Introduction to Ecosystems 2/13/12
What is a species? A group of individuals who have similar enough DNA that they are able to produce viable offspring.
What is a population? Several individuals of the same species that live in the same area.
What is a community? Populations that interact with one another.
What is an ecosystem? An ecosystem a community of biotic (living) organisms that interact with abiotic (non-living) organisms in an interdependent system.
What is a biome? A type of ecosystem that shares similar climate, and components.
What are primary producers? An Autotroph; A species that creates its own food through photosynthesis or from reduced inorganic compounds.
What are consumers? Organisms that eat other organisms to obtain energy.
What are decomposers? Organisms that obtain energy by feeding on the dead remains of other organisms or waste products. Get nutrients and live on dead organic matter (habitat)
What is are trophic levels? Trophic levels are organisms that obtain their energy from the same source. Energy moves through ecosystems in the form of light, or chemical energy. Usually no more than 4-5 trophic levels, due to 2 nd law of Thermodynamics.
What is an herbivore? An organism that eats plants.
What is an omnivore? An organism that eats plants and animals.
What is a carnivore? An organism that eats other animals.
What is a predator? An organism that kills and consumes other organisms.
What is a prey? An organism that is consumed by a predator.
What is the carrying capacity of a population? When a population stabilizes at a maximum number of individuals that can be supported by resources available in the habitat over a sustained period of time.
How does the carbon cycle relate to the food chain? Carbon (and other nutrients) move up the food chain, carrying with it stored energy.
What is parasitism? A long term relationship between two organisms that is beneficial to one organism (the parasite), but detrimental to the other (the host). (+/-) Example: Wasps that lay eggs in caterpillars, malaria causing plasmodium, misquitos, Mycobacterium (causes tuberculosis), lice, tapeworms
What is mutualism? A type of symbiotic relationship between two species that is beneficial to both species. (+/+) Examples: Bees and flowers, Treehoppers and ants, Lichen = algae+fungus
What is commensalism? A relationship in which one organism benefits and one the other neither benefits or is harmed by the interaction. (0/+) Barnacles on whales, Remora sharks hitch a ride on larger sharks, clown fish and sea anemones
What is amensalism? A relationship in which one organism is harmed and the other neither benefits or is harmed. (0/-) Penecillin kills bread mold, humans and cattle or sheep trample the grass, Black walnut trees secrete chemicals that kill other plants, redwoods have tannic acid in their leaves/needles that make the soil too acidic for other plants to grow
What is competition? A relationship in which both species are negatively affect by the outcome of the interaction. (-/-)
What is an ecological niche? A specific role or job that an individual has in an ecosystem.
What is a keystone species? A species that has an exceptionally great impact on the surrounding community. Pisaster (sea star), sea otter
Net Primary Productivity
What is photosynthesis? A series of chemical reactions and electron transfer events that converts the energy of light into chemical energy stored in glucose. Equation for photosynthesis: 6CO 2 + 6H light energy C 6 H 12 O 6 +6O 2
Why is dissolved oxygen a measure of productivity? Dissolved oxygen is produced in photosynthesis. Dissolved oxygen is consumed in cellular respiration.
What is gross primary productivity? The amount of biomass produced by photosynthesis per unit area over a specific time period.
What is Respiration? Metabolizing glucose (carbon compound) into chemical energy using oxygen.
What is Net primary productivity? The Net primary productivity= gross primary productivity - respiration