Fig. 1 shows a fish ladder beside a dam. Adult salmon swim upstream through a series of pools to reach the river where they hatched. Some salmon are fitted ...
Question 1 Report
Fig. 1 shows a fish ladder beside a dam. Adult salmon swim upstream through a series of pools to reach the river where they hatched. Some salmon are fitted with harmless tracking tags.
(a) Name the long-distance movement of salmon to a breeding site. [1]
(b) Suggest how a tracking tag could help scientists identify which route a salmon uses. [2]
(c) Describe one reason why salmon returning to their natal river is useful for reproduction. [2]
Fig. 1 shows an automatic feeder used at a garden bird survey. The feeder opens at 06:00 and a camera records visits by blue tits during the day. The same amount of seed is placed in the feeder every day.
(a) Suggest why the researcher uses a camera instead of standing beside the feeder. [2]
(b) Name one environmental factor that could affect the number of visits. [1]
(c) Describe how the researcher could compare bird activity in summer and winter fairly. [2]
Answer Details
Salmon: (a) Long-distance movement to a breeding site is migration [1].
(b) The tag’s position can be detected and recorded at points along the river [1]. These recorded locations show the route travelled [1].
(c) Returning to the natal river brings adults to suitable spawning habitat [1], where males and females from the same population are likely to meet and release eggs and sperm [1].
Blue tits: (a) A camera avoids disturbing or frightening birds [1] and provides a continuous or permanent record of visits [1].
(b) Temperature is one environmental factor that could affect visit number [1]. Rainfall, wind, daylight and predators are also acceptable.
(c) Record for equal time periods in both seasons [1], using the same feeder, seed amount and location, and repeat over several days [1]. This makes season the main changing variable.
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