A comparison of the bergmann and allan rule and their complimentary nature

Open in a separate window Primary driver causal driver of change: MS, museum specimen; FD, field observations through time.

A comparison of the bergmann and allan rule and their complimentary nature

Data demonstrating such a relationship in Swedish moose Eurasian elk are shown. Although originally formulated in terms of species within a genus, it has often been recast in terms of populations within a species.

It is also often cast in terms of latitude.

Laws of thermodynamics

It is possible that the rule also applies to some plants, such as Rapicactus. The rule is named after nineteenth century German biologist Carl Bergmannwho described the pattern inalthough he was not the first to notice it. Bergmann's rule is most often applied to mammals and birds which are endothermsbut some researchers have also found evidence for the rule in studies of ectothermic species.

While Bergmann's rule appears to hold true for many mammals and birds, there are exceptions. This perhaps reflects a reduced ability to avoid stressful environments, such as by burrowing. Newman inNative American populations are generally consistent with Bergmann's rule although the cold climate and small body size combination of the Eastern Eskimo, Canoe Indians, Yuki peopleAndes natives and Harrison Lake Lillouet runs contrary to the expectations of Bergmann's rule.

Warmer climates impose the opposite problem: It is important to note that when analyzing Bergmann's Rule in the field that groups of populations being studied are of different thermal environments, and also have been separated long enough to genetically differentiate in response to these thermal conditions.

Hesse's rule, also known as the heart—weight rule, states that species inhabiting colder climates have a larger heart in relation to body weight than closely related species inhabiting warmer climates.

Some believe that latitude itself is a poor predictor of body mass. Examples of other selective factors that may contribute to body mass changes are the size of food items available, effects of body size on success as a predatoreffects of body size on vulnerability to predation, and resource availability.

For example, if an organism is adapted to tolerate cold temperatures, it may also tolerate periods of food shortage, due to correlation between cold temperature and food scarcity.

Resource availability is a major constraint on the overall success of many organisms. Resource scarcity can limit the total number of organisms in a habitat, and over time can also cause organisms to adapt by becoming smaller in body size.

Since Rapicactus grow in a distributional area in which average precipitation tends to diminish at higher latitudes, and their body size is not conditioned by climatic variables, this could suggest a possible Bergmann trend.as a Pennsylvania district judge ruled in a case, ID violates the ground rules of science by invoking supernatural causation and making assertions that cannot be tested or falsified, and thus does not belong in a school's science curriculum.

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On the validity of Bergmann’s rule Shai Meiri* and Tamar Dayan Department of Zoology, Tel Aviv University, Tel Aviv, Israel Abstract Aim We reviewed the occurrence of Bergmann’s rule in birds (ninety-four species) and. Adapting to Climate Extremes: Carl Bergmann and Joel Allen, formulated rules concerning these factors.

Wei Cheng timberdesignmag.com reported that some human nerve cells have proteins on their surfaces that enable the m to differentiate between several different temperatures in the mildly warm to hot range.

This sensing ability may play an important. Bergmann's rule generally holds for people as well. A study of human populations during the early 's showed a strong negative correlation between body .

A comparison of the bergmann and allan rule and their complimentary nature

Even though many studies testing Bergmann's rule have focused on intraspecific comparisons [19, 34, 37, 73, 98, 99], the rule [6, 21, 23] was originally developed on the basis of multiple species comparisons which is the approach that we took.

Capsule An analysis of body mass and wing length for four bird species shows trends broadly in line with predictions from Bergmann's and Allen's rules but with species- and sex-specific trends in terms of body size variation with latitude in Britain.

Human Biological Adaptability: Adapting to Climate Extremes