Site Loader
Rock Street, San Francisco

 

 

 

 

 

Comparison
of the Ratios of Limb Growth in Newborn and Adult Humans to Determine Isometric
or Allometric Growth

William
Sheehy

We Will Write a Custom Essay Specifically
For You For Only $13.90/page!


order now

Abstract: The head circumference
ratio of the adult shows that limbs do grow at a different rate when compared
to the newborn ratio. Though one ratio of an adult might be similar to that of
the ratio of a newborn, the fact that another tested limb differs supports the hypothesis
that humans grow allometricly.

 

 

 

 

 

 

Introduction:

This experiment determines
the classification of which humans develop. The prefix “allo-” means “indicating
difference, variation, or opposition”(Dictionairy.com 2018).  Allometric growth is that of limbs growing
disproportionately, or with that of different ratios. Isometric growth, being
opposite of Allometric, is when that ratio of limb growth is the same. When
determining whether a limb grows in an Isometric or Allometric fashion, we
compare the overall height of the newborn or adult and divide it by the length
of a limb (head circumference and upper limb length, used in the case of this
experiment). Once the ratios are found, they are compared, and the results
determine whether humans grow in either an Allometric or Isometric fashion.

A good example of
Allometric growth in nature would be the Pacific oyster, whose shell grows at
disproportionate rates in medium growth sites, when compared to its regular
growth of body weight, depending on the nutrients available and the salinity of
the environment (Brown, James & Hartwick, Brian, 1988).

The measurements taken in
this experiment (dependent variables) are the upper limb length, head
circumference, and height. These were compared to find the ratio between them. Then,
the ratios are compared to the ratios of newborns’ (The independent variable). Some
limiting factors (control variables) were that of the gender, age, ethnicity,
and upbringing of the test subjects. For the newborns, a predetermined average
measurement table was used, and the adults were all above the age of 18 (Level
of Treatment)

Hypothesis
1
– The ratio between height and head circumference is different between newborns
and adults, so humans grow in an Allometric fashion

Prediction
1
– If the ratio is different between the height and head circumference in adults
when compared to newborns, then humans grow in an Allometric manner

Hypothesis
2
– The ratio between height and upper limb length is different between newborns
and adults, so humans grow in an Allometric fashion

Prediction
2
– If the ratio is different between the height and upper limb length in adults
when compared to newborns, then humans grow in an Allometric manner

 

Method:
The materials used in this experiment were a meter stick to record the
measurements of the test subjects, and a piece of string to record the head
circumference. In a group of 4, the measurements of height, head circumference,
and upper limb length were measured. Each measurement was rounded to the
nearest .5cm.  The meter stick was used
to measure the heights of each subject and those heights were recorded, while
some used a previous knowledge of their height and converted inches to cm (1in
= 2.54cm). The meter stick was used to record the length between the center
joint of their shoulder and the tip of their middle finger. The piece of string
was used, wrapped around the widest part of a subject’s head, to record head
circumference. After these measurements were done, the ratios were determined
by dividing the height by the selected body part. This was done for each group
member (4). The collected data was then pooled into a spreadsheet displaying
the results of the entire test subject pool (class) (Professor D. John 2016)

 

 

Results:

Subject

Height
(cm)

Upper
Limb Length(cm)

Head
Circumference(cm)

Ratio
(Height/Upper)

Ratio
(Height/Head
Circ.)

1

 

60.5

55

2.69

2.96

2

168

65

56

2.58

3

3

155

62

58

2.5

2.67

4

160

62

56

2.58

2.86

Newborn

48

20

33

2.4

1.45

Student #

1

2

3

4

5

6

7

8

Upper Limb

2.168

2.325

2.334

2.438

2.69

2.58

2.5

2.58

Head Circumference

2.751

2.871

2.708

2.732

2.96

3

2.67

2.86

 

 

 

 

 

 

 

 

 

Student #

9

10

11

12

13

14

15

16

Upper Limb

2.51

2.35

2.26

2.66

2.23

2.4

2.4

2.5

Head Circumference

2.88

3.08

3

2.95

2.76

3

3.2

2.8

 

 

 

 

 

 

 

 

 

Student #

17

18

19

20

 

 

Average Ratio

Newborn

Upper Limb

2.6

2.4

2.2

2.3

 

 

2.42125

2.4

Head Circumference

2.8

2.7

3.1

3

 

 

2.8911

1.45

 Table 1: The Group Measurements of Height,
Upper Limb Length and Head Circumference and Ratios (Height v Body part).
Newborn data added for comparison, subject pool of 4

Table 2: The Class
Ratios of Height Vs Upper Limb Length, and Height Vs Head Circumference, with
an Average of the Ratios (Height v Body Part) for Adults. Newborn data  added/

Graph 1 : The Class
Ratios of Height Vs Upper Limb Length, and Height Vs Head Circumference

 

Graph 2: Average of the
Ratios (Height v Body Part) for Adults. Newborn data added for comparison

In this experiment the
average ratio was found to be 2.42125 (Table 2) for height to upper limb. It
was also found that the average ratio for height to head circumference was
2.8911 (Table 2). The ratio of height to upper limb for newborn was
predetermined to be 2.4 (Table 2). The ratio of height to head circumference in
newborns was predetermined to be 1.45 (Table 2).

Conclusion:

Hypothesis 1 was that the
ratio between height and head circumference is different between newborns and
adults, so humans grow in an Allometric fashion. This hypothesis was supported
by the Head circumference average in adults, 2.8911 (Table
2), being significantly different from the newborns’ ratio, 1.4 (Table 2).
Hypothesis 2 was that the ratio between height and upper limb length is
different between newborns and adults, so humans grow in an Allometric fashion.
This hypothesis was not supported by the found data as the average upper limb
length ratio in adults, 2.42125 (Table 2), was very similar to the newborns’
ratio, 2.4 (Table 2).

This experiment
supported the idea that humans grow allometricly. While some data suggested a
different conclusion, we can still support the hypothesis through the averages
shown, specifically the Head circumference ratio. Even at the smallest level of
nature we can find like Allometric patterns. For example, Allosteric Regulation
is when a regulatory molecule binds at a location and changes the shape of an
enzyme. (Freeman, Quillin, Allison, Black, Podgorski, Taylor 2017) This is
referred to as “Allosteric” because of the change that occurred. The Head
Circumference ratio shows that limbs do grow at a different rate. Though one
ratio of an adult might be similar to that of the ratio of a newborn, the fact
that another tested limb differs supports the idea that humans grow
allometricly.

There was quite a bit
of room for error in this experiment. Very different results would have been
found if different body parts were chosen, or if two similar body parts were
chosen (could have been upper limb length and wing span). Some measurement
errors also arose, seeing as the string used to calculate head circumference
needed to be stretched to the meter stick it could have also been measured
incorrectly, or it could have been being measured at the wrong part of the
head. To improve the results, more body parts need to be compared and perhaps a
demonstration prepared to show how to measure the head circumference correctly,
to eliminate any errors.

One could compare
averaged ratios of an adult group (body parts to be determined) to the newborn
data and change the Level of treatment so that, for example, only males are
measured, or to separate the genders and compare the ratios to that of Male v
Female. For example, one could hypothesize that “Limb growth in adult males and
adult females differ; with the females growing at a more proportionate rate in
comparison to the males.”

References:

“allo-“.
Dictionary.com Unabridged. Random House, Inc. 20 Jan. 2018. .

Freeman, Quillin,
Allison, Black, Podgorski, Taylor. Biological Science 6th Edition
Pearson 2017 pp 183

Brown, James &
Hartwick, Brian. Influences of temperature, salinity and available food upon
suspended culture of the Pacific oyster, Crassostrea gigasI. Absolute and
allometric growth. Aquaculture. 1988. 70. 231-251.
10.1016/0044-8486(88)90099-3.

Professor D. John
“Scientific Investigation” in BSC Laboratory Manual USF St.Petersburg Pearson
2016 pp 3-31

Post Author: admin

x

Hi!
I'm Velma!

Would you like to get a custom essay? How about receiving a customized one?

Check it out