chapter 4. 1. biotic and abiotic factors. 2. the niche 3. community interactions 4. ecological...
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1. Biotic and abiotic factors.2. The niche3. Community interactions4. Ecological succession
What Shapes an Ecosystem?
Living factors that influence an ecosystem are called biotic factors.◦ All the organisms and their interactions.
Nonliving factors that influence an ecosystem are called abiotic factors.◦ Sunlight, temperature, humidity, average rainfall,
soil composition, rock structure…
Biotic and Abiotic factors
How an organism interacts within its environment is called its niche.◦ What it eats◦ How it obtains food◦ When and how it reproduces◦ If and how it cares for its young◦ How it modifies its environment
No two species can occupy the same niche.
The Niche
Bay-Breasted WarblerFeeds in the middlepart of the tree
Yellow-Rumped WarblerFeeds in the lower part of the tree andat the bases of the middle branches
Cape May WarblerFeeds at the tips of branchesnear the top of the tree
Spruce tree
Section 4-2
Figure 4-5 Three Species of Warblers and Their Niches
Organisms interact constantly in their community and help shape the ecosystem.◦ Competition◦ Predation◦ Symbiosis
Community Interactions
Competition◦ Organisms compete for the same resources.
Water, food, shelter, mates…
Community Interactions
Symbiosis◦ Two different species live in close association with
each other and at least one benefits.
Community Interactions
Ecosystems change over time until a climax community is established. ◦ This is called ecological succession.
Ecological Succession
Primary succession◦ Occurs on surfaces where no soil exists.◦ Bare rock◦ Lichens and moss.
Ecological Succession
Secondary succession occurs when a disaster (natural or man-made) destroys an original community.◦ Ecosystems tend to return to their climax
community unless human activity prohibits this.
Secondary Succession
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