Unit 10- Ecosystems, Food Chains and carbon cycle Flashcards
Ecosystem definition
- a self contained environment including living and non living factors
Habitat definition:
The place where an organism lives eg a pond
Population definition:
A group of organisms of the same species that breed together in the same habitat
Community definition
A group of populations of different species interacting in the same habitat
Niche definition
The role of an organism in a community, it includes everything with which the organism interacts
What is an autotroph
An organism that manufactures its own food
What is a heterotroph?
An organism that obtains its energy and mass from other organisms
The jackal occupies 2 trophies levels and a secondary and tertiary consumer, give 2 factors that could be a part of the niche of Jackals
Time at which it feeds and predators feeding on the jackal
What is GPP?
- gross primary productivity
- the rate at which plants fix light into biomass (kJm^-2year^-1)
What is NPP
- net primary productivity
- the rate at which energy is passed to the primary consumers (GPP-respiration)
How is energy lost in each tropic level?
- Transfer of energy to the surroundings in respiration
- inedible parts lost to organisms are broken down by decomposers
How is carbon released into the environment?
- respiration
- combustion
- decomposers
- Weathering of carbon rocks
What is a carbon neutral cell ecosystem?
One where carbon fixation and carbon release are balanced over long term
What is saprobiotic nutrition?
- secreting extracellular enzymes into dead organic matter surrounding to break down and absorb the soluble products
What is a carbon source?
An ecosystem that releases more carbon as carbon dioxide than it accumulates
What is carbon neutral ecosystem?
Carbon fixation and carbon release are balanced
When may a carbon sink ecosystem arise? And what product is made from them over millions of years
When conditions are not suitable for decomposers (anaerobic conditions but photosynthesis can still occur to fix the carbon)
Fossil fuels
What are the 2 types of decomposers?
Saprobionts and detritivores
How do saprobionts decompose organic substances?
Saprobionts (bacteria or fungi) use saprbiotic nutrition, ingesting their food via secreting digestive extracellular enzymes and absorbing the products
What are detritivores and how do they decay organic matter?
- small invertebrates like woodlice
- via holozoic nutrition, ingesting the food into their gut, absorbing the soluble products and egesting the insoluble waste
How do detritivores and saprobionts help each other and speed up decomposition.
- detritivores physically break up large plant tissue, any waste is egested but with a much larger surface area, for saprobionts
- detritivores aerate the soil so saprobionts respire aerobically
- detritivores excrete urea which saprobionts can metabolise
