Relationships in Communities

Sun – source of energy that fuels most life on Earth.

Producers - AUTOTROPHS – organisms that use an outside energy source to make energy- rich molecules. – Most producers use the Sun and contain chlorophyll, a chemical required for photosynthesis. WaterCarbon DioxideSugarOxygen ++ H 2 OCO 2 C 6 H 12 O 6 O 2 Producers

– Some producers, found near volcanic vents on the ocean floor, use mineral molecules as energy source for chemosynthesis (using chemicals to make food). Producers

Consumers - HETEROTROPHS – organisms that cannot make their own energy-rich molecules; they obtain energy by eating other organisms. – There are three types of consumers… Consumers

– Herbivores, such as deer and rabbits eat plants. Most herbivores have flat teeth for grinding plant materials. Herbivores

– Carnivores, such as frogs and lions, eat animals. Most carnivores sharp teeth or beaks for tearing meat. Carnivores

– Omnivores, such as pigs and humans, eat both plants and animals. Most omnivores have both flat and sharp teeth. Omnivores

– Decomposers, such as earthworms and bacteria, eat dead organisms. Decomposers

- Organisms in an ecosystem are constantly interacting in different ways. - Predation occurs when one organism (the predator) captures and eats another (the prey). Predation

Predator and Prey – Predator – consumer that captures and eats other consumers. – Prey – the organism that is eaten. – Predators limit the size of prey populations, increasing the number of different species that can live in an ecosystem. Predation

Besides predation, there are other close relationships in the ecosystem between species. We call this symbiosis. Symbiosis

Mutualism – a symbiotic relationship in which both species benefit. Symbiosis

Commensalism – a symbiotic relationship in which one organism benefits and the other is not affected. Commensalism The sea anemone protects the clownfish from predators. The clownfish benefits, but the sea anemone is not helped or hurt. Symbiosis

Parasitism – a symbiotic relationship in which one organism benefits and the other is harmed. Parasitism Some roundworms are parasites that rob nutrients from their hosts. Symbiosis

Cooperative actions improve a species’ survival. – Example: one deer warns the others of predators in the area. – Example: individual ants perform different tasks required for the survival of all. Cooperative Actions

BEING A PREDATOR IS NOT BAD. HEALTHY ECOSYSTEMS NEED PREDATORS!!!

Energy in Communities

A food chain is a model that shows the feeding relationships among the organisms in an ecosystem. A simple way of showing how matter and energy pass from one organism to another. Food Chain

– Food Web – Shows all the possible feeding relationships among organisms in a community. (Various Levels) Food Web

Comparing Food Chains & Food Webs

Why do animals eat? They need to get their energy from somewhere. Energy stored in the molecules of one organism is transferred to the organisms that eat it. Energy

Energy pyramids show how much energy is available within each trophic level. Energy

Biomass pyramids show the biomass, or total amount of living tissue, within each trophic level. A pyramid shows the relative number of individual organisms at each trophic level. Energy

Energy comes from the sun, but not all organisms can retain that energy. Energy (kcal) is lost when you go up each level in the food chain. Only 10% of the energy is transferred to the next level. Energy