To make Environmental Inferences out-of Body Size and you will Temperature
- March 7, 2023
- Dresden Decor
The rate at which organisms process energy and materials determines how fast they grow and reproduce, how long they live, and how rapidly they move through space. Thus it is not surprising that a number of key ecological traits depend on body mass and temperature. For example, John Damuth hypothesized that the maximumimal population abundance (or carrying capacity, large K) that a species can achieve is determined by how much energy is available (Eoverall) and how much energy is used by each personal (Eindividual), so that Etotal is proportional to KEindividual. Because Eindividual is hookupdaddy.net/best-hookup-apps proportional to body mass raised to an exponent b (Mb where b ? 3/4), then Etotal is proportional to KM 3/4 , and K is proportional to EtotalM -3/4 .
This relationship, called the energy equivalence rule, tells you two things: 1. mice can reach higher abundances than elephants and 2. if the populations of elephants and mice are at their carrying capacity, these populations will use the same amount of energy (KEindividual is proportional M -3/4 + 3/4 = M 0 ). The relationship works well when a large number of species, including a very broad range of body sizes from all over the globe, are plotted together, probably because a sufficiently large number of species close to their carrying capacity are represented.
Another important ecological trait that is influenced by body size and temperature is rmax, the intrinsic rate of population increase (i.e., the rate at which populations can grow in the absence of food or space limitations). We have known for a very long time that populations of small animals can grow faster than those of large ones. More precisely, ecologists found that rmax is proportional to M -b . In 1974, Tom Fenchel conjectured that the value of rmax would be set by the organism’s mass-specific metabolic rate (i.e., the ratio of metabolic rate to body mass), and hence that b should be about -0.25. In 2004, Vance Savage and his collaborators hypothesized that rmax would depend on both body mass and temperature. Both conjectures proved to be roughly correct (Figure 5). Both the maximal rates at which populations can grow and their potential carrying capacity are influenced by body size and temperature. Ecologists have documented similar effects for processes as disparate in scale as molecules evolving, and the flow of energy and materials through ecosystems. Temperature and size affect how organisms work because organisms cannot break the limits imposed on them by physics and chemistry. The physical and chemical principles that rule the transfer of energy and materials within and among organisms generate order in the riotous, and sometimes seemingly overwhelming, complexity of ecological systems.
Frazier, Yards., Huey, R. B. mais aussi al. Thermodynamics constrains the fresh new progression out of bug population progress costs: “hotter is ideal”. American Naturalist 168, 512–520 (2006).
Gillooly, J. F., Brownish, J. H. et al. Aftereffects of dimensions and you may temperature on kcalorie burning. Technology 293, 2248–2251 (2001).
For the Numbers 2 and you will 3, activities away from 10 along side axes is actually separated of the same distance: one hundred kg can be from 10 kilogram because the 10 kilogram is actually from one kilogram. Hence, we find a large number of top features of pets and you can herbs one to desire ecologists are very different since the fuel services from system size. The analysis of these dating is called allometry additionally the equations you to connect a keen organism’s element which have looks bulk have been called allometric equations (throughout the Greek root allo for example “other” and you will meter meaning that “measure”). Whenever bacteria follow the principle off geometric similarity discussed significantly more than, upcoming we refer to the relationship anywhere between a trait and body size just like the isometric. Such, the relationship between surface and body bulk is actually isometric.