The Thin End

All life moves. Or, more precisely, all life moves purposefully.  This is true even for trees and plants.  Movement is essential for maintaining life.  Animals migrate; plants disperse.  Some form of migration is an ingredient of all life.  For many organisms, it is a key function of reproduction.  We don't reproduce merely to create a new organism, but also to disperse the population - finding new fertile ground, or resources. Reproduction is a form of migration. Reproduction isn't merely to replicate. Reproduction produces change and diversity.  While we may have strong resemblences in families, we also have differences.  Creating a difference is how evolution works.  In this sense, nature is a continuous exploratory process, finding what works best.  Nature senses change and responds.  Some of this is immediate and physiological or behavioural; some of it is over generations.  If we look at a forest over long periods of time...

Living in the grass is a tiny mouse: the tiny harvest mouse, with a wonderful scientific name that sounds like the title of a Charles Dickens Novel,  Micromys minutus.   It is the only British mammal with a prehensile tail. It uses its tail to hold on to the slender grass stems, at the tops of which it builds a nest. Photo: Nick Fewing These tiny mammals (just around 5 cm long) build a spherical nest of tightly woven grass at the top of tall grasses, in which the female will give birth to about six young.  In the fields, we see cows and horses brushing away flies with their tails; often they will stand side-by-side and end-to-end, and help each other.  Two tails are better than one!  In nature, tails are put to good use.  Just as a tight-rope walker uses his pole for balance, so for some species, a tail provides balance. When running, a squirrel uses its tail as a counterbalance to help the squirrel steer and turn quickly, and the tail is used aer...