Topic 4 Flashcards
Macroclimate
Large scale climate patterns
Ex: biomes
microclimates
Small scale climate patterns
Ex: mountain —> changes in temp at diff elevations
Albedo
reflectivity of landscape.
- vegetation and ground cover.
Ex: white snow can reflect up to 80% of visible light, dark soil generally reflects less than 10% of visible light. The same amount of solar energy heats up dark soil more than white snow.
Microclimates: Vegetation & Ground Cover
• Trees, shrubs & plant litter can produce important microclimates.
Ex:
- soil surface in full Sun heats to high temps (48°C in bare soil away from shrubs.
- shading of soil surface by low shrubs lowers max temp (29°C in litter under low shrub)
- a layer of leaf litter lowers max temp even more (27°C in soil under low shrub)
- greater leaf area and numerous twigs of tall shrubs intercept more light, creating the coolest temperatures (21°C in litter under tall shrubs. 23°C in soil under tall shrub)
Temperature & organism performance
Performance: this can measures of survival, growth, or reproduction.
Range of tolerance: conditions where organisms can survive
Optimum conditions for reproduction: optimum conditions for reproduction will often be a narrow subset of the conditions in which a species can survive.
Mortality, survival but no growth, growth but no repro, repro
Temperatures & Photosynthesis
Optimum range for photo
• higher for desert species than boreal species
Range of tolerance
• desert species can tolerant higher temps than boreal forest
A moss from a boreal forest photosynthesizes at a maximum rate at 25°C.
A desert shrub photosynthesizes at a max rate at 44°C.
— op conditions for photo is amount 45°C
Temperature and microbial activity
Psychorphilic bacteria (cold-loving)
- rate of pop growth by these Antarctic bacteria was highest at approximately 4°C.
- each point represents pop size after 80 hours of incubation at a particular temp.
Thermophilic bacteria (heat-loving)
- rate if sulfur oxidation by these microbes from a 59°C hot spring was highest at approximately 63°C.
Temp and animal performance
Metabolize energy intake (MEI) in eastern fence lizards is temp dependent.
MEI = c - f - u
Energy intake = E consumed - e lost in feces - e lost in urine
South Carolina S. undulatus
New jersey S. undulatus
For both pops of lizards, metabolizable energy intake (MEI) was greatest at 33°C.
Surviving extreme temperatures: resistance
Insulation
- fur, feathers, blubber
Hibernation - prolonged periods of reduced metabolic activity (ex:slow heart rate, lower body temp)
Ex: wood frog —> cryoprotectants
Ex: bears (black and grizzly) —> slow metabolism
Torpor - similar to hibernation but on a shorter time frame
- ex: humming birds
Avoidance
- tunnels make microclimates —> help control body temp
Cryoprotectants: compounds in cells that prevent cells from busting —> allows to control when ice grows, resist by allowing body to freeze and defrost in spring
Surviving extreme temperatures: migration
Monarch butterflies
In migration there can be many gens for 1 way and other way only 1 gen.
Balancing heat gain against heat loss (energy budget)
What drives amount of heat in an organism.
HS = Hm ±Hcd ±Hcv ±Hr -He
Hs = total heat stored in an organism
Hm = Heat gain via metabolism heat gain. Energy released during cellular respiration
Hcd = Heat gain/loss via conduction heat gain or loss. Heat exchange between objects in physical contant
Hcv = Heat gain/loss via convection heat gain or loss. Heat exchange between a solid body and moving liquid or gas. Ex: wind
Hr = Heat gain/loss via radiation heat gain or loss. Heat exchange through electromagnetic radiation ex: solar, radiation from the sun or out going heatfrom body
He = Heat loss via evaporation heat loss. Heat lost through evaporation of H2O on skin of organism. Moisture on skin evaporates and cause the skin
Hcd and Hcv heat flow always from warmer to cooler
Heat Exchange Pathways: flower
Heat gain by radiation (Hr) from the sun
Heat loss or gain by convection (Hcv) from wind
Heat loss or gain by conduction (Hcd) at roots
Heat loss by radiation (Hr)
Heat loss by evaporation of water (He)
Heat game from metabolism (Hm)
Heat Exchange Pathways: Arctic Plants
Cold environment, dry, short days/summers/growing seasons.
Grow close to ground, if any heat from ground caused by solar radiation, also increase surface area to get more solar radiation.
Max heat game
Min heat loss
Darkly, pigmented leafs, reduce reflection and increase heat gain by radiation (Hr)
Compact, hemispherical growth, hormone decreases exposure of plant surfaces to wind. = Low convection, heat loss to wind.
Arctic and Alpine plants also increase HR by orientating their leaves perpendicular (towards) to sunlight
Ground-hugging growth form increases. Heat gain from solar- heated surroundings through radiation Hr and conduction Hcd.
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Sunlight reflected inward by parabolic shaped dryas flowers, heats interior of flowers.
Sun tracking dryas flowers, keeps flowers, facing the sun for several hours each day.
Flower temperature = 25°C
Air temperature = 15°C
Basking insect temperature = 25°C
Heat Exchange Pathways: Desert Plants
Hot environment
Min heat gain
Max heat loss
Highly reflective leaves reduce heat game by radiation (Hr)
High convective heat loss to wind (Hcv)
Low conductor of heat game from ground (Hcd)
Desert plants also reduce Hr buy orientating their leaves parallel (away) to sunlight
Open growth form and small leaves increase exposure of plant surfaces to wind
Evaporative cooling (He)
- Panting
Ex: dogs - sweating
Ex: horses, humans
-Salivation
Ex: kangaroo —> blood vessels on arms, lick —> evaporation —> cools
Kangaroos
—> move to shade to reduce Hr
—> increase Hcd (heat loss) buy digging and laying in cool dirt
Body Temperature Regulations —> Animals:
Body Temperature maintenance: 2 types
• poikilotherms - body temperature varies with environment 
Ex: snake
• homotherms - maintain relatively constant internal body temp
Ex: bobcat
Poikilotherms <—> Ectotherms
Homotherms <—> Endotherms
Body Temperature Regulations —> Animals:
Metabolic Rate: 2 types
• endotherms - high metabolic rate, conserve heat, use insulation
Ex: birds and mammals
• ectotherms - low metabolic rate, use external sources of heat, use behaviour to maintain temperature Ex: basking
Ex: fish reptiles, amphibians, invertebrates, plants
Poikilotherms <—> Ectotherms
Homotherms <—> Endotherms
Temperature Regulation by Ectothermic Animals
Eastern fence lizard:
- modify body to control temperature —> to get close to ideal.
- New Jersey, and South Carolina.
- The field and preferred temperatures of lizards from both populations, closely match the temperature at which Metabolizable energy intake is maximum.
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Respond to environment raised in, morphological adaptations
• Grasshopper reared at low temperatures develop dark pigmentation that is highly absorbent of visible light.
• grasshoppers reared at high temperatures, develop reflective light pigmentation.
Temperature Regulation by Thermogenic Plants
Almost all plants are poikilothermic ectotherms.(temperature changes with environment and have low metabolic rate.)
Exception: family Araceae use metabolic energy to heat flowers.
Starch is translocated from the tap root to the spadix
High metabolic rate of spadix generate sufficient heat to melt snow. (Hm Increase)
Snow is melted by radiation and conduction (Hr and Hcd decrease)
Water Regulation on Land:
Animals
Wi=Wd +Wf +Wa -We –Ws
Wi = internal water of animal
Wd = water taken by drinking (gain)
Wf = water in food eaten (gain)
Wa = water absorbed from air (gain)
We = water lost to evaporation (loss)
Ws = water lost to secretion & excretion (loss)
Extent to which Wd and Wf is important depends on the type of enviro live in.
Main avenues of water acquisition by most terrestrial animals is with food and drinking.
Main avenues of water loss by most terrestrial animals is evaporation
Water acquisition: kangaroo rats and desert beetle
Kangaroo rats:
- can go without drinking (no Wd) and obtain all the water it needs from its food (Wf).
- most water loss is through evaporation (We).
- secretions (Ws) result in moderate water losses
- desert organism
Namib, desert beetle:
- fog-laden winds blow across dune crests.
—> moisture in fog condenses on abdomen
—> beetles gather on dune crests, face into the fog-laden wind, and tip their abdomens upwards
—> grooves in the abdomen collect condensed water and direct it towards the head
—> beetles drink from the water droplet that collects around their mouths
—> water fall down grooves on body and the
- need Wd —> challenging b/c desert
Swift:
- small legs, b/c aerial predator, don’t need to be on land, sleep on wings, only on ground for breeding
—> skim across H2O to drink while flying
Water Regulation on Land: Plants
Wi=Wr +Wa -Wt -Ws
Wi = internal water of plant
Wr = water absorbed by roots (gain)
Wa = water absorbed from air (gain)
Wt = water lost by transpiration (loss)
Ws = water lost through secretions (loss)
Plants lose water mainly through transpiration (this involves the evaporation and diffusion of water) Wt
Plants lose fluids with secretions such as nectar in flowers or extrafloral nectaries. Ws
In some environments plants absorb water from moist air.
Wind increases evaporative water loss
The main avenue of water acquisition by plants is from the soil solution through their roots.
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On dry sites, the plant grows a dense network of deeply penetrating roots. Invest more energy on roots. Try to increase Wr.
On moist sites, the plant grows a sparse network of shallow roots. Try to increase Wa
Water Conservation by Plants
Adaptations
- root development (increase Wr)
- reduced leaf area compared to roots (decrease Wt)
- periodic dormancy (decrease Wt)
- waxy cuticle (decrease Wt)
- thick leaves with few stomata (decrease Wt)
- stomata open at night (decrease Wt), stomata allow release of Gas.
Energy Sources: Heterotrophs
Use organic molecules
Need other organisms
Heterotropic-
Use organic molecules as a source of carbon and for energy
—> heterotroph
Energy Sources: Autotrophs
Get energy and C from the environment
Don’t depend on other organisms to live
Photosynthetic - use CO2 for Carbon, sunlight for energy
—> autotroph
Chemosynthetic
—> autotrophs
Energy Sources: Chemosynthetic
Use inorganic molecules for carbon and a source of energy
—> autotroph
Detritivores
Type of heterotroph
Feed on nonliving organic(‘dead”) matter
Important roles in ecosystem
—> soil respiration
—> break down materials
Limitions
—> food tends to be rich in C, poor in N
Herbivores
- heterotroph
- eats plant material —> often need to consume large amounts
- low in N in diet
- plants have a lot of chemical defences
—> toxins
—> digestion reducing compounds (Tamins) - plants have physical decencies
—> thorns
—> cellulose and lignin - some organism slow down speed or speed up digestion or have larger stomachs
Carnivores
- heterotroph
- eats meat
- food more rich in N, face less of nutrients l limitations
- have to eat prey that are difficult to catch and may even harm the predator
Mixotrophy
Gain energy from photosynthesis and organic materials
Ex: bacteria, photosynthesis’s and can consume microorganisms
Ex: carnivorous plants
Omnivory
Consumes plant and animal materials
Ex: chimpanzees that eats fruit and hunts for meat
Ex: coyotes, mainly eat meat but can eat fruit
Ex: humans
Photosynthesis
2 steps involved
Light rxns:
- plant uses light as source of energy
—> transfer energy to electrons
—> used to synthesize energy that’s useable by the plant
Ex: ATP, NADP
Calvin cycle:
- ATP and NADPH act energy donors
—> synthesize sugar
—> can happen when light unavailable but doesn’t need to
Energy sources table
Prokaryotic (bacteria, Archaea):
- heterotrophic
- photosynthetic
- chemosynthetic
— draw on a greater variety of energy sources than the eukaryotes
Protist:
- heterotrophic
- photosynthetic
— include many heterotrophic species
Plants:
- heterotrophic
- photosynthetic
— mainly photosynthetic, with a few heterotrophic species
Animals and fungi
- heterotrophic
— all fungi and animals are heterotrophic
Photosynthetic Pathways
• C3 Photosynthesis
• CO2 + RuBP + enzyme (RUBISCO) èphosphoglyceric acid (PGA; 3 carbon acid)
• Plants must open stomata to let in CO2
— b/c not a problem if lose H2O when H2O very available around
• Also allow water to escape
• Water flows out faster than CO2 flows in
• Concentration gradients + RUBISCO’s low affinity for CO2
• More common in moist, cooler climates
Photosynthetic Pathways
• C4 Photosynthesis
Don’t want to lose H2O, in dryer areas
Light rxn and Calvin cycle occur in diff cells —> reduce amount of stomata needed to open
• Fixation of C & light-dependent reactions occur in different cells (mesophyll & bundle sheath, respectively)
- less H2O less
- 3% of plants use this process, main species that use this grasses and crops
• Reduces water loss by reducing need for open stomata
• Fixes CO2 using enzyme with high CO2 affinity
• Fewer stomata need to open to take in CO2
• Disadvantage: requires more energy
Photosynthetic Pathways
• CAM Photosynthesis (Crassulacean Acid Metabolism)
• Succulent plants; arid environments.
- very dry environment
• Light-dependent reactions & C fixation separated in
time but in same cells.
- stomata not open during day to reduce H2O loss (reduce how often stomata open)
- Calvin cycle part at night when cooler
- can store products until daytime
- photosynthesis during day
Disadvantage: low rate of photosynthesis but comes with price of efficient H2O retention.
