Lecture 3: Biological Designs

Question 1

An animals ultimate design determined by nature must address what?

Answer 1

The physical demands it faces

Question 2

Stress

Answer 2

Force applied to a material (gravity)

Question 3

Strain

Answer 3

Deformation in a material caused by stress

Question 4

Scaling effects

Answer 4

Consequences of size animal must deal with

Question 5

Allometry

Answer 5

The change in an organism’s shape or proportions concomitant to a change in size

Question 6

Scaling

Answer 6

The study of size and its consequences

Question 7

Otogenic scaling

Answer 7

Scaling related to development

Question 8

Phylogenic scaling

Answer 8

Scaling related to evolutionary relationships

Question 9

Static Scaling

Answer 9

Looking at the organism as it is

Question 10

How does enlargement of a body part affect an organism?

Answer 10

It places additional demands on the organism (often disproportionally)

1. Mass increases stress on skeletal elements
2. Increased oxygen and nutritional demands

Question 11

Units for length

Answer 11

mm, cm, or m

Question 12

Units for area

Answer 12

mm^2, cm^2, or m^2

Question 13

Units for volume

Answer 13

mm^3, cm^3, or m^3

Question 14

Given no change in an organism’s shape, how can even the smallest increments in length affect the area and volume of the body?

Answer 14

Area and volume will increase exponentially

Question 15

How does an increase in volume affect the organism?

Answer 15

An increase in volume causes an increase in mass. This may lead to differences (disproportions) between the body and appendages.

Question 16

Scaling independent features

Answer 16

A biologic feature independent of overall size and mass of the organism

Question 17

What features are relatively independent of the effects of scaling?

Answer 17

1. Size of red blood cells between organisms
2. Muscle strength per square inch
3. Biochemical properties of blood
4. Body temperature
5. Rate of muscle contraction
6. The proportion of blood that is red blood cells and liquid plasma

Question 18

Isometric

Answer 18

Two bodies (or two body parts) with the same proportions. Example: Legs

Question 19

Allometric

Answer 19

Two bodies (or parts of bodies) with different proportions (that is, non-isometric), that changes in proportion to mathematical or natural rules

Question 20

What does the allometric equation (Y=bx^a) represent?

Answer 20

Y = one of a paired measurement
X = the second of a paired measurement, plotted on exponential axis
b= constant (Y intercept)
a = slope

Question 21

If a~1, what is the allometric relationship?

Answer 21

Directly proportional
–Body weight: heart weight
–Body weight: lung weight
–Body weight to blood volume (ml)
–Body weight to skeletal mass

Question 22

Negative allometries (a<1)

Answer 22

Relatively slower growing or becoming relatively smaller

–Body size (mass) : metabolic rate

Question 23

Positive allometries (a>1)

Answer 23

Relatively faster growing or becoming relatively larger

–Beak length in shore birds: head size

Question 24

Isometry

Answer 24

Body parts remain relatively constant as growth occurs or as species evolve

Question 25

What relevance did the Titanotheres have to this unit?

Answer 25

1. The length of the horn on the skull increased with progressive evolutionary forms
2. Fossil record shows that there was a positive bias in the direction of a larger horn-similar in other horned lineages
3. This provides advantages in attracting and fighting over mates

Question 26

What does Kleiber’s Law outline?

Answer 26

The negative allometric relationship between body mass (weight) and metabolic rate (e.g., oxygen consumption, body heat production).

Question 27

For the mast majority of animals, how does the metabolic rate scale to the animal’s mass?

Answer 27

Metabolic rate scales to the ¾ power of the animal’s mass

Question 28

Is basal metabolic rate higher in smaller or larger animals?

Answer 28

Smaller

Question 29

What is a key thing basal metabolic rate affects?

Answer 29

Nutritional needs

Question 30

Scaling of heart rate

Answer 30

Heart rate has negative n ^-¼ relationship (the larger the animal the slower the heart rate)

Question 31

Scaling of life span

Answer 31

Lifespan has a positive n^ +1/4 relationship (the larger the animal the longer the life span)

Question 32

What are allometric calculators used for?

Answer 32

To determine drug dosing for different sized people (calculated by actual vs. ideal body weight) and animals of different sizes (being careful to consider differences in how drugs are metabolized)

Question 33

What are some physiologic processes that depend on surface area?

Answer 33

Digestion, respiration, & chewing

Question 34

Is more or less surface area better in general?

Answer 34

More

Question 35

Inertia

Answer 35

Every body is maintained in a state of rest until a new force acts to put it into motion. Resistance to change

Question 36

Change in motion is proportional to what?

Answer 36

The force put on it

F = ma

Question 37

What are longstanding effects of weight?

Answer 37

1. Deterioration of weight bearing joints (hips, knees etc)
2. Remodeling of bone
3. Stress fractures

Question 38

Hypertrophy

Answer 38

Increase in the mass of a cell (tissue)

Question 39

Atrophy

Answer 39

Loss of tissue substance

Question 40

How does biological design effect evolution?

Answer 40

Mutations arise, provide a source of genetic variation in an organisms traits. Natural selection acts on these traits, favoring those that are compatible with current environmental conditions and acting against traits that are not compatible