Allometry - Wikipedia
Definition of allometry - the growth of body parts at different rates, resulting in a change of body proportions. Allometry The relationship of the growth of one part of an organism to the One of the best known examples of non-isometric growth is human growth. . A Dictionary of Zoology , originally published by Oxford University Press However, more recently the meaning of the term allometry has been modified and expanded to refer to biological scaling relationships in general, be it for.
ALLOMETRY - Definition and synonyms of allometry in the English dictionary
This is the slope of a straight line, but most data gathered in science do not fall neatly in a straight line, so data transformations are useful. It is also important to keep in mind what is being compared in the data. Comparing a characteristic such as head length to head width might yield different results from comparing head length to body length. That is, different characteristics may scale differently. There are two reasons for log transformation - a biological reason and a statistical reason.
Biologically, log-log transformation places numbers into a geometric domain so that proportional deviations are represented consistently, independent of the scale and units of measurement. In biology this is appropriate because many biological phenomena e. This will normalize the data set and make it easier to analyze trends using the slope of the line.
Meaning of "allometry" in the English dictionary
Sometimes the two analyses can yield different results, but often they do not. If the expected slope is outside the confidence intervals, then there is allometry present. If mass in this imaginary animal scaled with a slope of 5 and this was a statistically significant value, then mass would scale very fast in this animal versus the expected value.
It would scale with positive allometry. If the expected slope were 3 and in reality in a certain organism mass scaled with 1 assuming this slope is statistically significantthen it would be negatively allometric.
Force is dependent on the cross-sectional area of muscle CSAwhich is L2. If comparing force to a length, then the expected slope is 2. Alternatively, this analysis may be accomplished with a power regression.
Plot the relationship between the data onto a graph. Fit this to a power curve depending on the stats program, this can be done multiple waysand it will give an equation with the form: The downside, to this form of analysis, is that it makes it a little more difficult to do statistical analyses.What is PHUBBING? What does PHUBBING mean? PHUBBING meaning, definition & explanation
Physiological scaling[ edit ] Many physiological and biochemical processes such as heart rate, respiration rate or the maximum reproduction rate show scaling, mostly associated with the ratio between surface area and mass or volume of the animal. Metabolic rate and body mass[ edit ] In plotting an animal's basal metabolic rate BMR against the animal's own body mass, a logarithmic straight line is obtained, indicating a power-law dependence.
If muscle mass and bone mass did not increase more rapidly than the mass of the body as a whole, the human body would become unstable and unable to support its own weight. On the other hand, metabolic rates and the heat produced by metabolism increase less rapidly than total body height, since the larger volume-to-surface-area ratio means that less heat is lost through the skin.
allometric | Definition of allometric in English by Oxford Dictionaries
In humans, a percent increase in height produces a 73 percent increase in metabolic heat production. Another example of allometric growth is seen in male fiddler crabs, Uca pugnax.
These crabs are so named because of their one large claw and "pugnacious" attitude pugnare means "to fight" in Latin. In small males, the two claws are of equal weight, each containing about one-twelfth of the total weight of the crab.
However, the size of the large claw increases disproportionately to the growth of the rest of the animal, producing in larger males a claw that may contain two-fifths of the total weight of the crab. Allometric growth is usually detected by graphing the growth data on a log-log plot. That is, the horizontal and vertical axes of the graph are both logarithmic scales.
The general allometric growth equation has the form y axk.
- Meaning of "allometric" in the English dictionary
Taking the logarithm of both sides produces the following equation: This equation has the basic form of a linear equation in slope-intercept form, y mx b. If the body mass of Uca pugnax is plotted on the x-axis and the claw mass is plotted on the y-axis of a log-log plot, then the result will be a straight line whose slope is the relative growth rate of claw mass to body mass.
In the male Uca pugnax, the ratio is 6: This means that the mass of the big claw increases six times faster than the mass of the rest of the body. In females, the claw grows isometrically and remains about 8 percent of the body weight throughout growth. Allometric growth occurs only in males. Allometric growth is also seen in nonhuman primates.
For example, the jaw and other facial structures of baboons have a growth rate about four and one-quarter times that of the skull.