TemperatureRelations (Ch. 5)

Endothermic Animals

Endothermic Animals• HS = Hm + Hcd + Hcv + Hr - He

• Use behavior + metabolism (Hm) too

Endothermic Animals• Thermal neutral zone: range temperature

where metabolic rate stable– Varies by species

Humans?

Endothermic Animals• Humans tropical: all over planet!

Aquatic Endothermic Animals• Cold water problem

– Convective heat loss: 20x faster than air (still water) to 100x faster (moving water)

• Solutions? (3)

“Stop the lecture,you’re killing me!”

Aquatic Endothermic Animals• Solutions:• 1) breathe air (avoid gill surface exposure)• 2) insulate! Blubber (whales), waterproof feathers

(penguins), air-trapping fur (sea otters)

“Stop the lecture,you’re killing me!”Otter fur: up to 1 million /sq. in.

Aquatic Endothermic Animals• Solutions:• 3) limit heat loss

from appendages by countercurrent heat exchangers

Exceptional fishes• Some fishes regulate temp.

swimming muscles• Ex, bluefin tuna (fast!)

Exceptional fishes• Countercurrent heat exchange keeps muscle

temp. constant– Artery blood cooler in this case…

Surviving Extreme Temperatures• Reducing Metabolic Rate

– Hummingbirds: enter torpor (reduce metabolic rate & lower body temp.)

Months?

Surviving Extreme Temperatures• Reducing Metabolic Rate (for months)

– Hibernation - Winter (temperate climates)– Ex, black bear

Avoid summer?

Surviving Extreme Temperatures• Reducing Metabolic Rate

(for months)– Estivation - Summer (deserts)– Ex, lungfishes– Bury in mud to survive dry

season

WaterRelations (Ch. 6)

Why Water Matters• Life aquatic (you: 60% water!)

• Solute concentration affects enzymes

• Water useful: temp. regulation– HS = Hm + Hcd + Hcv + Hr - He

Water Content Air• Terrestrial: Most water loss

evaporation (concentration gradient)– How express air water content?

Water Content Air• Relative Humidity:

Water Vapor Density

Saturation Water Vapor Density (x 100%)

– Water vapor density = gm water vapor per unit volume (meter cubed)

– Saturation water vapor density = water vapor air potentially holds

• Changes with temperature…..(how?)

Water Content Air

• Note kPa: pressure unit (kiloPascals)

• Pascal: metric unit pressure (1 Newton per sq. meter)

Vapor pressure….

Water Content Air• Water Vapor Pressure (WVP):

Partial pressure water vapor.• Saturation Water Vapor Pressure

(SWVP): Pressure water vapor at saturation

• Vapor Pressure Deficit (VPD): SWVP – WVP: drying power air

Water Movement: Soil to Plant• Water: flows down water potential gradient

Water potential?

Water Movement: Soil to Plant

• Water: flows down water potential gradient.

• Water potential (Psi): capacity water to perform work (water’s free energy content)

• “Tendency water to move from one place to another”– Pure Water Psi = 0 MegaPascals (MPa)

PsiMega = one million (106)

• Units: megaPascals (MPa)

• Psi values negative! Why?

Mega = one million (106)

• Psi values negative! Why?• Water potential lowered by:

– Dissolved substances (solute potential)– Attraction water to charged surfaces (matric

potential)– Pull of evaporation (tension) on water in plants

(negative pressure potential)

• Water potential raised by:– Pressure (positive pressure potential)

Water Movement: Soil to Plant

• Psiplant = Psisolute + Psimatric + Psipressure

• Psisoil = Psisolute + Psimatric• Solute potential: salts. Psisolute important

saline soils • Matric potential (#1 all soils): attraction

water to clays (tiny mineral materials) in soil

Water Movement: Soil to Plant

• Concept! If Psiplant < Psisoil, water flows to plant

Water Movement: Soil to Plant

Water Regulation on Land

• Terrestrial organism challenges:– Evaporative loss (air dry)– Access replacement water

Water Regulation on Land

Recall Energy Balance Equation: HS = Hm + Hcd + Hcv + Hr - He

Now: one for water…

Water Regulation: Plants• Wip= Wr + Wa - Wt - Ws

• Wip= Plant internal water• Wr = Roots (+)• Wa = Air (+: humid spots)• Wt = Transpiration

(evaporation from tissues)• Ws = Secretions (nectar)

Next: roots

Water Acquisition: Plants• How get water?• Wip= Wr + Wa - Wt - Ws

– Dry sites: more roots!

Plant from W.Canada grasslands

• Wia = Wd + Wf + Wa - We - Ws

• Wia= Animal internal water

• Wd = Drinking (+)

• Wf = Food (+)

• Wa = Absorbed from air (+)

• We = Evaporation (-)

• Ws = Secretions (-)

Water Regulation on Land: Animals

Focus: how get water

Water Acquisition by Animals• Wia = Wd + Wf + Wa - We - Ws

• Most land animals: get water by eating & drinking (“preformed water”)

Some watering hole photos...

Water Acquisition by Animals• Water gained via metabolism (metabolic water)

• C6H12O6 + 6O2 6CO2 + 6H2O

• Water made by aerobic respiration.

Who am I?

Water Acquisition by Animals• Wia = Wf - We – Ws

Water Acquisition by Animals• Special adaptations: behavior

• Namib desert (S. Africa)

Fog from Atlantic

Lizard flashback

Water Acquisition by Animals• Onymacris beetle