Topic 4

Question 1

Macroclimate

Answer 1

Large scale climate patterns

Ex: biomes

Question 2

microclimates

Answer 2

Small scale climate patterns

Ex: mountain —> changes in temp at diff elevations

Question 3

Albedo

Answer 3

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.

Question 4

Microclimates: Vegetation & Ground Cover

Answer 4

• 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)

Question 5

Temperature & organism performance

Answer 5

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

Question 6

Temperatures & Photosynthesis

Answer 6

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

Question 7

Temperature and microbial activity

Answer 7

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.

Question 8

Temp and animal performance

Answer 8

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.

Question 9

Surviving extreme temperatures: resistance

Answer 9

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}

Question 10

Surviving extreme temperatures: migration

Answer 10

Monarch butterflies

In migration there can be many gens for 1 way and other way only 1 gen.

Question 11

Balancing heat gain against heat loss (energy budget)

Answer 11

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

Question 12

Heat Exchange Pathways: flower

Answer 12

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)

Question 13

Heat Exchange Pathways: Arctic Plants

Answer 13

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.
———————————————————
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

Question 14

Heat Exchange Pathways: Desert Plants

Answer 14

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

Question 15

Evaporative cooling (He)

Answer 15

• 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

Question 16

Body Temperature Regulations —> Animals:

Body Temperature maintenance: 2 types

Answer 16

• poikilotherms - body temperature varies with environment 
Ex: snake

• homotherms - maintain relatively constant internal body temp
Ex: bobcat

Poikilotherms <—> Ectotherms
Homotherms <—> Endotherms

Question 17

Body Temperature Regulations —> Animals:

Metabolic Rate: 2 types

Answer 17

• 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

Question 18

Temperature Regulation by Ectothermic Animals

Answer 18

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.
———————————————————
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.

Question 19

Temperature Regulation by Thermogenic Plants

Answer 19

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)

Question 20

Water Regulation on Land:

Animals

Answer 20

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

Question 21

Water acquisition: kangaroo rats and desert beetle

Answer 21

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

Question 22

Water Regulation on Land: Plants

Answer 22

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.

————————
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

Question 23

Water Conservation by Plants

Answer 23

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.

Question 24

Energy Sources: Heterotrophs

Answer 24

Use organic molecules

Need other organisms

Heterotropic-
Use organic molecules as a source of carbon and for energy
—> heterotroph

Question 25

Energy Sources: Autotrophs

Answer 25

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

Question 26

Energy Sources: Chemosynthetic

Answer 26

Use inorganic molecules for carbon and a source of energy
—> autotroph

Question 27

Detritivores

Answer 27

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

Question 28

Herbivores

Answer 28

• 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

Question 29

Carnivores

Answer 29

• 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

Question 30

Mixotrophy

Answer 30

Gain energy from photosynthesis and organic materials

Ex: bacteria, photosynthesis’s and can consume microorganisms
Ex: carnivorous plants

Question 31

Omnivory

Answer 31

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

Question 32

Photosynthesis

Answer 32

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

Question 33

Energy sources table

Answer 33

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

Question 34

Photosynthetic Pathways

• C3 Photosynthesis

Answer 34

• 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

Question 35

Photosynthetic Pathways

• C4 Photosynthesis

Answer 35

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

Question 36

Photosynthetic Pathways

• CAM Photosynthesis (Crassulacean Acid Metabolism)

Answer 36

• 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.