- Population: the group of individuals of a species inhabiting a given area.
- Habitat: it is the place where the organism lives. It is never occupied by a single species. It is occupied by a biological community.
- Biological community: Populations of animals, plants, and microbes living in an area and interacting with each other.
- Ecological niche: each species has a functional role to play in the ecological system.
Interdependence between species is for food, space, reproduction & protection. Interactions are important for the survival of individuals and community as a group.Interspecific interactions are between populations of two different species in a community.They can be beneficial, detrimental or neutral to one or both the species.
Population Interactions are:
- MUTUALISM –two species which stay together & both benefit, but it is obligatory.
- COMPETITION – an interaction between two individuals of same or different species for the same resource, both lose.
- PARASITISM – one species lives upon or within the other species. Parasite benefits while the host lose.
- PREDATION –one species kills & eats up the other species. Predator benefits while the prey lose.
- COMMENSALISM – two species staying together in which one benefits & the other is neither harmed nor benefitted.
- AMENSALISM – one species inhibits the growth of the other species. One is harmed & the other is not affected.
- PROTOCOOPERATION – two species which stay together & both benefit, but it is not obligatory.