I was recently discussing science, evolution and conservation with a friend, who is not a trained scientist, and she asked me the following questions: (*Please note that she supports conservation and the work that people do in studying and conserving species.)
“Why is it important for sea turtles, or any animals for that matter, to be protected? Is it important that they be protected when they are living, or is it important to also protect their ability to produce and create offspring? If evolution is all life is really about, then doesn’t the fact that animals get extinct just go to show the natural order of things and that the strong devour the weak? Why is that a problem for us? Based on evolution and survival of the fittest, isn’t that the way things are supposed to work?”
These were good thought questions for me as I’m sure they will be asked often in my career. I know why I am dedicating my life to this cause, but hadn’t tried to explain it like this to someone before. Are you a conservationist, do get asked this often? How do you respond? I’ve shared my response to her below.
Why Should We Conserve?
There are so many reasons to conserve species/biodiversity that the details can be overwhelming. I’m going to keep it simple and focus on two of them. Yes, evolution by natural selection, simplified, is “survival of the fittest”. The fittest being those that can pass on the most genes to the next generation (not fit like going to the gym fit, although sometimes that allows individuals to pass on more genes). However, humans have altered natural selection pressures (mostly by resource limitations (food, habitat, etc.), but also competition). This creates artificial selection on wild organisms, and in many cases it is having negative effects. Thus the need for conservation (or the un-doing/fixing of our actions) is great and real.
One of the most recognizable examples of artificial selection is dog breeding.We have selected for particular traits in dogs to create breeds with combinations of traits that have never existed before human/dog interaction. Yes, evolutionary mechanisms dealing with gene frequencies did occur, but humans altered these over time.
In each generation there are variations in offspring. Breeders select the variation of the trait they are looking for (e.g. small body size in toy poodles, herding ability in sheep dogs or rodent hunting abilities in dachshunds) and mate those individuals with others that also exhibit the traits they want. Those that do not exhibit the desired traits are not bred. This process is repeated until they get the desired traits expressed. Take for example, the teacup poodle.
Put a domesticated, human altered toy poodle into the wild where wild dogs live (dogs that are evolutionarily related to the poodle) and who do you think would survive better? The wild dog, clearly. So due to human impact of altering selection pressures and creating artificial selection, we are altering organisms’ abilities to survive in natural habitats. Luckily for poodles, they generally don’t have to try to survive in natural habitats.
In the case of sea turtles, who have survived on earth for over 150 million years and live in nearly all parts of the world – they are impressive competitors. You don’t survive on earth for that long without being so. As adults, they have very few natural predators, forage efficiently and have amazing physiological adaptations to deal with things like fluctuating ocean temperatures, deep dive depths, and extended dive times. As hatchlings and juveniles they face an array of natural predators, and they get eaten – a natural part of the ecosystem in which they have lived for millions of years. In fact, this is a very important part of the ecosystem and another reason we should conserve them, but I will get to that later.
So, why are turtle populations endangered? If they’ve been able to survive for so long, why protect them? We have disrupted the natural ecosystem to which they are adapted, and in which they have thrived in for millions of years. With industrialized overfishing, unsustainable harvests and the amount of marine debris (especially plastics) entering their ecosystems- we have disrupted a natural habitat and have created one in which many animals have an increased struggle to survive. It is not that evolution is not occurring, but that we have created artificial pressures that are driving species, like sea turtles, towards extinction. It is hard (if not impossible) to outcompete something like plastic that will basically “live” forever (it will only break into smaller pieces, never actually going “away”). Over 267 marine species have been documented ingesting plastics (but that’s another post entirely). Basically, we are replacing a natural ecosystem, and natural selection pressures with artifacts that make it an “unfair” fight. This is why we need to conserve them, because we are causing the problems. As Dr. Archie Carr, the father of sea turtle biology and conservation, once said,
“There is no civilized way to escape the obligation to save them.”
In addition to protecting them from problems that we’ve caused, it is for our own benefit, as humans, to conserve them. Sea turtles, as with most organisms, provide important ecosystem functions that we need to survive and better our own fitness. The roles sea turtles play in the ecosystem include nutrient transport, prey, and predators. Many animals depend on sea turtles as prey and in some of the few natural ecosystems left, sea turtles transfer huge amounts of energy onto the beach when they nest. For example, at Escobilla beach in Mexico, arribadas (synchronous, mass nestings) of olive ridley sea turtles occur where tens of thousands of turtles nest, each laying a clutch of around 100 eggs. These eggs and the nesting mamas provide food for the animals on land, add nutrients to the sand and in some cases it has been found that plants near nesting beaches have increased marine-derived nitrogen.
Out in the water feeding green turtles keep the sea grasses trimmed (like natural lawnmowers) which helps prevent overgrowth. They displace small invertebrates in the process, which in turn feed nearby fish. Hawksbill turtles eat aggressive species of sponges, keeping them in check so they don’t overpower coral reefs. Leatherbacks, the largest living sea turtle species, feed exclusively on jellies, keeping jelly blooms from getting out of control.
Why does this all matter? We, inhabitants of Earth, are all connected. We depend on the health of the ecosystems. We count on them for resources (e.g. food), and species, like sea turtles, are key in keeping those ecosystems intact and functional. We need them as much as they now need us. We have created a problem and it’s up to us to be the solution. Luckily, there are many people working around the world, dedicating their lives to causes like this – for sea turtles and other aquatic and terrestrial species. However, despite their valiant efforts and the impressive progress that has been made, more still needs to be done.
So, why should we conserve? Whether the reason be anthropocentric, or sea turtle-centric – we should conserve because this is the one beautiful Earth and we need her.
(Thanks to my friends Sarah and Dan for feedback on this post.)