19.3. Ecosystems and biodiversity
A subsection of Biology, 5090, through 19. Relationships of organisms with one another and with the environment
Listing 10 of 23 questions
Three different populations in a small lake are linked in a food chain. shows the changes in size of these populations over a period of time. Using the information in , identify the producer; name the trophic level in the food chain of organisms A. Suggest what may have entered the lake at time B and, by referring only to the plant population, explain your answer. what entered the lake: explanation size of population bacteria plants organisms A B C time [T Explain how the change in the size of the population of bacteria after time C is related to the size of the plant population. is a graph that shows the amount of oxygen in the same lake before time B. Complete the graph to show how the oxygen concentration will change over the same time period shown in . concentration of dissolved oxygen in the water B C time
5090_s05_qp_2
THEORY
2005
Paper 2, Variant 0
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The number of individuals in a population can vary with time. Table 8.1 shows how the global populations of humans and tigers are estimated to have changed between 1970 and 2000. Table 8.1 year estimated global population humans tigers 3.6 billion 35 000 6.0 billion 5 000 Suggest factors that may be causing these changes in the two populations and how the changes may be linked. In 2010 the population of tigers had dropped to an estimated 3200. Thirteen countries in which tigers live signed an agreement to double their tiger populations by 2022. Explain why it is important to increase tiger populations and suggest ways of doing this.
5090_w23_qp_21
THEORY
2023
Paper 2, Variant 1
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Questions Discovered
23