We will start by investigating what biodiversity actually is and where it can be found. This will include a look at the processes that drive the evolution of a new species and what we mean by the term ‘species’. We will learn why islands are special and often contain large numbers of species that are not found anywhere else. We will also investigate why there are generally more species per area nearer the equator and progressively fewer the further you travel to the north and south.
The later parts of the course will get slightly more depressing. We will start by tracking some of the extinction events that have occurred in recent millennia and why most of the really large mammals and birds have disappeared from the world over the last 40,000 years. As Alfred Russell Wallace, the co-discoverer of Natural Selection put it “we live in a zoologically impoverished world, from which all the hugest, and fiercest, and strangest forms have recently disappeared” (Alfred Russell Wallace, 1876). We will learn about more recent extinction events and reductions in the ranges and abundances that have and are occurring in even common species. To document this we will rely on data from museum specimens that provide an invaluable record of the distribution of species collected in decades past. We will also investigate more recent attempts to catalogue changes in the distribution of groups of species over large areas, relying on the work of dedicated volunteers.
Having examined the evidence for extinctions and declines in species’ ranges and abundances, we will then investigate the causes of these declines. In recent times this has largely been due to human impacts. We will focus on some key drivers and their interactions that can lead to extinctions. In particular, drawing on examples from around the world, we will investigate the impact of habitat change, the effect of introduced species, the results of pesticide use, and the current and projected future impacts of global warming. We will also consider the underlying cause of many of these stresses – increasing demands for food and resources by a growing and increasingly-demanding global population.
In the last part of the course we take a more positive spin on the situation to learn about what can and is being done to reduce and reverse species’ declines. We will also investigate why biodiversity loss matters and why the natural world should be conserved. We will finish by identifying different management and conservation techniques that can help conservationists, agronomists and governments to reduce the negative impacts of development on the environment.