Biology U3 T2 - Ecosystem Dynamics Flashcards
Biomass is…
the total dry mass of all living matter in an area
Explain the transfer from sunlight to biomass
Solar energy is converted into chemical energy through photosynthesis. Heat and energy is lost as assimilation occurs between the producers, consumers, and decomposers.
What is a food chain, food web, and food pyramid?
A food chain is a linear network
A food web is an interconnected representation
A food pyramid shows the ecological hierarchy
Primary productivity is…
the rate at which photosynthetic organisms (producers) produce organic compounds
Gross primary productivity is…
the entire production of organic compounds in an ecosystem from photosynthetic organisms
Net primary productivity is…
the remaining organic materials after photosynthetic organisms have fulfilled energy needs. This is the amount of organic matter available to herbivores
How to calculate percentage efficiency?
(amount of energy received in level)/(amount of energy in previous level) x 100
What are the transfers and transformations in the water cycle?
Evaporation (transformation)
Condensation (transformation)
Precipitation (transfer)
Transportation (transfer)
What are the transfers and transformations in the carbon cycle?
Photosynthesis (transformation)
Cellular respiration (transformation)
Decomposition (transformation)
Combustion (transformation)
What are the transfers and transformations in the nitrogen cycle?
Nitrogen fixation (transformation)
Ammonification (transformation)
Nitrification (transformation)
Denitrification (transformation)
An ecological niche is…
how and where an organism lives and interacts with other organisms and the abiotic environment. This includes structural, behavioural and physiological adaptations
Competitive exclusion is…
the principle that two species with identical niches cannot coexist indefinitely
A keystone species is…
a species that is critical for the survival of the ecosystem (apex predators, ecosystem engineers, mutualists)
What would happen if a keystone species were to be removed from the ecosystem?
Removing a keystone species from the ecosystem would result in other species not being able to fulfil their niche and the ecosystem undergoing radical change
Carrying capacity is…
the size of the population that can be supported indefinitely on the available resources and services of that ecosystem
Limiting factors are…
necessary resources that are present in small quantities
* Density-dependent
o Determined by size of population
o Species interactions, disease
* Density-independent
o Will affect population regardless of size
o Natural disasters, weather, pollutions, food availability
What is the formula for population growth?
Population growth rate = (birth + immigration) – (death + emigration)
What is the Lincoln Index formula?
Estimated population = (tagged in sample 1 x caught in sample 2)/(number in sample 2 already tagged)
How do limiting factors affect carrying capacity?
Limiting factors prevent a population from exceeding carrying capacity
Ecological succession is…
the gradual evolution of an ecosystem
A sere is…
a community with recognisable characteristics
A pioneer community…
includes pioneer species
A climax community is…
stable and self-perpetuating
Primary succession
the initial development in plant communities and changes over time
Secondary succession
occurs in an area that was vegetated but has been disturbed, faster than primary succession
What is a pioneer species?
First species to colonise an area. Lacks competition, can fixate nitrogen, tolerant of extreme conditions, photosynthetic, r-strategists
Temporal and spatial succession
Temporal - changes over a period of time
Spatial - changes in an area
How does human activity impact the ecosystem?
humans change land usage and overexploit resources
