SUBMITTED BY – SURJEET & RAVINDER

SUBMITTED TO – Dr. PARDEEP BAMAL

INTRODUCTIONEcology is the scientific study of the

relationships that living organisms have with each other and with their natural environment

There are some ecological rules which decide the animal survivability in their habitat.

There are 4 rules-1. ALLEN’S RULE

2. BERGMANN’S RULE

3. GOLGER’S RULE

4. WILSON’S RULE

ALLEN’S RULEAllen's rule is a biological rule

posited by Joel Allen in 1877. It states that endotherms from colder climates usually have shorter limbs (or appendages) than the equivalent animals from warmer climates.

Jackrabbit- long ears,legs and face

ArcticHare- short ears,legs and small face

The theory behind Allen's rule is that endothermic animals with the same volume may have differing surface areas, which will aid or impede their temperature regulation.

In cold climates, the greater the exposed surface area, the greater the loss of heat and therefore energy. Animals in cold climates need to conserve as much energy as possible.

In warm climates, the opposite is true. An animal will overheat quickly if it has a low surface area to volume ratio. Therefore, animals in warm climates will have high surface area to volume ratios so as to help them lose heat.

BERGMANN’S RULEGiven by Christian Bergmann.

In fact, Bergmann's Rule asserts that geographic races of a species possessing smaller body size are found in the warmer parts of the range, and races of larger body size in cooler parts.

EXPLANATIONIn cold climate, larger animals have a lower

surface area to volume ratio than smaller animals, so they radiate less body heat per unit of mass, and therefore stay warmer in cold climates.

In hot climate, the higher surface area-to-volume ratio of smaller animal facilitates heat loss through the skin and helps cool the body.

e.g. polar bears are much larger than spectacled bears.

EXTENSION OF BERGMANN’ RULEIn 1937 German zoologist and ecologist

Richard Hesse proposed an extension of Bergmann's rule. 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.

GOlGER’ RULEGolger's Rule is a zoological rule

which states that within a species of endotherms, more heavily pigmented forms tend to be found in more humid environments, e.g. near the equator.

It was named after the zoologist Lambert Golger.

EXPLANATIONIn this case, the underlying cause is

probably the need to better protect against excessive solar UV radiation at lower latitudes. However absorption of a certain amount of UV radiation is necessary for the production of certain vitamins, notably vitamin D.

For e.g. in the case of birds appears to be the increased resistance of dark feathers to feather- or hair-degrading bacteria such as Bacillus licheniformis. Feathers in humid environments have a greater bacterial load, and humid environments are more suitable for microbial growth; dark feathers or hair are more difficult to break down.

WILSON’S RULEAnimal living in the arctic region have

thick layer of subcutaneous fat compared to lean skin of animals in tropical habitats.

Animals have longer hairs in arctic region as compared to hotter climate animals.

For e.g. sheep and goats in colder climate have long hairs and thick subcutaneous fat than hot climate animals.