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Behavioural Strategies of Adaptations in Animals

Adaptation	Example	Process and mechanism
Hibernation	Northern ground squirrels	Sleep during winter; body temperature drops, breathing and heart beat becomes slow.
Aestivation	Ground squirrels in southwest deserts	Avoids heat by spending dry-hot period in a torpid state into burrows.
Camouflage	Praying mantis	Mimics a dead leaf and resembles background vegetation.

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Altitude sickness is an illness due to low atmospheric pressure at high altitudes. It is characterised by nausea , fatigue and heart palpitation. The body does not get enough oxygen.

The body recovers from it by increasing red blood cell production, decreasing the binding affinity of hemoglobin and by increasing breathing rate.

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(i) Biotic potential is the maximum reproductive capacity of an organism under optimum environmental conditions. If the biotic potential is high then the populaltion growth rate is increased.

(ii) Environmental resistance. The factors such as shortage of food, disease, predation, environmental natural calamities which impose a check on population size constitute environmental resistance. Environmental resistance decreases the rate of population growth.

(iii) Carrying capacity. It is a measure of the feeding capacity of an environment or ecosystem for a population of a species under a given set of conditions. If the population reaches its carrying capacity then the no further growth of the pooulation takes place.

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Organisms living in polar regions have to face the severe winter and show different types of adaptations.
(i) They have thick fur and more amount of fat for insulation from the cold.

(ii) During extreme winter they undergo hibernation during which their metabolic activities slow down and they sleep for a long period to avoid the harsh cold condition.

(iii) They have shorter ears and limbs to minimise heat loss.

 

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(a) Birth or Natality rate. It is generally expressed as number or births per 1,000 individuals of a population per year. It increases the population size (total number of individuals of a population) and population density.

In a population these rates refer to per capita births.

Example. If in a pond there are 20 plants last year as through reproduction

In a population these rates refer to per capita births.

Example. If in a pond there are 20 plants last year as through reproduction 8 new plants are added. Taking the current population to 28 we calculate birth rate as F/20 = 0.4 offspring per plant.

(b) Attributes which a population shows and not individual.

1. Death ratio.

2. Sex Ratio.