B17 - Organising an Ecosystem Flashcards
What is biomass?
The amount of biological material in an organism
What is the carbon cycle?
The cycling of carbon through the biotic and abiotic components of an ecosystem
What are decomposers?
Microorganisms that break down dead or undigested organic material. They are important in nutrient cycling
What is a primary consumer?
Animals that eat producers
What is a producer?
Organisms that produce organic molecules from simple inorganic materials and use them as an energy source. Examples include green plants and algae
What is a secondary consumer?
Animals that eat the primary consumer
What does the arrow in a food chain represent?
The direction of energy flow
What are the first 4 stages of a food chain?
Producer -> Primary Consumer -> Secondary Consumer -> Tertiary Consumer
1st Trophic Level -> 2nd Trophic Level -> 3rd Trophic Level -> 4th Trophic Level
Why are food chains limited to 4 / 5 trophic levels?
Poor energy efficiency means food chains are limited in size as little energy is passed between stages.
What are examples of producers?
Green plants and algae
What are the advantages of being a herbivore?
The food does not move, it cannot escape instead it stays still
What are the disadvantages of being a herbivore?
Cellulose is very difficult to break down and digest. Herbivores must use a variety of techniques to break down and access the cell contents. They must also eat a lot of plant mass to find and eat enough plant material to provide them with the nutrients they need
What are the advantages of being a carnivore?
Food is high in protein and fat and relatively easy to digest
What are the disadvantages of being a carnivore?
Food is in the form of other animals, therefore the food must be caught before it can be eaten
What are prey?
Consumers which are eaten
Describe how the populations of predators and prey in a community change over time?
The numbers of predators and prey rise and fall in cycles
Explain this predator prey graph:
- If there is a plentiful supply of food available (possibly due to a warm summer with lots of rain), the prey animal grow and reproduce successfully, and more offspring survive, so population increases
- As prey number increases, there is a plentiful supply of food available for the predators, so predators can reproduce successfully, and more offspring survive, so predator population increases
- The high number of predators eat a large proportion of the prey animals, so the population of the prey falls
- With fewer prey animals, there is less food for the predators, so the predator population falls as fewer offspring survive
- Due to a reduction of the population of predators, and the good food supply that results from fewer animals, prey population increases as more offspring survive.
- The cycle then repeats itself
In what circumstances is this graph true?
In a stable community - if a change occurred within the community (e.g. a drought) or a new predator arrived, then predator prey cycles would begin to change
What adds new biomass into an ecosystem?
Photosynthesis
What are 2 examples of decomposers?
Bacteria and Fungi
Explain the recycling of materials in an ecosystem (decay cycle)
Producers are eaten by consumers. The excretion from the consumers and the bodies of the consumers when they die are broken down by decomposers which digest both the dead animals, plants and waste. They use some nutrients to grow and reproduce but release carbon dioxide, water, and mineral ions as waste products. This returns mineral ions to the soil and carbon to the atmosphere. The mineral ions can then be taken up through plant roots and carbon dioxide into producers during photosynthesis.
Explain the water cycle:
- The sun heats the earths surface causing water to evaporate from lakes, rivers, and the sea. This forms warm moist air. Water is also released back into the atmosphere through transpiration and respiration in animals
- As moist air rises it cools, condensing back into a liquid and forming clouds
- The water droplets are then precipitated back to earth as snow, rain, or hail
- Surface run off and percolation return water to bodies of water and plants
What is percolation?
The movement of water through gaps in soils and rocks
How is water released in animals?
- Respiration
- Decay
- Urine
- Faeces
- Sweat