Biology questions and solutions
Browse original practice and official past-paper questions. Each question has its own link, with its source and worked solution.
385 questions · Page 12 of 17
- Q35 · Original practice · 5 marksBiodiversity and populationsForty possums are captured, marked and released. A second capture contains 50 possums, of which 10 are marked.
- Q36 · Original practice · 5 marksBiodiversity and populationsThe graph shows the mean number of seedlings per 1 m² quadrat at locations along a dune transect. Soil salinity decreases with increasing distance from the shore.
- Q37 · Original practice · 4 marksBiodiversity and populationsFive quadrats were divided into 25 equal grid cells. The table records the number of cells occupied by a shrub in each quadrat. A cell was counted if at least half its area was covered.
- Q38 · Original practice · 4 marksBiodiversity and populationsA biologist uses the key to identify four hypothetical insect species. The specimen has unbranched antennae, spotted wings and no tail filaments.
- Q39 · Original practice · 4 marksBiodiversity and populationsThe table shows selected taxonomic information for three hypothetical beetles.
- Q40 · Original practice · 4 marksBiodiversity and populationsIn a forest, trees 16 m tall form the highest vegetation stratum. Their foliage projective cover falls from 55% to 22% after a cyclone. Shrub cover remains 80%. Use the supplied Specht excerpt.
- Q41 · Original practice · 4 marksBiodiversity and populationsAn investigator uses the supplied simplified Holdridge excerpt. A site has annual biotemperature 20 °C and a potential evapotranspiration-to-precipitation ratio of 0.70. Treat boundaries exactly as listed.
- Q42 · Original practice · 5 marksBiodiversity and populationsAn annual survey of a bird colony begins with 750 individuals. Over one year there are 140 births, 95 deaths, 32 immigrants and 47 emigrants.
- Q43 · Original practice · 5 marksBiodiversity and populationsThe two curves show population sizes in different habitats. Curve P is solid and curve Q is dashed.
- Q44 · Original practice · 5 marksBiodiversity and populationsTwo hypothetical plants have the life-history characteristics shown.
- Q45 · Original practice · 5 marksBiodiversity and populationsTwo teams independently sample equal areas of a grassland using the same quadrat size. Team A selects the five greenest patches. Team B uses 25 random locations. Their SDI estimates are 0.82 and 0.61 respectively.
- Q46 · Original practice · 7 marksFunctioning ecosystems and successionThe diagram shows an annual energy budget. All values are in . The producer input is gross primary productivity. Assume the grazer energy budget is complete.
- Q47 · Original practice · 6 marksFunctioning ecosystems and successionA sealed terrarium contains plants, small herbivores and decomposers. Its measured carbon flows are shown. Assume the table includes all transfers between atmospheric CO₂ and living organisms during this day.
- Q48 · Original practice · 6 marksFunctioning ecosystems and successionThe diagram shows selected nitrogen-cycle transformations. Letters represent biological processes.
- Q49 · Original practice · 4 marksFunctioning ecosystems and successionA water molecule enters a plant through its roots. Some of this water is later released from the leaves; some is used in photosynthesis.
- Q50 · Original practice · 5 marksFunctioning ecosystems and successionA lake has a standing biomass of 18 kg of phytoplankton and 54 kg of zooplankton at one sampling time. Over the month, new biomass production is 900 kg for phytoplankton and 90 kg for zooplankton.
- Q51 · Original practice · 5 marksFunctioning ecosystems and successionThe graph shows counts of a prey species and a predator species in a reserve. Solid and dashed lines are identified in the key.
- Q52 · Original practice · 5 marksFunctioning ecosystems and successionResearchers remove a predatory sea star from one experimental reef plot. A similar plot is left unchanged. Initial species richness is 12 in both. After one year, results are as shown.
- Q53 · Original practice · 4 marksFunctioning ecosystems and successionTwo grass species grow along a moisture gradient. When each is grown alone, both occur across the full gradient. When grown together, species P occupies wetter sites and Q occupies drier sites.
- Q54 · Original practice · 5 marksFunctioning ecosystems and successionThree relationships are observed: a tick feeds on a wallaby; a fungus supplies a plant with mineral nutrients while receiving sugars; a barnacle gains transport on a whale without a measurable effect on the whale.
- Q55 · Original practice · 5 marksFunctioning ecosystems and successionA fertiliser spill increases available nitrogen in a lake. Algal biomass rises sharply, then dissolved oxygen falls after much of the algae dies.
- Q56 · Original practice · 5 marksFunctioning ecosystems and successionA reserve supports a herbivore population. A prolonged drought begins at month 8. The table records the carrying capacity estimated from resource availability.
- Q57 · Original practice · 6 marksFunctioning ecosystems and successionSite A is a newly exposed rock surface after a glacier retreats. Site B is a burnt grassland where soil, roots and a seed bank remain.
- Q58 · Original practice · 5 marksFunctioning ecosystems and successionThe graph shows percentage cover of three plant groups after a disturbance. Cover values describe each group separately and may overlap vertically.