ecosystems Flashcards
(29 cards)
What is an ecosystem?
An ecosystem includes all the organisms living in a particular area known as the community as well as all the non-living elements of that particular environment.
What factors control the distribution and abundance of organisms in a habitat?
Both biotic (living) factors, such as predators and pathogens, and abiotic (non-living) factors, such as light levels and temperature.
What is a niche?
Each species has a particular role in its habitat called its niche, which consists of its biotic and abiotic interactions with the environment.
What is succession?
Succession is the change of one community of organisms into another.
What is primary succession?
Primary succession occurs when an area previously devoid of life is colonised by communities of organisms, such as after a volcanic eruption.
What are pioneer species?
Pioneer species, such as lichens, are the first to colonise an area in primary succession and are adapted to survive in harsh conditions.
What is a climax community?
A climax community is the final seral stage of succession, a self-sustaining and stable community of organisms.
What is secondary succession?
Secondary succession occurs in a previously colonised area where an existing community has been cleared, such as after forest fires.
What is biomass?
Biomass is the mass of carbon or dry mass of tissue per given area per given time, synthesized by plants from carbon dioxide.
What is net primary productivity (NPP)?
NPP is the rate at which energy is transferred into organic molecules that make up new plant biomass, after respiratory losses.
What is gross primary productivity (GPP)?
GPP is the rate at which energy is incorporated into organic molecules in plants during photosynthesis.
What is the formula for net primary productivity?
NPP = GPP - R, where R represents respiratory losses.
How is the net production of consumers calculated?
N = I - (F + R), where I is the energy from ingested food, F is energy lost in faeces and urine, and R is respiratory losses.
Why is nitrogen important?
Nitrogen is essential for the synthesis of proteins and nucleic acids.
How is nitrogen fixed for plant use?
Nitrogen is fixed by bacteria such as Rhizobium, which live in root nodules of leguminous plants.
What role do chemotrophic bacteria play in the nitrogen cycle?
Chemotrophic bacteria oxidise ammonium ions to nitrites, and then nitrites to nitrates.
What is the carbon cycle?
The carbon cycle recycles carbon through the environment via photosynthesis, feeding, respiration, and decomposition.
What methods are used to measure the abundance of organisms?
Methods include line transects, quadrats, and belt transects.
What are limiting factors in population sustainability?
Limiting factors include food, water, light, oxygen, nesting sites, shelter, parasites, and predators.
What is interspecific competition?
Interspecific competition is the competition between individuals of different species.
What is intraspecific competition?
Intraspecific competition is the competition between individuals of the same species.
What is the difference between conservation and preservation?
Conservation maintains or increases biodiversity through sustainable resource use, while preservation maintains biodiversity levels and habitats intact.
What are some economic reasons for conservation?
Economic reasons include the provision of food, medicine, and the importance of species for processes like pollination.
What is coppicing?
Coppicing is the cutting down of trees close to the ground to encourage new growth.
