Interactions Among Living Things

A 7th Grade science presentation

Interactions

There are three major interactions among organisms:

Competition Predation Symbiosis

Predation Predation is an interaction in which one organism

kills and eats another organism. The organism that does the killing is the predator. The organism that is killed is the prey.

Predation can have a major effect on the size of a population.

Competition Competition is the

struggle between organisms to survive in a habitat with limited resources.

Symbiosis

Symbiosis is a close relationship between two species that benefits at least one of the species

There are three types of symbiotic relationships:

Mutualism Commensalism Parasitism

Mutualism

mutualism is an interaction between two or more species where both species derive benefit.

Ant-aphid mutualism: the aphids are protected from predators by the ants. The ants get the aphid secretion of honeydew as a reward.

Commensalism Commensalism—is a relationship in which one species

benefits and the other species is neither helped nor harmed. The Remora fish (Echeneidea) is a long slender fish which has its

dorsal fin modified as a sucker-like attachment organ. It attaches to the sides of larger fish and turtles using them as transport hosts but in addition, obtains food fragments dropped from the host.

An organism living on or inside

another organism and harming it. Head lice Ticks Fleas Heart worm

Parasitism

Tape Worm

Athlete’s foot

Ring worm

Parasitism

The organism that benefits is called a parasite.

The organisms that it lives on or in is called a host.

Thank you

For paying attention and taking notes. This concludes the slide show.