Italian sparrows

• This species only exists because of humans! It evolved when house sparrows hybridised with Spanish sparrows.
• The ranges of the two species only overlapped because of the spread of agriculture. The house sparrow was native to central Asia, but as farming spread into Europe, perfect conditions were created for the house sparrow to spread too. Farms are good habitats for these generalist feeders, which eat spilt grain as well as weed seeds, insects and berries. This spread happened thousands of years ago, so house sparrows are classed as native to the UK even though they arrived here because of humans. 
• Eventually, the spread brought house sparrows into contact with Spanish sparrows in southern Europe. The two species bred with each other. Now, the Italian sparrow is a species in its own right – Italian sparrows do interbreed with Spanish sparrows still, but throughout most of their range Italian sparrows just breed among themselves.
• There are estimated to be between 4.3 million and 7.3 million Italian sparrows.
• The International Union for the Conservation of Nature (IUCN) lists the species as Vulnerable because it is declining. 
• We don’t know why the Italian sparrow is declining. House sparrows and Spanish sparrows are declining because of changing agricultural practices, such as increased use of pesticides, which reduce the amount of available food. This is likely to be the case for Italian sparrows too. However, urban populations may also be declining, so farming practices are unlikely to be the only cause of declines.
• The Italian sparrow is dependent on humans – living in and around towns, villages and farmland. This is a species entirely ‘in our hands’.
• There are lots of closely-related species: there are 28 species in the genus Passer.  The species in this genus are known as ‘true sparrows’ because American sparrows aren’t closely related, they were just given that name by European colonists because it was a word they were familiar with.  
• Professor Chris Thomas discusses the Italian sparrow in his book Inheritors of the Earth: how nature is thriving in the age of extinction, and points out that extinction is only one side of evolution in this video.
• Read about how the house sparrow has evolved to live alongside us. 

West Indian Ocean coelacanth

• Coelacanths were once thought to have gone extinct with the dinosaurs 65 million years ago, because they were only known from fossils. The first live one was discovered in South Africa in 1938. 
• The coelacanth is seen as a living fossil because it evolved so long ago and has changed very little since. The earliest fossils are from approximately 360 million years ago, and some scientists estimated they evolved around 400 mya – they evolved before the dinosaurs.
• There are two known surviving species of coelacanth: West Indian Ocean coelacanth and Indonesian coelacanth.
• The coelacanth’s most striking feature is paired lobe fins which look like legs, and move in an alternating pattern like a trotting horse. This makes them very agile. They are also unique among fish in having very thick scales; an oil-filled tube that acts as a backbone (a notochord); a unique rostral organ in their snout that is part of the electrosensory system; and a hinged joint in their skull which allows them to open their mouths wide enough to swallow large prey.
• The largest known population of the West Indian Ocean coelacanth lives along around the Comoro Islands in the Mozambique channel. Small numbers have also been found along the African coast from Kenya to South Africa.
• Coelacanths live in the ‘twilight zone’, generally between 100-500 m, off steep rocky slopes of volcanic islands. 
• They can grow up to 2 m. Adult females are an average of 82.1 kg and 170 cm; the smaller males are an average of 37.2 kg and 125 cm. Their bodies are covered in dark blue scales, with white speckling that is unique to each fish.
• Studies suggest they could live to over 100.
• The West Indian Ocean coelacanth is listed as Critically Endangered by the IUCN.  We know very little about how many there are or whether they are declining. There may only be a few hundred left. 
• It takes years for a female to reach maturity (perhaps over 50!) and they only have small numbers of offspring, so the population can only grow very slowly and is vulnerable to disturbances.
• The coelacanth isn’t fished for intentionally, but it is caught as bycatch.

Points to consider

There is no intrinsic reason why a species is less important if it evolved because of humans. Humans evolved as part of nature, so we shouldn’t be considered differently to other species. The impact of one species on another is a major driver of evolution, and our ancestors have always affected other species. It’s no wonder that the same is true of modern humans.

There are many examples of humans affecting evolution over different timescales. The barn swallow in Europe may have evolved over the last few thousand years to live in a human world, taking advantage of human structures for nesting. On a shorter timescale, we can see adaptations in other species. The peppered moth is the most well known, but other examples include cliff swallows in America. They evolved shorter wings so they are better able to avoid cars.  

Many people see the coelacanth’s long evolutionary history as a reason to preserve it. However, there’s no intrinsic reason why an organism is more important if it evolved a long time ago. You could even argue the opposite – that the coelacanth has had a very good innings, and it’s the turn of another evolutionary lineage to thrive. However, that argument is again simply a human judgement. 

There are, however, practical reasons that we may want to prioritise species that are more distinct. For a start, they capture people’s imaginations. It’s exciting to know that there are such fascinating species as the coelacanth, even if most of us will never see one. They are also scientifically important, and can help us understand evolution. Many scientists believe that coelacanths represent an early step in the evolution of fish into four-legged land animals like amphibians.

We can also think about future evolution. Perhaps genetically-distinct species will be better able to adapt to future conditions. The more evolutionary lineages that survive now, the more options there are for future evolution.  

However, sparrows are proving very adaptable to our new world, unlike coelacanths, so maybe they are a better evolutionary bet. They also have a greater impact on our lives, as they are much more common and live closer to people. Like coelacanths, Italian sparrows can help us understand evolution, given that they evolved rapidly and recently. 

The fact that there are so many more sparrows than coelacanths means that focussing on their conservation could also have much more of an impact on animal welfare. 

People spend a lot of time lamenting species extinctions caused by humans. Perhaps it’s time we celebrated the species we are creating!