Chapter 18 {pages 478-495}: Interactions within Ecosystems

Organization of Life Biosphere – Earth and its atmosphere Biome – A large geographical region classified by its climate and dominant organisms Ecosystem – A community of living organisms and non-living components in an environment. Community – Multiple populations in the same environment Population – A group of the same species Organism – A single living thing Can be plant, animal, fungus, or bacteria

Habitat versus Niche Habitat – physical location within an ecosystem where an organism can live Niche – the location, role of “job” an organism plays in that habitat; how an organism responds to resources…it’s behaviors….. Organisms often share a habitat, but rarely fill the exact same niche!

niche The profession of the organism: where it works and what it does. The ecological niche of seaweed is to grow in the coral reef, absorb water, sunlight, and nutrients for photosynthesis, provide shelter and food for other organisms, and give off oxygen into the ocean.

So, how can multiple organisms share an ecosystem?

Interactions between Organisms 3 Main Categories Competition Predation Symbiosis

Food, Water, Shelter, Light, Mate, Territory Competition when two organisms of the same or different species attempt to use the same resource in the same place at the same time. Food, Water, Shelter, Light, Mate, Territory

Why Compete? Organisms that exist in the same environment have adapted to require the same types of resources. Ex/ All arctic animals have adapted to the artic environment.

Predation—one organism captures and feeds on another organism *Predator—one that does the killing *Prey—one that is the food

Interactions between Organisms Symbiosis Close and long-term interaction between two different biological species living closely together Dependency for survival NOT just about a feeding relationship 3 main types Commensalism Mutualism Parasitism

Commensalism - one member benefits and the other is neither helped nor harmed. Clown fish and Anemones – clown fish use the stinging properties of the anemones for protection

Birds build nests in trees. The Remora fish attaches to the shark and gets a free ride. Commensalism Birds build nests in trees.

Mutualism—both species benefit insects and flowers – Insect uses the flower for food, while the plant uses the insect for reproduction

Parasite lives on or inside another organism (host) and harms it. Parasitism Parasite lives on or inside another organism (host) and harms it. The parasite obtains all or part of its nutritional needs from the host. Host needs to live in order to continue acting as a food source and shelter. Fleas biting a dog.

Parasitism Wasp eggs on back of caterpillar. Sea lampreys feed on fluids of other fish. Mosquito biting a human.