This document discusses four ecological rules: 1. Allen's rule - animals in colder climates have shorter appendages to conserve heat. 2. Bergmann's rule - within a species, individuals are larger in colder climates to reduce heat loss. 3. Gloger's rule - within a species, darker pigmentation occurs in more humid environments to protect against UV radiation. 4. Wilson's rule - arctic animals have thicker insulation like fat and fur compared to animals in tropical regions.

1. SUBMITTED BY – SURJEET &
RAVINDER
SUBMITTED TO – Dr. PARDEEP
BAMAL

2. INTRODUCTION
Ecology 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.

3. There are 4 rules-
1. ALLEN’S RULE
2. BERGMANN’S RULE
3. GOLGER’S RULE
4. WILSON’S RULE

4. ALLEN’S RULE
Allen'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.

5. Jackrabbit- long ears,legs
and face
ArcticHare- short ears,legs
and small face

6. 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.

7. 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.

8. BERGMANN’S RULE
Given 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.

9. EXPLANATION
In 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.

11. EXTENSION OF BERGMANN’ RULE
In 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.

12. GOlGER’ RULE
Golger'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.

13. EXPLANATION
In 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.

14. 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.

15. WILSON’S RULE
Animal 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.