Negative Interactions – Interaction between two species where atleast one of the species gets harmed.
Types:
Predation (+,-):
Ø It is the relationship between the predator and the prey where the prey is food for the predator.
Ø Ex) Cheetah and deer. Cheetah hunts the deer for food.
Ø Predation is a natural process which controls the population growth of the prey without which the ecosystem won’t survive.
Parasitism (+,-):
Ø It is the interaction between two species in which one (the parasite) obtains its food from the other living organism (the host).
Ø Ex) Human and lice. The lice (parasite) feeds on the human’s blood (host) in order to survive.
Ø A typical parasite lives in its host without killing it.
Ø Animal parasites may be ecto- or endoparasites. Ectoparasites are those which lives outside of the host. Ex) ticks,mites. Endoparasites live inside the body of the host. Ex) Plasmodium (malarial parasite) in the liver and blood cells.
Ø Advantages-
o Host and parasite tend to co-evolve. If host evolves special mechanisms for resisting the parasite, the parasite evolves mechanisms to counteract and neutralize them.
o Genetic transformation takes place due to mixing up of genes as in the case of lice.
Amensalism (-,0):
Ø It is the interaction between two species in which one species is adversely affected and the other species is neither benefitted nor harmed.
Ø Ex) small plant present under the shadow of a tree. The tree would not allow sunlight to reach the ground which ultimately leads to the death of the plant.
Ø Antibiosis – amensalism through liquid secretion. Ex) algae in pond secrets toxins which harms aquatic organisms.
Competition (-,-):
Ø It is the rivalry between two individuals which require a resource that is in short supply.
Ø The competition may be for food, space or power.
Ø Intraspecific competition – it is the competition between same species. Ex) Competition between tigers for space.
Interspecific competition – competition between two different species for resources. Ex) Lions and cheetahs of the African savanna compete for the same antelope and gazelle prey.
Neutral interaction:
Ø Neither benefit nor harm to either species.
COMMUNITY
Ø It includes all population occupying a given area. Ex) Different species of animals in a forest.
ECOSYSTEM
Ø Group of organisms interacting with eachother and with physical surroundings or environment.
Ø It is the basic unit of environment.
Ø Ecosystem may be natural or man-made. Some examples of natural ecosystem includes – marshland, forest, tree etc. while man-made ecosystem refers to botanical gardens, well and apiculture.
Ø An ecosystem comprises of the producers and the consumers.
Ø Those organisms which produce food are called producers. Ex) Green plants.
Ø Those organisms which consume the food synthesized by the producers are called consumers. Ex) Animals.
BIOME
Ø It refers to a large regional or sub continental ecosystem characterized by similarity in vegetation and climate.
Ø Ex) grasslands, forests, desert, and oceans.
Content credits: Leo Karen Jerusha J
