ECOSYSTEMS ‘A World of Interactions’

Populations  What is a population?  When we talk about populations what in general do we mean?  A group of organisms of the same species that live in a specific geographical area and interbreed. (Usually breed with members of their own area.)  The group in general and the size of the population, or the number of individuals in it.

Community A number of interacting populations of species form a community within an ecosystem within a specific geographical area. The total of the interactions can best be represented as a food web.

Species Interactions

How Do Species Interact With Each Other?  There are 5 main types of species interactions. They include: predation, competition, parasitism, mutualism, and commensalism.

Predation  In predation, one organism eats and kills the other organism. The organism that is eaten is called the prey, and the one that does the eating is called the predator.  Predators limit the population size of their prey. Also, they tend to feed on old and weak individuals who are more likely to die anyway.

This red-tailed hawk (predator) has captured a snake (prey) for dinner. Yum! Predation…

Competition  Competition is a relationship between species in which they attempt to use the same resource. Species can compete for: food, sunlight, territory, pollinators, mates etc…

Here, two reindeer compete for a mate. Competition…

Parasitism  Parasites are organisms that live in or on another organism without killing it right away.  The organism the parasite takes its nourishment from is known as the host. The relationship between parasite and host is called parasitism. Only one organism benefits.

The deer tick (parasite) feeds off the blood of a human (host), which can lead to the human getting lyme disease Parasitism… tch?v=rLtUk-W5Gpk

Mutualism  Mutualism is a cooperative partnership between two species. Both species benefit.

The butterfly benefits from the flowers nectar, the flower in turn benefits from having its pollen dispersed. Mutualism…

Commensalism  Commensalism is a relationship in which one species benefits and the other is neither harmed nor helped.  It is the rarest type of species interaction.

Burdock uses its ‘velcro’ to attach to animals as they pass, this helps to spread its seeds. The plant benefits (seeds are Spread) while the animal is neither helped or harmed. Commensalism…