19. Relationships of organisms with one another and with the environment
A section of Biology, 5090
Listing 10 of 282 questions
The pollution of air and water may result from human activity. This pollution can lead to many harmful effects on ecosystems. A knowledge of these harmful effects has led to a reduction in human activity that leads to this pollution. One human activity that may lead to pollution of air is the production of electricity. The graph shows changes in the release of gases into the air during the production of electricity over a period of 18 years by 32 countries. 1992 1994 1996 1998 2000 2002 2004 2006 2008 percentage concentration of gas compared with the concentration in 1990 year carbon dioxide key: sulfur dioxide oxides of nitrogen Describe, using data from the graph, the trends shown. During this period of 18 years, the total amount of electricity produced each year by the 32 countries increased. Suggest one change in the processes used by these countries to produce electricity that may account for the trends shown in the graph. Pollution of the air by each of the gases named in the graph leads to harmful effects on ecosystems. Suggest and explain the positive effects on ecosystems of the trends shown in the graph. A survey of the populations of several species of fish in part of a river was carried out in 2003 and again in 2007. The population of one species of fish decreased from 1385 to 28 over this period. Calculate the percentage decrease in the population of this species of fish. % The scientists who carried out the surveys suggested that the fish population might recover if conservation actions are taken. Suggest one possible conservation action that could be recommended by the scientists and describe how they could find out whether this action is successful.
5090_s20_qp_22
THEORY
2020
Paper 2, Variant 2
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Lake Washington in the United States of America is a large fresh water lake. Between 1941 and 1963 an increasing amount of untreated sewage polluted the lake. Suggest and explain the effect of this untreated sewage on the lake ecosystem. Between 1963 and 1968 new sewage treatment facilities were constructed. By 1968 the amount of untreated sewage entering Lake Washington was reduced to zero. shows how the transparency of water in the lake has changed over time. Water transparency is a measure of how far light travels through water. water transparency / m year Calculate the percentage increase in water transparency between 1957 and 1968. Space for working. % One species of fish that lives in Lake Washington is the Three Spined Stickleback. shows three different distribution patterns of armour plates on the skin of these fish. no armour plates armour plates low number of armour plates medium number of armour plates many armour plates Table 4.1 shows how the distribution patterns of armour plates on the skin of Three Spined Sticklebacks have changed over time. Table 4.1 year percentage of fish with each distribution low number of armour plates medium number of armour plates many armour plates Use data from Table 4.1 to describe how the distribution patterns of armour plates have changed over time. Armour plates on the skin of a Three Spined Stickleback protect it from predators. Describe how the process of natural selection may have caused these changes in the distribution of plates over time.
5090_s23_qp_22
THEORY
2023
Paper 2, Variant 2
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Lake Victoria, in Africa, is one of the largest fresh water lakes in the world. It is an important ecosystem for people living around the lake who catch fish as part of their diet. shows part of a food web for the lake. Nile perch Nile sardines young Nile perch great cormorants African fish eagles humans small photosynthesising organisms prawns Nile tilapia zooplankton (not to scale) State the name of an organism shown in that is: a primary consumer both a secondary consumer and a tertiary consumer. Humans eat Nile tilapia, prawns, Nile sardines and Nile perch. Use information from to state which of these is the least energy efficient for humans to eat and explain why. Suggest the effects on this ecosystem of increasing the mass of Nile tilapia taken from the lake by human fishing. Suggest and explain ways in which the fish populations of the Lake Victoria ecosystem can be managed so that they provide a sustainable resource. shows a diagram of the Nile perch gas exchange system and part of the circulatory system. heart key direction of blood flow gills Describe the similarities and differences between the human and Nile perch circulatory and respiratory systems. similarities differences
5090_w24_qp_21
THEORY
2024
Paper 2, Variant 1
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Questions Discovered
282