BBC_Science_Focus_-_08.2019

Q&A

GETTY IMAGES X2, SCIENCE PHOTO LIBRARY ILLUSTRATIONS: DAN BRIGHT

NATRE’S WEIRDEST CREATRES...

ANDREW CIREL, VIA EMAIL

WHY DON’T VIRUSES LIKE THE FLU DIE OFF WHEN

NO ONE IS ILL?

Strictly speaking, viruses can’t ‘die o’ as they’re just

inanimate strips of genetic material plus other

molecules. But the reason that they keep coming back

is because they’re always infecting someone

somewhere; it’s just that at certain times of the year,

they’re less able to infect enough people to trigger a

full-blown epidemic.

Many viruses are up during the winter because

people spend more time indoors in poorly-ventilated

spaces, breathing in virus-laden air and touching

contaminated surfaces. The shorter days also lead to

lower levels of vitamin D, and this weakens our

disease-fighting immune system. Experiments also

suggest that the u virus in particular remains

infectious for longer in low temperatures.

But even when conditions aren’t ideal, viruses will

find enough people to infect to ensure their survival,

until they can come roaring back in an epidemic. RM

It’s an association that starts

early: when primary school

children are asked to draw a

scientist or ‘smar t person’, they

tend to depict them with

glasses (perhaps influenced by

spectacle-wearing characters

like Harry Potter). This

association may be because we

tend to assume that short-

sighted people are more

‘bookish’ – a stereotype with

more than a grain of truth. Lack

of time spent outside has been

shown to contribute to

short-sightedness, as has time

spent engaging in close-up

work such as reading. CJ

ROSIE STEVENSON, DERBY

WHY DO GLASSES

MAKE PEOPLE

LO RE

INTELLI

WEEK NUMBER

% NHS 111 CALLS RELATING TO COLD/FLU

40

3.0

2.5

2.0

1.5

1.0

0.5

0.0

42 44 46 48 50 52 2 4 6 8 10 12 14

2016/17

2017/18

2018/19

Deep in the woods lurks a

creature with no mouth, eyes, or

brain. An oozing, yellow mass

that thrives in decaying leaves

and logs. Let’s celebrate

Physarum polycephalum – a

species of slime mould that

thinks without a mind.

In its early life, this creature

exists as a single-celled

organism. But when times get

tough, it has a trick up its sleeve.

Each P. polycephalum can

merge with the individuals

surrounding it, forming a

super-sized cell that’s capable of

reaching a metre in length that

can slowly creep towards nearby

food (usually fungal spores

and bacteria).

Recently, P. polycephalum has

become the lab rat of slime

mould research. It’s able to

escape from traps and find its

way around mazes, and it’s been

shown, when given a choice, to

seek out the most nutritious

food – porridge oats, apparently.

A particularly memorable

experiment involved

P. polycephalum gradually

learning to ‘ignore’ chemicals

that had been placed to block its

path to food. This behaviour

suggests a primitive form of

memory, and no one knows

quite how it manages this feat.

Worldwide, there are thought

to be around 900 slime mould

species, yet many more are

likely awaiting discovery. You

may think them primitive,

certainly, but you’d be wrong.

What we achieve in a trillion

cells, they manage with

just one. JH

SLIME MOULD (PHYSARUM POLYCEPHALUM)