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Unit 4: Ecology. The study of the relationship between organisms and their environment. I. Ecosystem Dynamics. Ecosystem: Any community of organisms and the abiotic factors that affect it. B. A Stable Ecosystem is one where:.
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Unit 4: Ecology The study of the relationship between organisms and their environment.
I. Ecosystem Dynamics • Ecosystem: Any community of organisms and the abiotic factors that affect it.
B. A Stable Ecosystem is one where: 1. Population numbers fluctuate at a predictable rate.
2. The supply of resources in the physical environment fluctuates at a predictable rate.
3. Energy flows through the ecosystem at a fairly constant rate over time.
C.Ecosystem Interactions • Predation: The predator kills and eats the prey.
Competition: two or more organisms need the same resource at the same time. (Paramecium sp.)
Symbiotic Relationships: * Organisms live together in direct contact. • Parasitism: Parasite benefits at the expense of the host without killing the host.
Commensalism: One benefits/ other unaffected.
D: Population Density • Population: A group of one species of organism living in a particular area. • Population Density: # of organisms in a population. • Regulated by limiting factors: • Density–dependent (lg vs. sm) • Density–independent (any size) • Abiotic (chemical or physical) • Biotic (+ or – of other organisms)
Ecosystem Limiting FactorsCW: Make a table of six organisms(3 producers and 3 consumers) in this environment and their limiting factors.
E. Ecological Succession:*A sequence of bioticchanges that regenerate or create a community.* Each community creates new conditions allowing other species to colonize the area.
1. Primary Succession: *Creating a brand new community. *Begins with Pioneer Species (Lichens & Mosses)
2. Secondary Succession* Regenerates a disturbed community.* Begins with the stage not destroyed by the disturbance.
1° Succession Stages of a Deciduous Forest Ecosystem • Pioneer species stage: Lichens (Fungi & Algae Symbiotic Organism) and Mosses • Weed stage: grasses, wildflowers • Shrub stage: dogwoods, blackberry • Fast growing tree/soft woods stage: pines, birch, other small trees • Climax community/hard woods stage: Oak/Hickory or Beech/Maple
HW: • Read p. 445 – 447. • Do Section Assessment #1-5 in complete sentences or Q/A.
II. Human Impact on Ecosystems • Habitat Destruction • Introduced Species • Pollution • Population Size • Overuse
Habitat Destruction Habitat and Niche How an organism uses the biotic and abiotic factors as it lives in its habitat. All of the biotic and abiotic factors where an organism lives. ***If we destroy the habitat, we interrupt the ability for the organisms in that habitat to perform their niches.
* Coral Reef Ecosystem Organism: Coral Habitat Destruction Example* Niche Biotic factor: Plankton* Niche Abiotic factor: Sunlight** Fishing nets block both the sunlight and the ability for the coral polyps to gain access to plankton for feeding.***How would this further destroy the habitat?
Overuse Over the past 50 years, the number of large predatory fish in the oceans has dropped by a startling 90 percent. (Mark, http://www.blogger.com/profile/02927709247847802096)WHY???
