Topic 4 - Biodiversity within a community Flashcards
Student concluded that species richness in mown area increased. Are they correct?
- no - dec or same no. of species
- yes - more species
How could a student use data from their sample to estimate the total no. of a species in the whole meadow?
- determine area they sampled
- calculate the total area of the meadow divided by the sample area
- multiply this figure by the no. of the species in the sample
Why is it more useful to calculate an index of diversity than to record species richness?
- index of diversity measures the pop size of each species
- so useful because may be many or little of certain species
Why might there be differences in the no. of certain species at different sites in habitat?
- less food at particular site
- so more of species starve
Give one way sampling procedure could be standardised when counting live animals?
- same sampling time
What data is needed to calculate index of diversity?
- no. of species
- no. of individuals in each species
Give two ways to ensure the index of diversity is representative of each habitat.
- large no. of samples (at least 20%)
- randomly sample to eliminate bias
Why might larger fields dec biodiversity?
- does hedge have biggest index of diversity?
What might an advantage of a farmer replanting hedges on farmland be?
- inc pollinators so inc yield of crops
What might a disadvantage of a farmer replanting hedges on farmland be?
- lose space of land
- inc pests
What is meant by ‘species richness’?
- the no. of diff species in a community
Evaluate the evidence in the graph to suggest which habitat is most advantageous for the species?
- which habitat has highest mean species richness?
- does it have the highest no. of individuals from a species throughout the year?
- is the species richness highest or lowest all throughout year?
When collecting species what’s one precaution the scientists had taken into account to make sure their method was:
- ethical
- allowed them to accurately identify the species to which each organism belonged
- species remained uninjured and were released after
- tags attached to species so they can be identified
Suggest two ways scientists could improve method for data collection of no. of species in diff areas?
- collect species at same time of year in diff areas
- collect them from more sites
Definition of species:
a group of organisms that new evoke to reproduce to produce fertile offspring
Definition of species richness:
the no. of diff species in a community
Why might it not be possible to determine if a particular sample had a greater index of diversity than another?
- no. of individuals in each species not known
- if many results from same sample area could be of same species
- other samples may have more individuals of each species
Outline a method scientists could use to determine the plant species richness at a site
- use random no. generator + coordinates to sample sites randomly
- use quadrants
- identify plant species in each quadrat
Evaluate whether data suggests if there was any significant changes in __ communities on these islands over time.
- did species richness inc or dec on each island
- was the change in diversity significant
- was it due to chance (use probabilties)
Why might the index of diversity be higher in a hedge than a barley field?
- more plant species
- more sources of food
- more habitats and niches
Grassy strips can be left around fields. They have a variety of plant species.
Why do grassy strips inc biodiversity of animals? (2 reasons)
- inc no. of habitats
- inc plant diversity = more types of food sources
Scientists decided to collect animals from soil for 40 mins.
Suggest how they decided 40 minutes was an appropriate time?
- repeat soil sorting for diff times
- collect no. of species found
- find optimum time
Do you agree with conclusion that ___ had little effect on the diversity of animals in ___ area.
- did SDs overlap when did 2 x SD refer to probabilities
- was there a diff in named species per m2 (multiple examples)
Evaluate what you could conclude from seen data about the effects of human activities on biodiversity?
- which 2xSDs overlap
- was the no. of biodiversity abt the same?
