Relationships in Ecosystems

Introduction Organisms do not live on their own. Every organism is linked in some way to at least one other living thing. Plants are closely associated with herbivores which depend on all kinds of vegetation for their survival. All predators are dependent on their prey. Organisms are in constant competition with each other for space and food. A few organisms have very close associations with each other. In many cases the organisms in the association are so dependent on one another that they are unable to survive on their own. In today's lesson we are going to look at a number of different relationships between organisms. Use an online dictionary to find the definition of the word 'symbiosis'. Put this definition into your own words in the space below. Symbiosis Video Watch the following video to get an understanding of some of the different types of relationships that organisms can be in in different ecosystems. Symbiotic Relationships Match the symbiotic relationship with the definition. Symbiotic relationships Are relationships that benefit one or both of the species. Parasitism One species is benefited while the other species is harmed. Mutualism Where both species benefit. Commensalism Where one species benefits while the other is not harmed. Click on the title and read the information on predator-prey relationships. Then use the information to complete the next activity. Predator-Prey Relationships Predator-Prey 'Shake 'em Off!' Watch this short video to see how wolves and deers interact with each other as a predator-prey relationship. Using the information from the website & video provided, fill in the blanks! Word bank: predator, cactus, prey, necks, predator, prey, evolve, plants, predator, prey A predator is an organism that eats another organism. The organism that they eat is known as the prey. An example of this is the relationship between a lion and a zebra. The lion would be the predator and the zebra would be the prey. If there is no prey around to eat, the predator will die because it will not have enough food. If this happens, the predator will need to evolve whatever is necessary in order to eat the prey; speed, stealth, a change of colour, etc. Likewise, the prey will need to evolve to make sure that all of them are not eaten by the predator. To evolve means to change. When animals eat plants, this is also considered to be a predator-prey relationship. Galapogas tortoises eat the branches of cactus plants that grow on the island where they live. Some of the tortoises have different shaped necks to help them to eat the plants that are different sizes. This is known as an adaptation. Use the Internet to find a definition of the word 'adaptation'. Put this definition into your own words in the space below.