6/7: Flux, Metabolic rates/sizes

What are seven basic physiological challenges faced by all organisms?

1. Reproduction

2. responses to environmental changes

3. maintaining asymmetric distributions

4. utilization of energy storage

5. exchange of vital substances

6. toleration of a limited range of conditions

7. constraints by-laws

What are some characteristics specific to animals?

1. Eukaryotic

2. multicellular

3. no cell walls

4. heterotrophic, motile

5. differentiated cell types

6. from a blastula

7. sexual reproduction (mainly)

8. and tissues (not in sponges)

What are some characteristics of an exoplanet that would be able to support animal life?

Needs a motile environment, also energy sources since animals are heterotrophs

What are trade-offs?

Advantageous trait that is connected to a detrimental change in another trait

What is flux?

Flow rate of a given substance

What is a basic equation for flux?

Flux= gradient/resistance

Choose the correct answer: Flux is (directly/inversely) _____ proportional to driving force.

Directly

Choose the correct answer: Flux is (directly/inversely) _____ proportional to resistance.

Inversely

What are the units for flux?

Amount of substance per unit time (g/s, mol/hr, etc)

What does an animal's production and/or use of a vital substance differ with?

Volume (i.e. if an animal has a larger volume, they have a greater number of cells which require the same amount of vital substances)

What does an animal's rate of exchange depend on?

Surface area

Small animals have a ___ SA:V ratio.

High

Small animals are good at...

Exchanging substances with the environment

Large animals have a ___ SA:V ratio.

Low

Large animals are good at...

Retaining vital substances within the body

What is metabolic rate?

Sum of all bodily reactions

What is proxy metabolic rate?

Units/rates that can be used to serve as a metabolic rate (i.e. measuring oxygen use per minute rather than measuring ATP use)

Why would we use proxy metabolic rates?

It is vastly easier to measure and determine these rather than actual metabolic rates

Is metabolic rate constant?

No, it can vary with activity levels and therefore is usually reported in resting animals

What is unit metabolic rate?

The rate of energy use per unit of volume/mass of an animal

Small animals have ___ unit metabolic rates. Why is this?

High. They typically have to spend a lot more energy retaining vital substances in their bodies (such as heat and water)

Large animals have ___ unit metabolic rates.

Low

"Elongated" animals have ___ metabolic rates than "compact" animals.

Higher

Why are unit metabolic rates useful?

We can use this when comparing metabolic rates between animals of different sizes

How do you convert from unit MR to whole animal MR?

Multiply by the mass of the animal

How do you convert from whole animal MR to unit MR?

Divide by the mass of the animal

How can I figure out if a metabolic rate is unit vs whole animal?

UNITS! If there are units of mass in the denominator, this is a unit metabolic rate. If there are no mass constants in the denominator, it is whole animal.

Calories/min, kilocalories/hr, J/sec.

These are examples of units for ____ metabolic rates.

Whole animal

Mol/(min x mg), mol/(hr * kg).

These are example of units for ____ metabolic rates.

Unit

What are biological rules?

Generalizations about patterns of living things and their environments

What do biological rules NOT do?

Explain mechanisms or evolutionary advantages to observed patterns

What is Bergmann's rule?

Species increase in size as environmental temperature decreases

How can I remember Bergmann's rule?

Bergmann = Body size

What is Allen's rule?

Appendages of species become shorter as environmental temperature decreases

How can I remember Allen's rule?

Allen = Appendages