B1-B3 June 2016 Higher

Explain who conclusions best matches the results in the diagram (2)
Charlotte’s is best match because:
She has correctly identified that the roots (are negatively phototropic) grow away from light  (1) 
She is correct with (positively geotropic) roots grow down due to gravity / Alan’s incorrect with negatively geotropic (1)
Suggest why the trail was designed in this way, and explain what the results show (6)
Design · to test the effects of a placebo on reaction time  · placebo effect when given/not given any nicotine · need to use a method to make sure that human mind / psychological effects / bias has not influenced results · placebo used to compare effectiveness of nicotine / show the effect of nicotine
 
Results · faster reaction times with nicotine / ORA · faster reaction time if they think they have nicotine  · placebo has an effect on results · placebo has less of an effect than nicotine            · results show that nicotine has a bigger effect than placebo even when people are told they’ve been given a placebo

The chanbges in tiger habitats have increased the risk of the extinction of tigers. Edxplain why (3)
tiger habitat smaller area / fragmented area / has reduced to critical level / drastically fallen between 1900 and 1990 (1)
max two for explanation: increased competition (1)  
reduced variation (1) 
too few survive to maintain a population /  reduced breeding success (1)
 If populations of organisms become isolated, new species are more likely to develop. Explain why (2)
organisms cannot exchange genes with wider population AW (1)
mutations / organisms adapt to change / different selective pressures (1)
features have changed so much can’t successfully interbreed AW (1)
Which time period shows the human population increasing exponentially? (1)
1940 to 1980
What are the possible consequences of exponential growth for the human population? (2)
food shortage / famine (1) water shortage (1) more disease (1)  lack of space / overcrowding (1) lack of resources / poor sanitation / lack of health care (1) increased pollution (1

Calculate the rate of population growth fro 1800 to 1880 by finding the gradient of the graph (2)
0.6/80
Explain how exponential growth may make sustainable develpment very difficult (2)
if the population is too large resources would not meet demand (1) 
because the time to replenish resources would be too long (1)
Calculate the efficiency of energy transfer from the plants to the sheep. Exp,ain how energy is lost from this food chain, and why this limits the length of the food chain (6)
energy loss · lost as heat / from respiration  · lost in excretion · lost in egestion · not all parts of plant / sheep are eaten / digested
calculation
· 4000 x 100   = 2% efficiency from plants to sheep    200000                      
length of chain
· very little energy gets passed from one level to the next  · not enough energy left to support another trophic level

Look at the diagram of the heart. Which part pumps blood around the body? (2)
D as it has a thicker wall (2)
Suggest how the procedure will be different. Explain your answr (Situs inversus) (2)
idea that heart would need to be turned round / placed back to front (1)
to allow connection to the correct blood vessels (1)
Discuss the advan and disadvan to this aspen forest of repooducing by cloning. Use info fro the newspaper article, as well as your own knowledge (6)
Advantages · can reproduce even though all plants are male / sexual reproduction is unlikely · more reliable than seeds · less energy wasted than reproducing sexually / producing seeds  · reproduction is quicker · if these trees are adapted to this environment then any new ones will also be adapted 
Disadvantages · lack of genetic variation · if one tree gets a disease then all may get it · if one is affected by any environmental change then they will all be susceptible · dispersal limited
Why is cloning more common in palnts than animals? (1)
idea that (many) plants/plant cells retain ability to differentiate but animals/animal cells do not (1)
Write down one advan of measuring dry mass compared with measuruing wet mass (1)
measures biomass / wet mass is too variable (1)

What is oxygen debt? (1)
idea it’s the amount of oxygen needed if all the energy released was from aerobic respiration (1) 
Area b is equal in size to area a (1)
the oxygen needed to repay the oxygen debt (1)
Explain the shape of the grapj for substance x. In your answr include what substance x is (2)
lactic acid (1)
produced during exercise (because of anaerobic respiration) and removed after exercise / when resting (1)