The table shows the mean mass of four types of rodent and the mean number of years they live.
Type of rodentMean mass (g)Mean number of years they liveDwarf hamster502.0Golden hamster1503.0Rat3505.0Guinea pig5507.0 \begin{array}{|l|c|c|} \hline \textbf{Type of rodent} & \textbf{Mean mass (g)} & \textbf{Mean number of years they live} \\\hline \text{Dwarf hamster} & 50 & 2.0 \\\hline \text{Golden hamster} & 150 & 3.0 \\\hline \text{Rat} & 350 & 5.0 \\\hline \text{Guinea pig} & 550 & 7.0 \\\hline \end{array} Type of rodentDwarf hamsterGolden hamsterRatGuinea pigMean mass (g)50150350550Mean number of years they live2.03.05.07.0Plot the data from the table on the graph. [2]
Draw a line of best fit through the points. [1]
House mice are rodents that have a mean mass of 20 g.
Use your graph to predict the mean number of years that house mice live.
Mean number = ............................................................ years [1]
Bats are small mammals that can live for over 30 years. This is much longer than predicted for mammals of their size. Scientists found that bat cells have highly efficient mechanisms to repair damaged DNA.
Explain how this would help bats to live much longer. [2]
Weddell seals spend a long time diving deep underwater to hunt for food.
During these dives, they cannot breathe air, so the oxygen levels in their blood drop very low.
Complete the sentences below to show how Weddell seals are adapted to survive deep dives.
Weddell seals can lower their heart rate during a dive. This means they consume less ............................................................ gas from their blood.
This gas is stored in large amounts in their red blood cells, bound to a protein called ............................................................ .
During a long dive, their muscle cells may respire anaerobically. This produces ............................................................ acid, which their tissues can tolerate in high concentrations.
Scientists think that seals have evolved these specialized diving adaptations by the process of ............................................................ . [4]