Transcript biomes3
Biomes 3 Chaparral • Mediterranean climates - mild winters, dry summers • Thin, nonfertile soil • LOTS OF FIRES • Well adapted; dry leaves, small, tough, scrappy design • Certainly not green and fluffy and lush Savanna: More grasslands • Tropical, flat with scattered height (trees) • Usually acacia trees, well adapted against herbivores • Found where temps are constant and little rainfall • Seasons dictated by amount of rainfall as temps don’t vary • More than just Africa, Australia, S. America • Greatest assemblage of herbivores in world found in this biome – wildebeest, antelope, giraffe, zebra, elephant, hippo, rhino, etc. – Called ungulates, or game animals • This in turn supports large biomass of carnivores – lions, hyena, crocodiles, etc • Due to seasonal rainfall herds migrate • Rapidly being converted to rangeland for livestock African Savannah Tropical Rainforests • • • • Need high temps and constant rainfall 80-180 inches year!!!! Most caused by trees themselves - transpiration Surprisingly poor soils – Leached by rains – Organic litter and detritus absorbed by roots – So nutrients in vegetation, not in soils • Astoundingly high diversity • So much we don’t know; indiginous people can help here • Chemical prospecting – Big agenda at Rio Summit • Industrialization; logging, land conversion all disturbing and widespread • Large amounts of deforestation used for? – Clearing for cattle – Beef industry for fast food burgers – Have to keep clearing, as stripped soil not good for long • Vegetation usually evergreen, with shallow root systems to soak up all decay and water • Huge insect, reptile and amphibian populations • Cold blooded organisms rule!!!! • Biomass above includes birds, and mammals – herbivores and carnivores – Primates • Orangutangs of Borneo • Deserts • • • • • • • Arid = low water content in atmosphere This means wide daily temperature range Usually less than 10 inches of rain/year Desert soil low in organics High in minerals Low plant diversity - soil often exposed Well adapted for drought; cuticle, reduced or no leaves, pulpy interiors • • • • Allelopathy = toxic secretions Inhibits establishment of nearby plants All for one and one for all!!! Well adapted against predation given food deficient environment • Desert mammals tend to be small, nocturnal, and drought adapted – Kangaroo rat - never drinks water!!! – Kangaroos as well require little water • Reptiles thrive here - lizards, snakes, etc. Water Biomes • Different in all aspects!!!! • Terrestrial biomes limiting factors? – Temperature – Precipitation • Certainly not a big deal here Rivers and Streams • Called riparian communities • Current flow rate biggest limitation • adaptations required? – Suckers – Streamlined body shape • Human interference? – Dams – pollution Lakes and Ponds • Littoral = shallow area along shore – Most productive part. Why? – Rooted land plants – Lots of animals • Frogs, worms, insect larvae, fish • Limnetic zone = photic zone away from shore – Lots of plankton – Fish come and go • Profundal zone = below limnetic zone – – – – Deep water Limited photosynthesis Lots of decomposition Bottom water high in nutrients Estuaries • Where freshwater meets the sea • Usually enclosed a bit by land • Enormous productivity - most fertile in world!!! – Tidal action – Land plus marine plants – Runoff from rivers = lots of nutrients • Salinity limiting factor for organisms – Narrow habitat ranges due to osmosis • Also called salt marshes – Highly developed; Redwood Shores for example Marine Zones • Marine is different from aquatic!!!! • Intertidal = land meets sea • Can be sandy (beach), rocky (tidepools), muddy (mudflats, eg. Hayward ) • High human pressures • Incredible adaptations seen here – Pull of tides and currents • Suckers, glue, attachment – Smashing of waves • Curved shells Intertidal continued • If nonmotile (= sessile), adaptations to drying needed • If a sandy beach you are a burrower • If a rocky shore you are a clinger True Oceanic • Pelagic = open water – Subdivisions • photic zone = where sunlight penetrates • Neritic = to a depth of 200 meters (650 feet) • Abyssal = dark, deep waters • Benthic = bottom of the ocean