Evolution Under Pressure: How We Change Nature and How Nature Changes Us
Understanding what evolution is and isn’t is helpful in trying to answer these questions The theory of evolution based on natural selection is a good place to start But to really understand our role on Earth and the effect humans have had on the evolution of all other species including ourselves we can also look at the idea of not-so-natural selection What do animals like hornless rhinos porky pigs peppered moths and anole lizards have in common They’re all good examples of not-so-natural selection showing us how hunting farming inventing and even moving to the city can have a huge impact on other animals None of these human activities are bad We’ve always had an impact on other creatures just like other creatures have an impact on us The problem is through not-so-natural selection human activity has had a bigger impact on the environment and the creatures within it We’ve changed the way the world works interrupting the natural evolution of almost everything and pretty quickly So what now It’s not like we can go back in time and un-invent things And no one wants to go back to a time when we didn’t live such a comfortable life How do we decrease the impact of human activity in a way that works for all creatures How do we exist as part of the large tree of life without breaking too many branches 2 EVOLUTION UNDER PRESSURE
To start we’ll take a quick trip back to the beginning and look at our own evolution How did we start hunting farming and building factories and cities How have these activities changed as humans have evolved Then we’ll look at some specific characteristics from horns and feet to appearance and attitude to understand how not-so-natural selection has interrupted the evolution of certain animals Looking forward we need to be more aware of where we’ve been and where we’re going It’s not too late for humans to make choices that go beyond what’s best for us and consider what’s best for all of us from amoebas spiders and moths to rhinos lizards pigs and humans Humans might be significantly different than every other crea ture on the planet But that doesn’t mean we aren’t dependent on our fellow creatures for survival Every living creature needs a healthy ecosystem to thrive And as the animal with the largest impact it’s time for humans to ensure there’s enough room and trees for everyone Because it’s about all of us we’re all interconnected INTRODUCTION 3
How Selection Drives Evolution Natural and Not-So-Natural Chapter one 4
Evolution is the gradual development of something simple into something more complex like your science project chang ing from a page of notes into a multimedia presentation with slides a light show and an exploding volcano Depending on who you ask you your teacher or the classmate who got covered in a slimy mix of vinegar and baking soda one is not necessarily better than the other but one is definitely more complex You could say the presentation evolved from the notes just like the notes evolved from a blank piece of paper It’s important to remember that the page of notes you worked so hard to create still exists It could survive for a long time as is in a box of school treasures or it could evolve into something else an essay an exam study sheet or the lining of your hamster’s cage When we apply this idea of evolution to the development of life on Earth it’s often seen as a line with a beginning and an end we started as apes monkeys fish choose your ancestor and ended up as perfectly evolved humans The problem It’s not that simple Things actually started way before apes monkeys and fish with a stew of chemicals and molecules most of us would not consider life From there single-celled organisms with the ability to reproduce emerged As these single-celled organisms multiplied changes occurred by random chance This led to variation eventually resulting in every organism we share the planet with today 5
