Even in nature, mixing is very important. Ecosystems are based on diversity: everyone has a role and the resulting balance benefits everyone. If the lion or the shark is missing, or if the bees or the microscopic algae are missing, a habitat collapses in a really short time. Biodiversity is a very young word – in fact it’s less than 100 years old – but it means the variety of living beings, all the differences between different species, such as between a whale and a hummingbird, between a daisy and a baobab. Not only that, this term also includes the differences between individuals of the same species that are often not seen at all: they’re details that seem irrelevant at first but actually have a specific reason for existing. A 3.8-billion-year-old experiment Biodiversity was born with the differentiation of the first cells that gave rise to life on our planet 3.8 billion years ago. Today, scientists have managed to catalogue nearly 2 million living species including animals and plants, fungi and algae, bacteria, archaea and protozoa. However, scientists estimate that there are at least 10 million living species on our planet. There are 8 million we don’t even know about yet, but they exist all around us: they’re tiny and are mainly found in pristine forests or on the still unexplored ocean floors. Mass extinctions are “normal” events on Earth. In the last 500 million years, it has already happened five times: life has been almost wiped out by climate change, intense glaciations, volcanic eruptions and even the impact of asteroids. But it has always recovered, giving rise to new species that have repopulated the planet. That’s why the birth and disappearance of living species are natural mechanisms that are part of evolution. But they’re very slow mechanisms: after each extinction it took millions of years for life to recover what it had lost. While in the past the causes have always been natural, today the behaviour of human beings has had a big impact... Biodiversity loss in 5 steps Three quarters of the terrestrial environment and about 66% of the marine environment have been modified by human actions. The five factors that are causing the loss of biodiversity due to anthropogenic (i.e. human) causes are: Over a third of the world's land surface and nearly 75% of freshwater resources are now devoted to crop or livestock production. According to the WWF, over a third of fish worldwide are subject to overfishing by illegal methods, the destruction of critical habitats or the capture of endangered species. In addition, 60% of fish stocks are exploited at full capacity, while only about 7% of fish are caught in a sustainable way. Greenhouse gas emissions have doubled since 1980, causing global average temperatures to rise: climate change is a serious threat to wildlife. Pollution has increased tenfold since 1980: 300-400 million tons of heavy metals, solvents, toxic sludge, plastics and other industrial waste are dumped each year into the world's waters. Invasive alien species – those transported by the direct or indirect action of man out of their natural areas – are the main cause of animal extinction and have caused a third of all known extinctions. Even if we don’t realize it, our daily actions risk increasing the loss of biodiversity; rethinking our consumption also means having greater respect for nature.
