PHOTOS: GETTY X2, SCIENCE PHOTO LIBRARY
Most fish have an immune system similar to other animals with
backbones. They produce antibodies that detect and bind to
substances invading the body, like viruses and bacteria, and instruct
white blood cells to destroy them. Just like in humans, it’s possible
to vaccinate a fish against future infections by exposing them to
a less virulent strain of a disease-causing microbe. Fish also cover
themselves in a layer of sticky mucus that traps microbes and contains
antimicrobial chemicals. The more stressed a fish gets, the more
infection-fighting goo it makes. HSDo fish have
an immune
system?Why didn’t
dinosaurs evolve to
be more intelligent?
They did! Dinosaurs evolved into modern birds
and some of them are extremely intelligent.
In Japan, there are crows that have learnt to use
the traffic to crack the shells of nuts that they drop- and they will wait for the lights to turn red,
so they can safely retrieve them.
One reason that birds still aren’t as intelligent as
humans is that a heavy, energy-hungry brain
doesn’t mix well with birds’ main adaptive
advantage – flying. It’s important to realise that
intelligence isn’t the goal of evolution,
nor is it always the best adaptation to
the environment. The enormous sauropod
dinosaurs lasted on the planet for 100 million
years, despite their tiny brains. We’ve had
‘intelligence’ for just a few million years, so it’s too
early to say whether it is a better strategy. LV
Why do wagon wheels sometimes
seem to move slowly in old films?Films are shot as a series of individual frames taken at around
24 per second. If the wagon wheel is rotating at precisely the right
rate, then a spoke in one frame will have been taken up by another
spoke in the next frame, creating the impression the wheel is
stationary. If they’re slightly out of sync, however, the wheels
will appear to move in slow motion. RM| & ANSWERSQUESTIONS14 June 2017Archaeopteryx was
an animal that shared
features of both
dinosaurs and
modern birds