Ecological Energetics and Nutrient Cycling Flashcards
(13 cards)
What are producers?
-Organisms that manufacture organic substances from inorganic substances using energy.
-Plants are producers and some bacteria are
What do producers use to produce organic compounds?
Almost all producers (plants) use light energy to produce organic compounds by photosynthesis (photoautotrophs). A very small number of producer species (chemoautotrophs) use chemical energy rather than light to produce organic compounds from inorganic materials.
What are some examples of chemoautotrophs?
-Prokaryotes that live in deep cave systems far from available light - use the minerals in the rock as a source of chemical energy
-Nitrifying bacteria
What are consumers?
-Organisms that obtain their energy by feeding on other organisms.
-Animals are consumers
What is the order of the food chain?
-Primary consumers feed on producers (plants)
-Secondary consumers feed on primary consumers
-Tertiary consumers feed on secondary consumers
-Primary consumers are also called herbivores (plant feeders) and secondary and tertiary consumers are called carnivores as they feed on other animals.
What are decomposers and detritivores?
Groups of organisms involved in decay and decomposition.
What is a food chain and what is each stage of it referred to?
-A food chain shows the link between a producer, a primary consumer, a secondary consumer and possibly a tertiary consumer.
-Each stage is referred to as a trophic level with producers being at the first trophic level, primary consumers at the second trophic level and so on.
Why are food chains not usually a realistic representation of the feeding relationships involved in an ecosystem?
Most animals do not rely on a single food source- this would be far too risky in most ecosystems
What is a food web?
A food web is the pattern of interrelated “food chains” that operate in an ecosystem. In complex ecosystems, such as the climax community stage, food webs tend to be very complex involving many different species.
What do ecological pyramids show?
The relative number or biomass (quantitative relationships) of organisms at each trophic level of a food chain/web.
Energy of the organisms involved can also be represented.
What does a pyramid of numbers represent?
A pyramid of numbers represents the total number of organisms at each trophic level in a food chain or web.
What do pyramids of numbers look like?
-The length of the bars in a pyramid of numbers is drawn proportional to the number at each level (the depth of the bars should be the same for each level).
-Normally there will be more organisms at the producer level than there are primary consumers, and so on, this gives a pyramid shape.
-Pyramids of numbers are often a very simplified inaccurate picture of the energy flow between trophic levels. They do not take account of the size of the organism.
