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