LESSON TWO - The Needs of Living Things - OceanLink

Symbiosis – literally means “living together”. When two organisms interacttogether in such a way as to benefit one or both of the organisms.Predator - an organism that hunts another living thing for food.Prey - an organism that is hunted by a predator.Mutualism - a close relationship between two organisms in which both organismsbenefit (a type of symbiosis).Parasitism - a relationship between two organisms in which one is harmed and theother benefits (a type of symbiosis).Parasite - an organism that derives nutrition from a host causing harm to the hostCommensalism - a relationship in which two organisms live together; one benefitswhile the other is unaffected (a type of symbiosis).Symbiont – an organism living “symbiotically” is a symbiont.Endosymbiont - a symbiont that lives inside another organism (“endo” meaninginside).Trophosome – the organ inside some hot vent tubeworms that contain thesymbiont microbes. These “gutless worms” have trophosomes in the place ofstomachs and “plumes” instead of mouths!The key words provided are integral to this lesson plan. If the ecology terminology has not alreadybeen covered in your class, you will need to teach the material prior to this lesson.British Columbia PLO’s:• Grade 7 Life Sciences – EcosystemsBackground:1. EcologyAn ecosystem is a network of interactions that link the living and non-living parts of an environment.The living parts of the ecosystem include the organisms, such as the plants and animals that livewithin the environment. Each different type of organism is known as a species. All the members ofone particular species in a give area are called a population. When two or more populations ofdifferent species live in the same area, they form a community. The non-living parts of the ecosysteminclude elements such as sunlight, rain and snow, sediment, rock, and temperature.2. Energy Sources: Photosynthesis and ChemosynthesisAll living things need energy. People and other animals get their energy from the food they eat.However, neither the plants on land nor the microbes that live around hydrothermal vents eat food.Instead, they make their own food. Organisms that make their own food are called producers.