Scientists talk about how much life there is on the planet but why do we care? What is so important about having different species? If there are so many species what difference does it make if we let a few disappear?
Biodiversity is critical for life as we know it. Plants produce the oxygen we breath. Bacteria decompose waste. Coral reefs protect islands from eroding into the sea. Many different creatures have roles in keeping the planet clean and giving us important resources. When biology helps people to survive, we call this ecosystem services. These services come in many forms but they rely on the interactions among many different species. Think of these interactions as a chain, each link represents a species. As you break these links the chain breaks. When enough species are gone ecosystems stop functioning, stopping the services they provided for us. Imagine a planet without oxygen…not the easiest place to survive!
Biodiversity is critical for life as we know it. Plants produce the oxygen we breath. Bacteria decompose waste. Coral reefs protect islands from eroding into the sea. Many different creatures have roles in keeping the planet clean and giving us important resources. When biology helps people to survive, we call this ecosystem services. These services come in many forms but they rely on the interactions among many different species. Think of these interactions as a chain, each link represents a species. As you break these links the chain breaks. When enough species are gone ecosystems stop functioning, stopping the services they provided for us. Imagine a planet without oxygen…not the easiest place to survive!
Clean water, air these types of services are critical for us but they are also critical for other organisms on the planet. We think of the inter relationships of different species as the threads of a spider web and each species are the connections. We often use this analogy to map out a food web. A food web shows which organisms each other organisms, typically with plants on the bottoms, herbivores above them and predators above the herbivores. As people we eat all of these levels of the food web, plants (like corn, broccoli, etc.), herbivores (cows, deer, etc.) and predators (tuna, etc.). As species go extinct connections on the web are broken and the organisms on higher levels no longer have as much to eat. If enough species from the bottom levels disappear then all of the upper levels collapse causing a cascade of species extinctions. Since we eat many of these organisms we should be actively working to preserve food webs to ensure we can feed people.
Our health and survival is important, and medicines are one of the ways that we stay healthy. Most medicines come from natural sources, this makes sense, for thousands of years native cultures found plants and animals that had medicinal uses. Even now this is still true, approximately 60% of our medicines come from natural sources. We are constantly finding new chemicals from plants that cure a range of problems from headaches (aspirin comes from the bark of a willow tree) to cancer (taxol is currently the most used anticancer medicine and is derived from an evergreen tree). A cone snail like the one in the photo to the right contains a potent pain killer compound. But there are a huge amount of species that we don’t even know about (see the last blog). Many of these land and marine species might contain chemicals that are useful medicines but we have never tested this. We don’t even know the names of these creatures let alone how they might help us survive. This is a real problem, imagine if we let a species go extinct that had the cure to breast cancer. Once the species goes extinct there is no way for us to know what chemicals they contained. This is especially true for marine creatures, we have only been looking for medicines in marine animals for the last 40 years. This corresponds to our ability to scuba dive, before that we were really limited in our ability to find marine creatures. But we have always been able to walk around a forest and eat a plant (there must have been a lot of trial and error in the beginning). Currently there are 3 medicines made from marine animals, but you can imagine this is just the tip of the iceberg.
As our population increases more and more human actions are affecting the ability of different organisms to survive. We don’t often interact with most of the biodiversity that lives on the planet, but there is a huge amount of different creatures on the planet that all have a role to play in their habitats. It is critical that we appreciate diversity not only for its beautiful variety but also for the services that these creatures provide to us. Extinction is the biggest threat to these services because the species that die are gone forever. There have been 5 previous mass extinctions when life on the planet changed dramatically, for instance when the dinosaurs died. Some scientists think that we are in the middle of the 6th mass extinction. We have seen many species go extinct in the last 10,000 years, a relatively rapid rate for species to disappear. We should be very worried, all of the life on the planet helps us to survive so if we are causing a mass extinction we are breaking more links in the chain and disrupting food webs. We need to do everything in our power to stop extinctions and preserve biodiversity. We only live on one planet, and we need to actively preserve the rich biodiversity we have.
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