Population Interaction | Environment for UPSC 2025 (Pre & Mains) PDF Download

 Page 1


 
POPULATION  
INTERACTIONS 
Page 2


 
POPULATION  
INTERACTIONS 
In nature, animals, plants and microbes do not and 
cannot live in isolation but interact in various 
ways to form a biological community.  
 
Even in minimal communities, many interactive 
linkages exist, although all may not be readily 
apparent.  
 
Interspecific interactions arise from the interaction 
of populations of two different species.  
They could be beneficial, detrimental or neutral 
(neither harm nor benefit) to one of the species 
or both. 
Page 3


 
POPULATION  
INTERACTIONS 
In nature, animals, plants and microbes do not and 
cannot live in isolation but interact in various 
ways to form a biological community.  
 
Even in minimal communities, many interactive 
linkages exist, although all may not be readily 
apparent.  
 
Interspecific interactions arise from the interaction 
of populations of two different species.  
They could be beneficial, detrimental or neutral 
(neither harm nor benefit) to one of the species 
or both. 
Page 4


 
POPULATION  
INTERACTIONS 
In nature, animals, plants and microbes do not and 
cannot live in isolation but interact in various 
ways to form a biological community.  
 
Even in minimal communities, many interactive 
linkages exist, although all may not be readily 
apparent.  
 
Interspecific interactions arise from the interaction 
of populations of two different species.  
They could be beneficial, detrimental or neutral 
(neither harm nor benefit) to one of the species 
or both. 
 
Predation, parasitism and commensalisms 
share a common characteristic– the 
interacting species live closely together. 
Page 5


 
POPULATION  
INTERACTIONS 
In nature, animals, plants and microbes do not and 
cannot live in isolation but interact in various 
ways to form a biological community.  
 
Even in minimal communities, many interactive 
linkages exist, although all may not be readily 
apparent.  
 
Interspecific interactions arise from the interaction 
of populations of two different species.  
They could be beneficial, detrimental or neutral 
(neither harm nor benefit) to one of the species 
or both. 
 
Predation, parasitism and commensalisms 
share a common characteristic– the 
interacting species live closely together. 
 
PREDATION  
 
It is nature’s way of transferring to higher trophic levels the 
energy fixed by plants. 
Besides acting as ‘conduits’ for energy transfer across trophic 
levels, predators play other important roles.  
They keep prey populations under control. 
 But for predators, prey species could achieve very high 
population densities and cause ecosystem instability.  
When certain exotic species are introduced into a 
geographical area, they become invasive and start 
spreading fast because the invaded land does not have its 
natural predators. 
 The prickly pear cactus introduced into Australia in the early 
1920’s caused havoc by spreading rapidly into millions of 
hectares of rangeland.