Download FJC: Env Bio 105: Biome Lec Notes (text only)

FJC Environmental Biology 105:
World Biomes Lecture
Seasons
Suns rays hit N hemisphere:
(1) obliquely for ½ of year
(Autumn/Winter: Sep-Mar)
(2) more directly for ½ of year (Spring/Summer: Mar-Sep)
Same in S. Hemis., but reversed
At poles summer solstice (June 21 in North) = 24 hrs. day
Poles Winter Solstice (21 Dec) = 24 hr. Night
Earth is tilted on its axis 23.5˚
As Earth rotates around sun (365 days)
One pole or other is closer to sun:
Seasons
Tilt toward sun at Summer Solstice (June 21-North)
At poles = 24 hrs. day
Tilt away from sun at Winter Solstice (21 Dec – N.)
At Poles = 24 hr. Night
Equator has little seasonal variation in temp.
Coriolis Effect
Eastward rotation of Earth on its axis 15°/hr
Deflects moving objects (air, water) away from initial course
Earth spins faster at Equator (0°): 1700 km/hr
Than at higher latitudes: 1260 km/h at 43°
WORLD BIOMES
ARCTIC
Encircles polar seas
Similar to Antarctic (arctic larger)
Portion is permanent ice
Very cold Winter (record -96˚F/-71˚C – Siberia)
Very dry (1-8”, 3-20 cm/year)
Day Length: 22 hr dark (winter), 22 hr light (summer)
Polar Bear, Orca, Walrus, Beluga Whale, N. Fur Seal, Sea lion
TUNDRA
Tundra: “Treeless Plain”
South of Arctic circle
Alaska, Canada, Russia, Norway, Sweden, Finland, Greenland
Permafrost: Permanently frozen sub-soil
Consequences: physical barrier to roots
Low temps slow down decomposition, promotes peat buildup
Retards water percolation = boggy soil
Very slow plant growth
Taiga (Boreal Forest)
Coniferous forests (evergreens)
Pine, spruce, fir + moss, lichens
Largest Biome (Canada, N. Europe, Asia)
Warm, rainy summer (Avg. =70F, 12-33” rain/yr.)
COLD winter (Avg. 30F, low as – 65F)
Bears, Moose, Wolves, Canadian Lynx
Temperate Deciduous Forests
Trees drop leaves in Winter (Deciduous)
Many plants go dormant
4 Distinct seasons
Mod. Temp (Avg. =50F), winter freeze
Mod. Rain (30-60”/75-150 cm)
Maple, Birch, White Oak, Elm
Shrubs, ferns, moss, lichen = lower canopy
Sm. herbivorous mammals, amphibians & reptiles
Cool Temperate Forests (Maritime)
Temperate Coniferous Rain Forests
Frequently listed with Taiga
Pacific NW USA, SW Canada (Vancouver, Victoria)
Mild Temps. year round (Ocean influences)
High Rainfall (60-150” per year)
Redwood, Spruce, Cedar, Douglas Fir
Grasslands
Eurasian Steppe, Prairie (N. America), Pampas (S. America)
Fire limits trees, grasses re-sprout
Largely altered for cultivation
Tall grass(wet), short grass (dry), flowering plants
Large Herbivores: Bison, Antelope
Prairie Dogs, rabbits, mice = Hawks, Falcons Badgers, Foxes, Coyote
Savanna
Grasslands w/ trees & shrubs
Dry Tropical Forests/Tropical Grasslands
Warm all year (68-86°F)
2 Seasons: Rainy (Summer), Dry (Winter)
4” (Dry Season), 15-25” (Wet Season)
Africa: Acacia, Elephant, Lion, Hyena, Zebra, Giraffe
Australia: Eucalyptus, Kangaroos, Koalas, Emus
S. America: Capybara, Marsh Deer
Tropical Rain Forest
Tropical Rain Forest
Warm all yr. (68-88%)
Rainy (75-260”/yr. = 190-660 cm/yr)
50% of all animals on Earth
Produces 40% of Oxygen
25% of all medicine (1,400 potential Cancer drugs)
4 Vegetation layers:
Emergent Trees, Upper Canopy, Understory, Forest Floor
Most animals live in Upper Canopy
Tropical Rain Forest
Few Soil Nutrients
Rain washes away
Rapid Decay from heat & humidity
Many Decomposers:
Fungi, Ants, Termites
Low light in understory
Plants adaptations: shallow roots; epiphytes; vines; large, dark leaves
Tropical Rain Forest Issues
Only cover 6% of Earth surface
Slash & Burn for Agriculture:
Removes most nutrients
99% nutrients held in tree roots
Few years before soil is depleted of all nutrients
Farms must be abandoned
Decades/centuries to re-grow
Desert
Evaporation > Precipitation (≤ 10 in.)
Temperate: Furthest N. & Coldest
Great Basin (NV,UT,ID); Gobi (Cent. Asia)
Subtropical: 15-30° N & S, Warmer
S.W. USA / N. Mexico (Sonora), N Africa (Sahara), Australia, Chile / Peru
Little Cloud Cover = Hot, dry days & Cold nights
Soils: Few organics, clay, hardpan, sand
Desert Adaptations
Plants:
Tap or shallow roots
Succulents
Small leaves
Light-colored leaves
No Leaves (Thorns)
Waxy cuticle
Dormant in extreme seasons
Animals:
Moisture from food
Nocturnal
Burrows
Small size = decreases surface area
Shrublands
5 Places on Earth (30-40 degrees N & S of Equator)
(1) S. Calif., (2) Chile, (3) SW Australia, (4)S. Africa, (5)SW Europe—NW. Africa
West side of continents, cold ocean currents
Winter Rain, Summer Dry (High Evaporation, windy)
Plants of 5 regions have similar adaptations & appearance = Convergence
Shrublands Plant types:
Shrubs
drought tolerant trees
Spring annuals & grasses
Plant adaptations (similar to deserts):
Small, waxy, or succulent leaves
Many have pale colored leaves
Compact size
Fire
South African Fynbos, Mediterranean (Europe, N. Africa)
Coastal Sage Scrub, Chaparral (S. California)
Chaparral characteristics:
South facing slopes
Dark leaves
Tough leaves
Waxy leaves
Fire adapted
Coastal Sage Scrub Characteristics:
North facing slopes
Light colored leaves (gray)
Soft leaves
Oily leaves
Prickly pear cactus
Fire adapted
Fire Adapted Ecosystems
10-40+ year fire cycle
Need for fire:
Seed germination
Remove litter (slow decomposition)
Adds organic nutrients to soil
Plant adaptations:
Oils promote fire
bark protection
new shoots from base roots or crowns (Root-crown sprouting)
Seed coats
stimulate some plants to increase and/or flower
Oak Woodlands
Associated with Chaparral & Coastal Sage Scrub
Foothills, valleys, riparian areas
Deeper soil, more moisture, less wind
Other woodland species:
Poison Oak, bunch grass
Near creeks (riparian): Western Sycamore, White Alder, California Walnut, Fremont’s
Cottonwood
Oak Woodlands
Southern Californian Urban Sprawl: 90% of coastal sage scrub has been lost to
development (only 10% left)
Aquatic Biomes
Aquatic ecosystems are linked
Lakes flow to rivers then estuaries then oceans
Rivers bring nutrients/minerals from land to sea
Seawater & freshwater evaporates & eventually falls as rain over all aquatic zones
Salt is left behind
Aquatic Biomes - Freshwater
Lakes & Ponds
Inland depressions of standing water
Arise from:
Glacial abrasion
volcano craters
silt deposition in stream beds
Earth’s shifting crust
Dams = artificial lakes by damming rivers for power, irrigation, water storage
Lakes & Ponds Two types:
Oligotrophic (nutrient –poor)
Eutrophic (nutrient- rich)
Agricultural & urban run-off = algae blooms, low dissolved O2, fish kills
Eutrophication
Stratified in summer & winter:
Warm layer at top in summer
Cold layer & ice at top in winter (prevents freezing of whole lake)
Rivers & Streams
Continuously moving water
Begin as:
Outlets of lakes/ponds
Seep from shallow groundwater
Snowmelt (mountains)
2 Types:
Perennial (wet year round)
Intermittent (seasonally dry)
Typical of arid zones
Rivers & Streams Change direction during high velocity events
Humans extensively develop floodplains
Most modified by Dams or channelized with concrete
Damming the Yangtze River (China)
Hydroelectric power for industrial development
Protect millions from floods
BUT:
Relocation of 1.9 million people
Destruction of River ecosystem
Extinction of Chinese River Dolphin
Submerge ancient archeological treasures (2,000-7,000 yrs.)
Siltation = poor water quality, dam may fail in 50 years
Aquatic Biomes - Marine
Oceans
4 main bodies:
Pacific, Atlantic, Indian, Arctic
Oceans
Divided into zones:
Pelagic (Open ocean)
Benthic (in or on soil)
Littoral (Shoreline)
Pelagic: Open Ocean
Organisms swim or float
Phytoplankton = most of Earth’s oxygen (upwelling)
Food web:
Phytoplankton zooplankton  Anchovy mackerel  dolphin
Dark below ~120 m
Many bioluminescent animals
Benthic: Ocean bottom
Organisms live in or on soil:
Detritivores: feed on marine snow (dead organisms from above)
Continental shelf/slope:
Kelp, seastars, flat fish brittlestars, tube worms
Benthic Abyssal zone: deep sea plain
Brittle stars, sea cucumbers
Deep sea trenches & Hydrothermal vents:
Hot wate
Chemical reaction sulfate + H2O = H2S
Chemosynthesis: Bacteria convert H2S into energy
Need no light
These bacteria live in Tube Worm tissues
Littoral (Intertidal): Shoreline (Rocky or Sandy)
Rocky Shore
Stressful habitat
Wave stress, alternate dry & wet periods, sun (UV) exposure, rocks
Zonation:
Upper intertidal: closest to land, mostly dry. Periwinkle snails, Barnacles
Mid-intertidal: Dry ½ of time, wet ½ time. Algae, limpets, crabs, mussels, purple sea
urchin, Sea anemones
Lower intertidal: furthest from shore, mostly submerged. Algae, sea stars, red sea urchin,
sea hare, sea cucumber
Sandy Shores
Difficult place to live
Abrasive sand
Tides = wave stress, wet/dry fluctuation
Animals live on sand (epifauna) or in sand (infauna)
Sand crabs (ampipods), worms (nematodes) burrow in sand & eat detritus
Clams (bivalves) breathe thru siphon
Shorebirds feed & nest
Marine Biomes - Estuaries
Swamps:
Wetland with trees
Present in Salt & Freshwater ecosystems
Mangroves (Tropical)
Everglades - Florida (Tropical/subtropical)
Salt Marshes:
Protected coastlines (mid-high latitudes)
No Trees
Grasses, succulents, small shrubs
Halophyte plants (“salt loving”)
Adaptations: exude salt from tips, shunt salt to old leaves & drop old leaves
Pacific Flyway: birds migrate between Northern breeding grounds (summer) & southern
winter/feeding grounds
Estuary & Wetland Issues
Unappreciated
Most have been filled in:
Development, harbors, power plants, agriculture, roads
California has greatest wetland losses
90% total wetlands, 75% salt marsh
Restoration:
Return wetland to “natural state”, former function
Everglade Restoration: Largest restoration effort on Earth
Interagency effort: Federal & State, Universities, environmental groups