Intro to Thermal Physiology - Exam 2

Comparative Animal Physiology - Lecture 8

Temperature

Major player in pretty much all broad categories of physiological processes, even most fundamental.

Deals with the way all chemical reactions proceed in our body and the ability of organisms to use their tissues to perform work.

Mitonuclear interactions/coadaption

Both nuclear and mitochondrial DNA code for parts of membrane proteins in ETC and oxygenated phosphorus.

Reactive oxygen species (ROS)

Certain mismatch combinations between nuclear genes and mitochondrial genes can produce more of these, which increases oxidative stress.

Endotherm

Animal whose body tissues are significantly warmed by its own metabolic heat.

Ectotherm

Animal whose body tissues aren't significantly warmed by its own metabolic heat.

Homeotherm (aka “thermoregulator”)

Animal whose body temp is relatively invariant because its homeostatically regulated

Poikilotherm (aka “thermoconformer”)

Animal whose body temp varies considerably with ambient temperature.

Poikilothermic ectotherms

No thermogenesis or thermoregulation. Ex: fish and insects

Poikilothermic Endotherms

Thermogenesis, but no thermoregulation. Ex: naked mole rats

Homeothermic Ectotherms

Thermoregulation, but no thermogenesis. Ex: gopher tortoises

Homeothermic Endotherms

Thermogenesis and thermoregulation. Ex: birds and most mammals

Heterotherm

Animal that employs more than one thermoregulatory or endothermic strategy.

Temporal Heterothermy

Animal whose thermoregulatory or endothermic strategy charges over time.

Regional heterothermy

Animal whose thermoregulatory or endothermic strategy is different in different parts of body.

Ta

Ambient/environmental temperature

Ts

Surface body temperature. For small animals, this is the dominating force for heat

CTmin

lower thermal limit of performance

Inflection point

thermal performance curve switches between accelerating upwards to decelerating upwards

Topt

temperature at which Tb is maximized; upwards deviations from this can be much more costly to fitness

Tolerance range

temperature range between CTmin and CTmax

Tbr

warming tolerance; temperature range at half of maximum (CTmax/2)

CTmax

upper thermal limit of performance

1. CT min

2. Inflection point

3. Tbody

4. Ta

5. warming tolerance

6. Topt

7. CTmax

8. Thermal safety margin

9. Tolerance range

Label aspects of temperature performance curve (TPC)

1. ectothermic poikilotherm

2. endothermic homeotherm

Label the TPCs by the kind of thermal strategies that produce them

heat

type of energy that substance possesses by virtue of those atomic motions, so both relative mass and relative temperature matters to understanding movement of it

energy balances

Because heat's type of energy, we tend to model heat transfer between animals and its environment through (blank)

0 = energy in - energy out and 0 = heat in-heat out; 0= heat in- heat out+heat source

According to energy balances, without source, 0 = (blank) and (blank), and with source, 0= (blank)

Incoming and reflected solar radiation

affects Tb (body temperature) at high frequency; largely in UV spectrum

Radioactive heat transfer from ground, trees, plants, another animal, etc.

affects Tb (body temperature) at low frequency; in infrared or lower spectrum

albido

reflectance of solar radiation; animal surface property

Solar input

radiation energy/area; affected by time of year and location on earth

conduction

transfer of heat from directly contacted solid; affects Tb (body temperature)

convection

affects Tb (body temperature); transfer of heat from directly contacted fluid

Ta and Ts

Whether heat is gained or lost and how quickly depends on difference between (blank) and (blank)

evaporative heat loss

water absorbs energy (heat) when it undergoes state change; increased with air speed; effectiveness as cooling mechanism depends on how saturated air is with water already

active thermoregulation

type of thermoregulation; requires continuous renergy expenditure

behavioral thermoregulation

type of thermoregulation; examples: moving back and forth between basking and taking thermal refuge, shivering to increase Tb, and sweating to reduce Tb

Passive thermoregulation

type of thermoregulation; requires only initial energy expenditure (can offset need to use or compliment active thermoregulation); ex: choosing microhabitat that's not thermally challenging, building nest, and digging burrow

membrane-lipid fluidity; fluidity; membrane phospholipid concentrations

In most fish, (blank) and body temperature have a direct relationship, but this (blank) is kept relatively constant at respective body temperatures of species by evolution of difference (Blank)

Thermoregulating

(blank) can by energetically expensive, but benefits far outweigh that

Thermal acclimation

many animals can use this to achieve wider range of functional body temps; increasing this in endotherms can boost thermogenesis; mechanisms include increasing mt/ETC activity to compensate for reduced metabolic rates (in fish) and increasing limiting enzymes; ex: rearing temperature