Ecosystems 10 Flashcards
What is an ecosystem?
An environment that includes all of the organisms living in a particular area
What is a community?
All the populations of all the different species of organisms living in a habitat at any one time
What are the four sizes of ecosystems?
-Biosphere
-Biome
-Habitat
-Microhabitat
What is meant by an animals trophic level?
An animals feeding relationship with other organisms or its position in a food chain
What are the five trophic levels?
-Producers
-Primary consumers
-Secondary consumers
-Teritary consumers
-Decomposers
What is a pyramid of numbers?
Shows the number of organisms at each trophic level
What is one advantage of using pyramid of numbers?
Easiest to measure
What is one disadvantage of using pyramids of numbers?
Can be distorted by large organisms
What does a pyramid of biomass show?
The combined mass of all the organisms in a particular habitat
What is an advantage of using a pyramid of biomass?
More accurate and realistic model of trophic levels
What is a disadvantage of using pyramid of biomass?
Dry mass has to be used and this involves destroying the material
Why can’t we use wet mass to measure biomass?
Wet mass is inaccurate as it is affected by water uptake, drinking and defaecating
What does a pyramid of energy show?
Represents the total energy store of the organisms at each level
What is an advantage of using pyramids of energy?
It is the most accurate way to represent a food chain
What is a disadvantage of using pyramids of energy?
It is extremely difficult to measure and uses an outdated model of energy
How can we quantify how productive an ecosystem is?
By using Net primary productivity and Gross primary productivity
What does productivity of an ecosystem depend on?
How favourable abiotic and biotic factors are
What is Gross primary productivity (GPP)?
Total energy resulting from photosynthesis or rate at which light from the sun catalyses production of new plant material
What is the formula for Net primary productivity (NPP)?
GPP - R (respiration)
What does NPP take into account?
The energy lost during respiration
What is one limitation of efficiency calculations?
You have to measure: number of abundant species, amount of organisms and body mass
Making it difficult to measure
What is the definition of succession?
The change in an ecological community over time
What is a plagioclimax community?
A final community due to human intervention
What is a climatic climax community?
The only climax community possible in a given climax
