4.1 Species, communities and ecosystems Flashcards
Define the term species.
A group of organisms that can interbreed and produce fertile, viable offspring.
Define the term population.
A group of organisms of the same species, living in the same area at the same time.
Define the term community.
A group of different populations living together and interacting in a given area.
Define the term habitat.
The environment in which a species lives / the normal location of an organism.
Define the term ecosystem.
A community and it’s environment (including all biotic and abiotic factors).
How do autotrophs obtain their organic molecules?
They synthesize organic molecules from inorganic nutrients within the environment, using energy from: Light (photoautotrophs) Oxidation reactions (chemoautotrophs)
How do heterotrophs obtain their organic molecules?
From other organisms through a variety of feeding methods and food sources.
What are the 3 types of heterotroph and what do they do?
Consumers - ingest other living organisms.
Detritivores - ingest detritus.
Saprotrophs - externally digest dead organisms
What is another name for autotrophs?
Producers.
What is the role of autotrophs in the nutrient cycle?
They convert inorganic nutrients into organic molecules.
What is the role of heterotrophs in the nutrient cycle?
They ingest organic molecules and may release organic byproducts.
What is the role of saprotrophs in the nutrient cycle?
They break down the nutrients in dead organisms and return them to the soil.
What are three conditions sustainable ecosystems have?
Energy availability
Nutrient availability
Waste recycling
Define the term mesocosm.
An enclosed environment with a controlled condition.
Name two positive species associations.
Predator / prey relationships
Symbiotic interaction
Name one negative species associations.
Competition.
Through what sampling can the prescence of a species in a given area be determined?
Through quadrat sampling.
Summarize the quadrat sampling process into 3 steps.
- A rectangular/square frame is placed in an area, using random sampling.
- The species numbers within the frame are counted.
- The sampling process is repeated many times to gain a representative data set.
Define positive association.
If two species are typically found within the same habitat.
Define negative association.
If two species tend to not occur within the same habitat.
What is quadrat sampling most effective for counting?
Plants and sessile animals.
Name the 5 steps for creating a chi-squared test.
- Identify hypotheses (null versus alternative)
- Construct a table of frequencies (observed versus expected)
- Apply the chi-squared formula
- Determine the degree of freedom (df)
- Identify the p value (should be <0.05)
What do detritivores do? Name two examples as well.
They ingest non-living organic matter. Eg. earthworms and woodlice
What do saprotrophs do? Name two examples as well.
They feed on non-living organic matter by secreting digestive enzymes and absorbing the products.
Define photoautotroph.
An autotroph which makes organic compounds derived from the sun (solar energy)
Define chemoautotroph.
An autotroph that makes organic compounds using energy derived from the oxidation of chemicals.
