Option C - Ecology and conservation
Question 1
HLPaper 3Discuss how crop plants obtain the phosphorus that they need to grow and whether the supply of phosphorus to crops is sustainable.
Question 2
SLPaper 3A survey was made of the intertidal zone at Butter Lump Bay, Great Cumbrae, Scotland. The three species of barnacle found were Elminius modestus (EM), Chthamalus montagui (CM) and Semibalanus balanoides (SB). The kite diagram shows the vertical distribution of these three species from the low tide mark at 0 m to 2.25 m above low tide.
Outline how the data could have been obtained.
Describe the distribution of C. montagui and S. balanoides barnacles in Butter Lump Bay.
E. modestus is an invasive barnacle while the others are native species. Analyse the data to show how it supports this statement.
State one abiotic factor that could have determined the distribution of barnacles.
Barnacles are sensitive to pollution. Outline how it might be possible to use these organisms as indicator species.
Question 3
SLPaper 3Explain why some biologists think protecting keystone species would help preserve biological diversity in an ecosystem.
Compare and contrast fundamental and realized niche of a species.
Question 4
HLPaper 3The interaction web shows top-down and bottom-up effects in a seagrass study system.
Identify which of the types of interaction shown in the key occur between crabs and seagrass.
Describe how the sea otter indirectly affects seagrass.
Explain how nutrients can have a positive or negative bottom-up effect on seagrass.
Question 5
HLPaper 3The Vancouver Island marmot (Marmota vancouverensis) is a small rodent that is only found on Vancouver Island and is listed as critically endangered. Captive breeding and release programs for this species began in 1997 to attempt to restore population numbers on the island. The graph shows the causes of death of the marmots born in the wild and of those marmots released after being born and reared in captivity.
Distinguish between levels of predation in marmots born in the wild and those born in captivity.
Suggest reasons for the differences in predation.
Distinguish between ex situ and in situ conservation of endangered species.
Question 6
SLPaper 3After their introduction cane toads (Rhinella marina) have become a serious pest in many parts of Australia. In an attempt to control them scientists set traps to which they added toxins produced by native species of toad to capture cane toad tadpoles. The toad toxin attracts the cane toad tadpoles without killing them.
Outline one consequence of introducing an alien species into an ecosystem.
State the origin of cane toads.
Evaluate the use of traps containing toxin as a means of cane toad control.
Question 7
HLPaper 3In 1911, twenty-five reindeer (Rangifer tarandus) were introduced onto Saint Paul Island in Alaska and the population was recorded for 40 years.
State the type of growth of this population up to 1940.
Suggest one possible cause for the decrease of the number of animals after 1940.
Explain biogeographic factors that increase the effectiveness of nature reserves.
Question 8
HLPaper 3Define indicator species.
Indicator species may be affected by biomagnification. Discuss biomagnification using a named example of a pollutant.
Determine whether islands are open or closed ecosystems.
Question 9
SLPaper 3The diagram shows the copper concentration (μg g–1) in the seaweed Porphyra umbilicalis collected along the shoreline in Arklow, Ireland.
Explain how the copper found in these seaweeds could affect the birds living in Arklow town.
Question 10
HLPaper 3Define fundamental niche.
Outline a reason for organisms seldom occupying their entire fundamental niche.
Describe the relationship between Zooxanthellae and reef-building coral species.
