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Bell Ringer. Bell Ringer. Can a food web or food chain ever show abiotic factors? A food web shows life at the [population, community, ecosystem] level. (Pick one.) Can an energy pyramid ever be inverted? How much energy passes from one trophic level to the next?
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Bell Ringer • Can a food web or food chain ever show abiotic factors? • A food web shows life at the [population, community, ecosystem] level. (Pick one.) • Can an energy pyramid ever be inverted? • How much energy passes from one trophic level to the next? • Can a biomass pyramid ever be inverted?
What Shapes an Ecosystem? So, how do all those organisms live together?
What shapes an Ecosystem? • Ecosystems are defined by the interactions among the biotic and abiotic factors that exist within. • The two major factors that these interactions influence are: • How organisms survive and thrive. • The overall productivity of the ecosystem.
What shapes an Ecosystem? • The area where an organism lives is called its habitat. An organism’s habitat can also include a host body, in the case of parasites. • The “role” that an organism plays in its habitat is called a niche. An organism’s niche includes: • The conditions in which an organism lives. • The means by which an organism survives.
What shapes an Ecosystem? • For example, a bullfrog’s habitat would be a pond, lake or stream, as well as the land nearby. • A bullfrog’s niche would be: • The food it eats, and is eaten by. • The cold, watery environment it lives in. • The means by which it maintains body temp. • The means by which it reproduces.
Community Interactions • Organisms that live within the same ecosystem interact with each other on a constant basis. • These interactions may or may not be beneficial, to either party.
Community Interactions • Competition: This interaction occurs when two organisms fight over the use of one resource at the same time. • The organisms may OR may not be of the same species!
Community Interactions • The competitive exclusion principle states that no two species can occupy the same niche in the same habitat at the same time. • This principle means that different species will go out of their way to avoid competing with one another. • This is because competition might lead to death for the loser!
Community Interactions • Predation: An interaction in which one organism ACTIVELY hunts and eats another. • Both predator and prey evolve adaptations to help them survive.
Community Interactions • Symbiosis: ANY relationship where two organisms live closely together. • This means the two organisms are NOT trying to kill each other… • Although there may still be negative effects!
Community Interactions • There are three possible symbiotic relationships: • Mutualism, where both organisms benefit. • Commensalism, where one organism benefits, and the other is unaffected. • Parasitism, where one organism benefits, and the other is harmed.
Exit Ticket • The role that an organism plays in its environment is its _______. • Can two different species occupy the same ecological niche? Why or why not? • Two male deer are butting heads over territory. What is this an example of? • Barnacles attach themselves to a whale to move around, and the whale is neither helped or harmed. What is this an example of?
Ecological Succession • Ecosystems do NOT stay constant over time. They will change in response to both abrupt and gradual changes in the environment. • As an ecosystem changes, older inhabitants die out, and new ones replace them. This causes the local community to continually evolve. • We call this process ecological succession.
Ecological Succession • The type of succession that occurs depends on whether soil already exists or not. • If NO soil exists, primary succession occurs. • This happens right after a volcanic eruption, or after glaciers melt. • If soil already exists, secondary succession occurs. • This happens when farmland is abandoned, or after a wildfire.
Ecological Succession • In primary succession, there is no soil to start; just ash and rock. • First, pioneer species (often lichens) populate the area. They break up the rocks to form soil. • These species die, which provides nutrients to the soil. They are eventually replaced with new plants.
Ecological Succession • In secondary succession, good soil already exists. Only the wildlife is replaced. • First, small shrubs and grasses appear. • Small bushes and evergreen trees develop first. • Eventually, the evergreens are overtaken by larger deciduous trees.
Ecological Succession • Marine ecosystems are also prone to ecological succession. • This can take the form of tectonic upheaval, of temperature changes, or of the addition of new communities or habitats.
Exit Ticket • A dog is infested with fleas, which feed of the skin and blood of the dog. What is this an example of? • What type of succession will occur after: • a wildfire? • a glacier melts? • a swarm of locusts eats most of the vegetation?
Exit Ticket • Answer true or false to all statements. • Competition only occurs between members of the same species. • Symbiosis includes mutualism, commensalism and parasitism. • Ants move aphids to new leaves, while aphids produce food the ants like. This is an example of mutualism. • The appearance of pioneer species is the first step of primary succession. • Secondary succession only occurs when there is no soil.
