Interactions Among Living Things A 7 th Grade science presentation

Interactions  There are three major interactions among organisms:  Competition  Predation  Symbiosis

Predation PPredation is an interaction in which one organism kills and eats another organism. TThe organism that does the killing is the predator. TThe organism that is killed is the prey. PPredation can have a major effect on the size of a population.

Competition C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 mmutualism is an interaction between two or more species where both species derive benefit. A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.