Ecosystems 8.11 The student knows that interdependence occurs among living systems and the environment and that human activities can affect these systems. The student is expected to: (A) Describe producer/consumer, predator/prey, and parasite/host relationships as they occur in food webs within marine, freshwater, and terrestrial ecosystems; (B) Investigate how organisms and populations in an ecosystem depend on and may compete for biotic and abiotic factors such as quantity of light, water, range of temperatures, or soil composition

What is an ecosystem? Click here to find out! There are several different types of ecosystems including: marine, freshwater, and terrestrial.

Quick Review:What are Biotic & Abiotic Factors? Click here to find out!

Words to know… Species- group of organisms that can mate and produce offspring that in turn can produce more offspring Population- all of the organisms of the same species that live in the same place at the same time Community- areas where populations share the environment with other populations Ecosystem- all of the living and non-living factors in an area

Factors that Affect Populations Limiting factors- factors such as food, water, and living space; factors that limit how many organisms can live in one environment There is only so much food and water available in an ecosystem. Plants and other organisms that make their own food need light for photosynthesis. If light is limited, their growth is limited. Organisms need room to live, obtain resources, and reproduce. This is called a habitat. A niche is a role that an organism plays in a habitat.

Relationships Between Populations Competition occurs when more than one individual or population tries to use the same limited resources. There is not enough food, water, and space for all organisms, so only those who get the resources they need will survive. Predation is a type of feeding relationship where one animal (predator) eats another animal (prey). Symbiosis is a close relationship between two species including mutualism (both benefit), commensalism (one benefits, the other is not harmed or helped), and parasitism (one is harmed, one is helped).

COMPETITION Organisms compete for resources Competition can be intraspecific (competing with organisms of the same species) Competition can be interspecific (competing with organisms of different species) Login to you tube in order to show the video. Use this as a way to spur discussion on way animals compete to stay alive in their environment.

Click here for Competition, Predation, and Symbiosis Video Login to you tube in order to show the video..

What do organisms compete for? Plants and animals compete for the following biotic and biotic factors: Quantity of light Water Range of temperatures Soil composition They compete because there is a limited number of resources.

PREDATION Click here to see a video! A predator is an animal that kills or hunts other animals for food. What is an example of a predator in a marine ecosystem? Freshwater? Terrestrial? Prey is an animal that is eaten by another animal. Give an example of prey in a marine ecosystem. Freshwater? Terrestrial?

SYMBIOSIS Symbiosis is a close relationship between two species. There are three types: Mutualism- both species benefit Click here for a video about mutualism. Commensalism- one species benefits and the other is neither helped nor harmed Click here for a video on commensalism. Parasitism- one species benefits and the other is harmed Click here for a video about parasites.

Parasite vs. host…what’s the difference? A parasite takes nourishment from and harms the host. A host is the organism infected with or fed upon by a parasitic organism. Give an example of a parasite and host from a marine, freshwater, and terrestrial environment.