Community Interactions: Symbiosis Predation Role a Predator Plays in the Community Keystone Species Chapter 37, Sections 1-7

Do Now: Identify the type of community interactions using the following notations. + + + - + o Mutualism Parasitism Commensalism These are all considered a type of symbiosis. The organisms of each species have an exclusive living relationship for an extended time. Can you describe an example for each? Can you name another type of interaction which occurs in the community that would have a + - relationship?

Predation: Interaction between predator and prey Predators kill and eat other organisms Broadly defined, predators include herbivorous as well as carnivorous organisms, including cows, wolves, bats, and bears Predators tend to be larger than their prey. Name the predator and the prey in the picture.

US National Park Service 1912, Congress created the US National Park Service. 1916, Congress passed the National park System Organic Act – declared that the parks were to be maintained in a manner that leaves them unimpaired for future generations and established the National Park Service (DOI). Stephen Mather was the first Director of NPS. He began establishing grand hotels and other tourist facilities in parks with spectacular scenery to encourage tourism by allowing private concessionaires to operate facilities within the parks.

Role of a Predator in the Community Yellowstone National Park – founded in 1872 3,472 square miles of land Mid 1900’s saw the wolves almost eliminated from park and the lower 48 states Hunted by park vistors Wolves How did the wolves extinction affect the ecosystem of Yellowstone National Park? Wolves of Yellowstone Video

Watch the video. Listen for the changes which happened and write them in your notebook.

What Are Keystone Species? A keystone species holds a community together, when it disappears, so does the biological community. Elimination of a keystone species dramatically alters the structure and function of a community

Knowing this food chain, Food Chain of the three organisms that are involved in a trophic cascade in Yellowstone National Park Knowing this food chain, Describe the trophic cascade which cccurred in Yellowstone National Park.

Wolves of Yellowstone Video Vocabulary Apex predator: a top-level predator with no natural predator of their own; resides at the top of a food chain. Browser: an organism that eats the shoots, leaves, and twigs of trees or shrubs; elk are browsers (and grazers). Browsing: the act of eating shoots, leaves, and twigs of trees or shrub. Cottonwood recruitment: the growth of seedlings or sprouts above the level of browsers. In other words, the trees are able to grow taller than the level at which elk and other browsers can eat them. Grazer: an organism that feeds on grass; elk are grazers (and browsers). Habitat: the home or environment of a plant, animal, or other organism. Keystone species: a species that has a disproportionately large effect on its environment compared to its relative abundance. When a keystone species is removed from a system, the ecosystem may change drastically, even if the species removed was a small part of the entire ecosystem. Trophic cascade: a trophic cascade occurs when the impact of a predator on its prey affects one or more feeding or trophic level. Predators control the populations of their prey and thus indirectly benefit and increase the abundance of their prey’s prey. When the apex predator is removed, the lack of population control at the next trophic level down can affect the populations at the trophic level below. Trophic cascades must occur across a minimum of three trophic levels (e.g. secondary consumer, primary consumer, and producer). Trophic cascades can also happen from the bottom up; for example

Why Should We Protect keystone Species? They play critical roles in the cross pollination of angiosperms (bees, hummingbirds, bats). Top predator keystone species help regulate the population numbers of other species. The loss of keystone species can lead to population crashes and extinctions of other species that depend on it for ecological services.

E.O. Wilson “The loss of a keystone species is like a drill accidentally striking a power line. It causes lights to go out all over”

Aldo Leopold “We abuse land because we regard it as a commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect”