What are the most common causes of extinction?

Pasteurellosis may have killed more than 10,000 saiga antelope, but technically, people may still be to blame for the species' plight. Some scientists are dubbing the current era the planet's sixth mass extinction, and they're pointing their fingers back at us as the root cause since even small changes to the planet's delicate ecosystem can domino into catastrophe.

But as we try to take in the scope of how badly we've treated the planet, let's avoid the usual buzzwords like "unsustainable agriculture," "overharvesting" and "pollution," and really step into the shoes of the planet's plant and animal population. They're forced to maneuver a veritable minefield of threats in order to survive, dancing around (or more aptly, struggling to adapt to) deadly hazards every step of the way.

Vast landfills tainted by plastics and heavy metals, along with massive streams of contaminated wastewater, pollute both soil and waterways. Huge oil spills cloud ocean waters and mammoth stretches of pavement coat once viable land. Airplanes and high-rise buildings present aerial obstacles, and farms and family homes suck up habitat. Speaking of commercial farming operations, they waste water and leach dangerous pesticides into the environment. Houses are hotbeds of chemicals as well, containing everything from cleaning products to beauty supplies. Global warming cooks oceans and lands alike, and dams and reservoirs block migration routes in lakes and streams. Ocean traffic and road traffic both contribute to dangerous levels of light pollution, noise pollution and death through collisions. Slash-and-burn practices destroy forest ecosystems faster than we can discover and study the untold numbers of species they contain, and strip mining wipes out entire mountain ranges. Invasive species threaten native populations, and the spread of hyperviral pathogens grows easier by the decade.

The basic point is this: It took an enormous asteroid slamming into the planet at fantastic speeds to alter the Earth enough to accelerate the last major extinction event. This time around, we might be that asteroid.