epidermal cells with chloroplasts In daylight when the stomata opens so CO2 can enter leaf Chloroplasts make sugars photosynthesis Guard cell actively pump K ions How do sugars move through phloem Water moves up xylem Sugars move down phloem What causes climate Climate includes temperature precipitation atmospheric circulation atmospheric chemistry It is measured over a period of several seasons to decades The Earth s tilt of the axis causes it to be warmer in the summer than the winter Why does it become cooler when we