Faithful readers will have noticed a lot of wildlife photos on this blog. My father had a great love of animals — we were regularly rescuing injured birds and feeding area squirrels — and instilled it in me. In high school I loved my first biology class, and decided that would be my career path. I entered university with the idea of eventually doing cancer research, but I landed my first summer job with the Ministry of the Environment, and that changed my focus. I majored in Ecology: the study of how the entire world, from the creatures that hang around a pond in a forest to everything on this planet, is interconnected. Every segment is critical, and we humans have arrogantly ignored that for the most part.

People often speak of the ‘circle of life’ in Africa, where it’s obvious and transparent. In the photo above, taken in the Masai Mara National Reserve in Kenya, a large pride of lions had killed a zebra and were enjoying dinner late in the afternoon. Scenes like that epitomize life in Africa: the loss of a zebra feeds an entire family of lions. This was an important meal for the lions, as their species is listed as ‘vulnerable’, only one step away from ‘endangered’. Yes, the top predator in Africa isn’t doing well at surviving.

As we watched the lions eat, other species gathered around. First the jackals showed up. They’re called “opportunistic” predators — they’ll hunt small animals and birds, and will scavenge from larger kills.

It didn’t take much longer for the vultures to arrive.

Both of these serve as cleaners in the ecosystem. By the time they’ve finished off what the lions haven’t eaten, there’s no longer any meat to decay and attract pests. They’re an essential segment of the circle of life.

And while we feel awful for the animal that was killed, we understand that if the lionesses don’t make the kill, their little cubs won’t eat either.

We permit species to die off at our own peril, not to mention losing the beauty and gift of their existence.

It’s hard to convey how beautiful lions are when you see them in the wild. Their rippling golden fur and mesmerizing golden eyes just can’t be adequately captured by a camera. I took a lot of photos trying.

Can you imagine a world without lions? Within our lifetime that’s a real possibility. Future generations may never be able to go and see a lion walking the plains of Kenya, or Botswana, or South Africa. And every species that we lose is one more piece out of the global ecosystem that supports all of us. If we lose enough pieces, that ecosystem will no longer work.

On World Wildlife Day, you can help by adding your voice to the groups doing their best to prevent further species erosion. You can find out more on the Global Citizen website.