“Sex pheromones are chemical compounds released by an animal that attract animals of the same species but opposite sex. They are often so specific that other species can’t smell them at all, which makes them useful as a secret communication line for just that species. But this specificity raises an intriguing question: When a new species evolves and uses a new pheromone signaling system, what comes first: the ability to make the pheromone or the ability to perceive it?
Here is the conundrum: Among species that use pheromonal signaling systems to attract mates, individuals that are detecting and responding to the scent (the receivers) are using the specificity of the signal as a measure of whether the individuals emitting the scent (the senders) are in fact the right species. Any individuals that make a new and different scent would then be perceived by the receivers as being the wrong species and they won’t attract any mates. If you don’t attract mates, you can’t pass on your new genes for your new scent. This produces a strong pressure to make a scent that is as similar as the scent produced by everyone else as possible (this is called stabilizing selection). With this intense pressure to be like everyone else, how did the incredible diversity of species-specific pheromones come to be?”
Scitable | Nature Education
“Humans are a plague on the Earth. It’s coming home to roost over the next 50 years or so. It’s not just climate change; it’s sheer space, places to grow food for this enormous horde.
Either we limit our population growth or the natural world will do it for us, and the natural world is doing it for us right now”
"Fifty years ago we didn’t have the technology to run these rivers. Fifty years from now many could be dammed. Now is the time to explore them and hope others follow.”
— Ben Stookberry