22/06/2021
Course BBS2061 Allometry
Pluis, CMH
22/06/2021 Pluis, CMH 1
Lecture 1
Pluis, CMH
22/06/2021 Pluis, CMH 2
1
, 22/06/2021
Lecture 1 - Opening
• What is the relevance of Allometry for Biomedical Sciences?
• Extrapolation from mouse to human
• Assessment of / correction for influence of body size in human studies
• Size range in biomedical research
• Patients: scale is between newborns and adults
• Biomedical research: scale is between mouse and human
• Biological research: scale is between smallest animal (C. Elegans Drosophila) and largest
animal (horse)
22/06/2021 Pluis, CMH 3
Lecture 1 - Opening
• Genetic principles are studies in mice.
• Then, translation research in, for instance, a goat (large animals correspond more
with humans than small animals such as mice).
• Then, clinical practice in humans.
22/06/2021 Pluis, CMH 4
2
, 22/06/2021
The exponential form is y = ax^b, as you say and the logarithmic form
is log(y) = log(a) + b*log(x). It's the same formula, just written
Lecture 2 differently using the rules for logarithms, and so the meaning of b also
doesn't change. However, the interpretation that b>1 means positive
allometry and b<1 means negative allometry is only valid when you
compare like dimensions (e.g. length to length, area to area). As you
Pluis, CMH can see in the examples in the opening lecture, when you are
comparing a surface area to a volume (or body mass), you would
expect b = 2/3 for isometry, b < 2/3 for negative allometry and b > 2/3
for positive allometry. For many relations (e.g. longevity vs. body
mass), it is not possible to define when a relation would be isometric...
22/06/2021 Pluis, CMH 5
Lecture 2 – Introduction to Allometry
• Allometry describes how the characteristics of leaving creatures change with size
• Old definition:
• Allometry describes the scaling relationship between the size of a body part and the size of
the body as whole, as both grow during development
• Recently, its definition has changed
• Allometry describes the biological scaling relationships in general
• An increase in size may require a change in design
• For example: bridge or locomotion in swimming animals
22/06/2021 Pluis, CMH 6
3
, 22/06/2021
Lecture 2 – Introduction to Allometry
• Because differences in gender, age and body
mass may affect the outcome measure,
there is correction for body size in clinical
practice
• For example in renal function and pulmonary
function
• Example: ear
• Large animals are sensitive for lower frequencies
• For example, elephant: transmissions of low-
frequency waves via ground which are detected
by feet
• Small animals are sensitive for higher
frequencies
22/06/2021 Pluis, CMH 7
Lecture 2 – Introduction to Allometry
• History of Allometry
• Leonardo Da Vinci
• Throughout his life, da Vinci studied anatomy
• Differences in ganglion cells between species
22/06/2021 Pluis, CMH 8
4
Course BBS2061 Allometry
Pluis, CMH
22/06/2021 Pluis, CMH 1
Lecture 1
Pluis, CMH
22/06/2021 Pluis, CMH 2
1
, 22/06/2021
Lecture 1 - Opening
• What is the relevance of Allometry for Biomedical Sciences?
• Extrapolation from mouse to human
• Assessment of / correction for influence of body size in human studies
• Size range in biomedical research
• Patients: scale is between newborns and adults
• Biomedical research: scale is between mouse and human
• Biological research: scale is between smallest animal (C. Elegans Drosophila) and largest
animal (horse)
22/06/2021 Pluis, CMH 3
Lecture 1 - Opening
• Genetic principles are studies in mice.
• Then, translation research in, for instance, a goat (large animals correspond more
with humans than small animals such as mice).
• Then, clinical practice in humans.
22/06/2021 Pluis, CMH 4
2
, 22/06/2021
The exponential form is y = ax^b, as you say and the logarithmic form
is log(y) = log(a) + b*log(x). It's the same formula, just written
Lecture 2 differently using the rules for logarithms, and so the meaning of b also
doesn't change. However, the interpretation that b>1 means positive
allometry and b<1 means negative allometry is only valid when you
compare like dimensions (e.g. length to length, area to area). As you
Pluis, CMH can see in the examples in the opening lecture, when you are
comparing a surface area to a volume (or body mass), you would
expect b = 2/3 for isometry, b < 2/3 for negative allometry and b > 2/3
for positive allometry. For many relations (e.g. longevity vs. body
mass), it is not possible to define when a relation would be isometric...
22/06/2021 Pluis, CMH 5
Lecture 2 – Introduction to Allometry
• Allometry describes how the characteristics of leaving creatures change with size
• Old definition:
• Allometry describes the scaling relationship between the size of a body part and the size of
the body as whole, as both grow during development
• Recently, its definition has changed
• Allometry describes the biological scaling relationships in general
• An increase in size may require a change in design
• For example: bridge or locomotion in swimming animals
22/06/2021 Pluis, CMH 6
3
, 22/06/2021
Lecture 2 – Introduction to Allometry
• Because differences in gender, age and body
mass may affect the outcome measure,
there is correction for body size in clinical
practice
• For example in renal function and pulmonary
function
• Example: ear
• Large animals are sensitive for lower frequencies
• For example, elephant: transmissions of low-
frequency waves via ground which are detected
by feet
• Small animals are sensitive for higher
frequencies
22/06/2021 Pluis, CMH 7
Lecture 2 – Introduction to Allometry
• History of Allometry
• Leonardo Da Vinci
• Throughout his life, da Vinci studied anatomy
• Differences in ganglion cells between species
22/06/2021 Pluis, CMH 8
4
