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Characteristics of the Tropical Rainforest
- Within 10° of equator
- Stable temperature across months
- 2000-4000mm rain evenly distributed across months (leaches soil nutrients, Micorrhizae help to maintain)
- Tall trees add a third dimension to this biome
- Important staple foods (plants and animals) and medicines which are increasingly exploited
Characteristics of Tropical Dry Forest
- Between 10°-25°
- More seasonal than Tropical Rainforest
- Soils richer, but vulnerable to erosion.
- Shares many animal and plant species with tropical rainforests.
- Heavily settled by humans; extensive slash/burn.
Characteristics of Tropical Savannah
- North and south of tropical dry forests within 10°-20°
- Wet and dry seasons.
- Drought can lead to lightning-caused wildfires.
- Soils - low water permeability.
- Saturated soils keeps trees out.
- Landscape - more two-dimensional w/ increasing pressure to produce livestock
Characteristics of the Desert
- 30° from equator
- ~20% of earth’s land surface.
- Water loss > precipitation.
- Soil low in organic matter.
- Plant cover sparse / absent.
- Animal abundance low, but biodiversity may
- be high. (strong behavioral adaptations, endemics)
- Human intrusion increasing
Characteristics of Mediterranean Woodland and Shrubland
- All continents except Antarctica.
- Climate cool & moist fall, winter, spring; hot & dry in summer (fires).
- Fragile soils, moderate fertility.
- Evergreen trees and shrubs.
- Fire-resistant plants (due to fire regime).
- Long history of human intrusion.
- Cleared for agriculture.
Characteristics of Temperature Grasslands
- Extremely widespread distribution.
- Annual rainfall 300 - 1,000 mm.
- Periodic droughts.
- Soils nutrient rich & deep.
- Dominated by herbaceous (non-woody) vegetation.
- Large roaming ungulates. (Bison vs. cattle)
Characteristics of Temperate Forests (Old Growth)
- Between 40°-50°
- Rainfall 650 - 3,000 mm.
- Fertile soils
- Long growing seasons dominated by deciduous (not evergreen) plants.
- Short growing seasons dominated by conifers.
- Biomass production can be very high
- Many major human population centers
Characteristics of Boreal Forests (Taiga)
- Northern Hemisphere (11% of earth's land area)
- Thin, acidic soils low in fertility.
- Dominated by evergreen conifers.
- Relatively high animal density.
- Historically, low levels of human intrusion
Characteristics of Tundra
- Covers most land north of Arctic Circle (60°-90º).
- Cool & dry with short summers.
- 200 - 600 mm precipitation.
- Low decomposition rates (“permafrost”)
- Supports substantial numbers of native mammals.
- Human intrusion historically low, but increasing as resources become scarce.
Characteristics of Mountains
- Mountains in the Sky
- Built by geological processes and thus concentrated in belts of geological
- Climate changes with elevation and latitude.
- Soils are well-drained and thin.
- Flora and fauna change with elevation.
- Historically used as a source of raw materials for human settlements.
Characteristics of deep blue sea
- Oceans most extensive biome on earth
- Pacific basin > Atlantic basin > Indian basin
- Average depth ~3900-4000m
- Littoral zone: shallow shoreline
- Neritic zone: coast to margin of continental shelf
- Epipelagic zone < mesopelagic zone < bathypelagic zone < abyssal zone < hadal zone
- Benthic: habitat ON BOTTOM
- Pelagic: habitat NOT on bottom (regardless of depth)
- ~80% of solar energy is absorbed in first 10m of ocean (photic zone)
- Very little solar energy past 600m (aphotic zone) with bioluminescence as sole source of light
- Thermocline: Layer of water through which temperature changes rapidly with depth.
- Very low oxygen content in sea water
- Oceans contribute 25% of total photosynthesis in the biosphere (limited to upper zone)
- Chemosynthesis near underseas hotsprings
Characteristics of Shallow marine waters
- Reefs and kelp beds both grow in surface waters with sufficient light for photosynthesis (limited by temperature)
- Currents deliver oxygen and remove wastes
- Reefs/kelp beds among most productive and diverse ecosystems
- intertidal zone: rocky and sandy shore
- Organisms exhibit amphibious characteristics
Characteristics of Rivers and Streams
- Vertically divided: water surface, water column, benthic (bottom)
- Nutrients from land erosion and suspended bottom sediments
- Temperature closely tracks air temperature
- Oxygen content is inversely correlated with temperature
- River continuum concept: small headwater stream (cool, oxygenated water), medium headwater stream (moderate temp, lower oxygen), and large rivers (highest temp, lowest oxygen).
Characteristics of Lakes
- Most freshwater in just a few lakes
- Littoral zone: shallows
- Limnetic zone: open waters (epiliminion [warm surface], metalimnion [temp changes with depth], hypolimnion [cold and dark]
- Lake color dependent on light absorption and biological activity
- Seasonal temperature changes (freezing at top, mixing)
- Local conditions mask the tides
- Oligotrophic: low biological production, may be well oxygenated (blue and lovely)
- Eutrophic: high biological production, possibly oxygen deficient (green)
- Humans have led to eutrophication and exotic invasive species
What is the equation for photosynthesis?
6CO2 + 12H2O -> 6O2 + C6H12O6 + 6H2O
Various body temperature regulation
- Poikilotherms: body temperature varies directly with environmental temperature
- Homeotherms: body temperature remains constant, regardless of environmental temperature
- Ectotherms: use an external energy source
- Endotherm: rely on internal metabolic energy
Temperature and microbial activity
- Psychrophyllic: extreme cold loving (marine, around antarctica)
- Thermophillic: hot temperatures (hot springs)
Total heat storage equation
- Hs = Hm ± Hcd ± Hcv ± Hr - He
- Hm: heat gained via metabolism
- Hcd: heat gained/lost via conduction (2 solids)
- Hcv: heat gained/lost via convection (solid/liquid)
- Hr: heat gained/lost via radiation
- He: heat lost via evaporation
Temperature regulation of thermogenic plants
- Eastern skunk cabbage uses metabolic energy to heat flowers (attracts pollinators, prevents freezing)
- Starch storage in in root is translocated to flower and metabolized at high rates
Temperature regulation of Plants (arctic and tropic alpines)
- Arctic: increase radiative heating and decrease convective cooling (growing close to ground, increase SA/V ratio, darker color)
- Tropic Alpine plants: drastic temperature difference between night and day
- Retain dead leaves for insulation, thick pubescence
Temperature regulation of lizards/grasshoppers
- Lizards: use environment (burrows, dark pigment, sun basking, press body to ground) to maintain optimal temperature
- Grasshoppers: become pigmented during cold times, and lose pigment during hot times
- Elevated internal temperature to prevent fungal growth
Temperature regulation of Aquatic endotherms (penguin, seal whale)
- Water is a heat sink (fairly even)
- Many are air breathers and insulated (fur or fat)
- Countercurrent heat exchange: cool arterial blood from gills flows to swim muscle, warms in muscle, and leaves warmed
- Swimming muscles allow large fish to keep temperature elevated from surroundings
Temperature regulaton of moths/bees
- Insects use flight activity to regulate/maintain body temperature.
- Bees maintain temperatures regardless of air temperatures
- Moths thorax has a maximum temperature, but the flow of blood acts as coolant moving hot blood from thorax to abdomen
Temperature regulation for extreme temperatures
- Inactivity (seek shelter during extreme periods)
- Reduce metabolic rate
- Hummingbirds: enter state of torpor (decreased metabolic activity)
- Bears: hibernation (winter/cold)
- Lizards/frogs: estivation (summer/dry)
- Arctic species tend to have a larger range of temperatures they can easily adapt to than tropical species
- Relative humidity = water vapor density / saturation water vapor density x 100
- Vapor pressure defecit: different between actual water vapor pressure and saturation water vapor pressure
- Measure of the potential of air to take up moisture (high VPD = steeper gradient, low VPD = air near saturation)
- High VPD increases evaporative loss from organism
What happens to organisms in different osmolarities?
- Isosmotic: salts/water diffuse evenly (marine invertebrate)
- Hyperosmotic: salts diffuse out, osmosis in (freshwater fish)
- Hyposmotic: salt diffuse in, osmosis out (marine fish)
Information about Water potential
- Ability to move/do work
- Flows from higher Ψ to lower Ψ
- Solute potential (alters the flow/rate of osmosis)
- Pressure potential (+/- pressure must be taken into account)
- Pure water Ψ = 0
- Ψplant = Ψsolute + Ψmatric + Ψpressure
Describe water regulation on land (w/ equation)
- Two major challenges: evaporative loss to environment and reduced access to replacement water
- Internal water equation for animals:
- Wia = Wd + Wf + Wa - We - Ws
- Wd: drinking
- Wf: food
- Wa: absorption
- We: evaporation
- Ws: secretions
- Wip = Wr + Wa - Wt - Ws
- Wr: roots
- Wa: absorption
- Wt: transiration
- Ws: secretions