4-2 What Shapes an Ecosystem? Photo Credit: ©Michael Fogden/DRK PHOTO Copyright Pearson Prentice Hall

Biotic and Abiotic Factors Ecosystems are influenced by a combination of biological and physical factors. Biotic – biological factors Copyright Pearson Prentice Hall

Biotic and Abiotic Factors Physical, or nonliving, factors that shape ecosystems are called abiotic factors. Abiotic factors include: temperature precipitation humidity wind nutrient availability soil type sunlight Copyright Pearson Prentice Hall

Biotic and Abiotic Factors How do biotic and abiotic factors influence an ecosystem? Copyright Pearson Prentice Hall

Biotic and Abiotic Factors The area where an organism lives is called its habitat. A habitat includes both biotic and abiotic factors. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall The Niche The Niche A niche is the full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions. No two species can share the same niche in the same habitat Copyright Pearson Prentice Hall

Community Interactions What interactions occur within communities? Copyright Pearson Prentice Hall

Community Interactions Competition Competition occurs when organisms of the same or different species attempt to use an ecological resource in the same place at the same time. A resource is any necessity of life, such as water, nutrients, light, food, or space. Copyright Pearson Prentice Hall

Community Interactions Direct competition in nature often results in a winner and a loser—with the losing organism failing to survive. The competitive exclusion principle states that no two species can occupy the same niche in the same habitat at the same time. Copyright Pearson Prentice Hall

Community Interactions The distribution of these warblers avoids direct competition, because each species feeds in a different part of the tree. 18 12 Feeding height (m) Cape May Warbler Each of these warbler species has a different niche in its spruce tree habitat. By feeding in different areas of the tree, the birds avoid competing with one another for food. Bay-Breasted Warbler 6 Yellow-Rumped Warbler Copyright Pearson Prentice Hall

Community Interactions Predation An interaction in which one organism captures and feeds on another organism is called predation. The organism that does the killing and eating is called the predator, and the food organism is the prey. Copyright Pearson Prentice Hall

Community Interactions Symbiosis Any relationship in which two species live closely together is called symbiosis. Symbiotic relationships include: mutualism commensalism parasitism Copyright Pearson Prentice Hall

Community Interactions Mutualism: both species benefit from the relationship. Commensalism: one member of the association benefits and the other is neither helped nor harmed. Parasitism: one organism lives on or inside another organism and harms it. Copyright Pearson Prentice Hall

Symbiotic relationships The otters help the kelp by eating the sea urchins which endanger it. The kelp provides and anchor for the otters while they sleep. Copyright Pearson Prentice Hall

Symbiotic relationships Lichen is really two organisms: algae and fungus. The fungus needs food but cannot make it. The algae makes food but needs some way to keep moist. The fungus forms a crust around the algae which holds in moisture. Both organisms benefit. Copyright Pearson Prentice Hall

Symbiotic relationships The tree-pies help the chital by stripping the dead velvet from the antlers. This provides them with nourishment. Therefore both species are benefiting from this symbiotic behavior. Copyright Pearson Prentice Hall

Symbiotic relationships The cleaner fish eats parasites and food bits out of the inside of this moray eel. It gets a meal and is protected from predators by the fierce eel. Copyright Pearson Prentice Hall

Symbiotic relationships Each type of Yucca plant can only be pollinated by a specific kind of Yucca moth. That moth can only live on that kind of Yucca. Copyright Pearson Prentice Hall

Symbiotic relationships Barnacles need a place to anchor. They must wait for food to come their way. Some barnacles hitch a ride on unsuspecting whales who deliver them to a food source. This does not effect the whale in any way. Copyright Pearson Prentice Hall

Symbiotic relationships The oak gall wasp stings the oak tree. The tree then grows a GALL which is a nest for the wasp’s babies. When the larva hatch, they eat their way out of the gall. Does not help or hurt the oak tree Copyright Pearson Prentice Hall

Symbiotic relationships Bedbugs are small, nocturnal parasites that come out of hiding at night to feed on unsuspecting humans. They feed exclusively on blood! Their bites often result in an allergic reaction. Copyright Pearson Prentice Hall

Symbiotic relationships The definitive host of the cucumber tapeworm is a dog or a cat (occasionally a human). Fleas and lice are the intermediate host. the dog or cat becomes contaminated when the eggs are passed in the feces, and the flea or louse ingests the eggs. The dog or cat (or human) is infected when they ingest a flea or louse. Hence the importance of controlling fleas on your pet! Copyright Pearson Prentice Hall

Ecological Succession What is ecological succession? Copyright Pearson Prentice Hall

Ecological Succession occurs following a disturbance in an ecosystem and can affect population size. It series of predictable changes that occurs in a community over time. Succession regenerates or creates a community after a disturbance. a sequence of biotic changes (competition, disease) or abiotic changes (catastrophic events/natural disasters) damaged communities are regenerated new communities arise in previously uninhabited areas

Ecological Succession Primary Succession On land, succession that occurs on surfaces where no soil exists is called primary succession. For example, primary succession occurs on rock surfaces formed after volcanoes erupt. The first species to populate the area are called pioneer species. Copyright Pearson Prentice Hall

Ecological Succession Primary succession is the establishment of an ecosystem in an area that was previously uninhabited. In this example, a volcanic eruption has destroyed the previous ecosystem. Barren rock 0-15 years. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash. Copyright Pearson Prentice Hall

Ecological Succession The first organisms to appear are lichens and mosses, 15-80 years. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash. Copyright Pearson Prentice Hall

Ecological Succession Grasses take root in the thin layer of soil, followed by low-lying plants, 80-115 years. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash. Copyright Pearson Prentice Hall

Ecological Succession Eventually, shrubs and tree seedlings sprout among the plant community, 115-200 years. Primary succession occurs on newly exposed surfaces, such as this newly deposited volcanic rock and ash. Copyright Pearson Prentice Hall

Primary succession — started by pioneer species Ex: Glacier, New Island Key here: soil needs to be created so the process is much longer

Ecological Succession Secondary Succession Components of an ecosystem can be changed by natural events, such as fires. When the disturbance is over, community interactions tend to restore the ecosystem to its original condition through secondary succession.  Copyright Pearson Prentice Hall

Secondary succession — started by remaining species Ex: Forest fire, flood, earthquake Key here: soil is already present; surviving species colonize and have to start over; process is not as long

Copyright Pearson Prentice Hall Small annual plants and lichens/mosses, 0-2 years Perrenial herbs and grasses, 2-18 years Grasses, shrubs, sun tolerant trees, 18-70 years Shade tolerant trees, 70-100 years Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 4-2 Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 4-2 Which of the following is a biotic factor in a bullfrog's niche? water a heron climate day length Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 4-2 An organism’s niche is different from its habitat because The niche does not include the place where the organism lives. the niche includes all the conditions under which the organism lives. the niche includes only abiotic factors. the niche includes only biotic factors. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 4-2 The attempt by organisms of the same or different species to use a resource at the same time in the same place is called competition. predation. symbiosis. cooperation. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 4-2 An association between two species in which one species benefits and the other is neither helped nor harmed is called symbiosis. mutualism. commensalism. parasitism. Copyright Pearson Prentice Hall

Copyright Pearson Prentice Hall 4-2 When a volcano erupts and completely destroys an ecosystem, the first species to populate the area are usually grasses and shrubs. pioneers such as lichens. small plants such as mosses. small animals such as rodents. Copyright Pearson Prentice Hall

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