2.1 Spend two minutes skim reading the passage below, so that you are familiar with the type of information it contains.
What is the main purpose of the passage?
to describe the habitat and eating habits of one specific animal
to explain the background to a proposed study into tropical animals
to argue that scientists can learn a great deal from studying nature
to give the findings of new research into an animals’s behaviour
How geckos cope with wet feet
Geckos are remarkable little lizards, clinging to almost any dry surface, and Alyssa Stark, from the University of Akron, US, explains that they appear to be equally happy scampering through tropical rainforest canopies as they are in urban settings. A lot of gecko studies look at the very small adhesive structures on their toes to understand how the system works at the animals grip surfaces with microscopic hairs on the soles of their feet, which make close enough contact to be attracted to the surface by the minute forces between atoms.
However, she and her colleagues Timothy Sullivan and Peter Niewiarowski were curious about how the lizards cope on surfaces in their natural habitat. Explaining that previous studies had focused on the reptiles clinging to artificial dry surfaces, Stark says ‘We know they are in tropical environments that probably have a lot of rain and geckos don’t suddenly fall out of the trees when it’s wet.’Yet, the animals do seem to have trouble getting a grip on smooth, wet, artificial surfaces, sliding down wet vertical glass after several steps. The team decided to find out how geckos with wet feet cope on both wet and dry surfaces.
First, they had to find out how well their geckos clung onto glass with dry feet. Fitting a tiny harness around the lizard’s pelvis and gently lowering the animal onto a plate of smooth glass, Stark and Sullivan allowed the animal to become well attached before connecting the harness to a tiny motor and gently pulling the lizard until it came unstuck. The geckos hung on tenaciously, and only came unstuck at forces of around 20N – about 20 times their own body weight. “In my view, the gecko attachment system is over – designed’, says Stark.
Next, the trio sprayed the glass plate with a midst of water and re-tested the lizards, but this time the animals had problems holding tight. The droplets were interfering with the lizards’ attachment mechanism, but it wasn’t clear how. And when the team immersed the geckos in a bath of room – temperature water with a smooth glass bottom, the animals were completely unable to anchor themselves to the smooth surface. ‘The toes are super – hydrophobic’, (i.e. water repellant) explains Stark, who could see a silvery bubble of air around their toes. But, they were unable to displace the water around their feet to make the tight contact that usually keeps geckos in place.
Then the team tested the lizard’s adhesive forces on the dry surface when their feet had been soaking for 90 minutes, and found that the lizards could barley hold on, detaching when they were pulled with a force roughly equalling their own weight. ‘That might be the sliding behaviour that we see when the geckos climb vertically up misted glass’, says Stark. So, geckos climbing on wet surfaces with damp feet are constantly on the verge of slipping and Stark adds that when the soggy lizards were faced with the misted and immersed horizontal surfaces, they slipped as soon as the rig started pulling. Therefore geckos can walk on wet surfaces, as long as their feet are reasonably dry. However, as soon as their feet get wet, they are barely able to hang on it takes geckos to recover from a drenching.
2.2 Look at this task based on the Reading passage. For each question, underline the type of information you need to scan for. The first two have been done for you.
Which paragraph contains the following information?
N.B You may use any letter more than once
Write the correct letter, A-E next to questions 1-7 below.
visual evidence of the gecko’s ability to resist water
a question that is yet to be answered by the researchers
the method used to calculate the gripping power of geckos
the researcher’s opinion of the gecko’s gripping ability
a mention pf the different environments where geckos can be found
the contrast between Stark’s research and the work of other researchers
the definition of a scientific term
2.3 It is important to fully understand what you are looking for in the passage. Answer these questions, based on Question1 in the task above.
1) Which of the following do you think is ‘visual evidence?’
A) something the researchers believe
B) something the researchers have seen
C) something the researchers have read about
2) Which of the following means the same as ‘ability to resist water?’
A) soaks up water
B) sinks in water
C) stops water getting in
3) Scan the passage to find ‘visual evidence’ of an ability to resist water. Which paragraph contains information?
2.4 Study Questions 2-7 in 2.2 carefully and match them to paragraphs A-E. Remember, the questions are not in the same order as the passage. This is because your task is to find out where the information is.