It's impossible to definitively say which species has the *greatest* impact on the biosphere, as "impact" can be measured in many ways. However, it's clear that humans (Homo sapiens) have an undeniably significant impact on the planet, perhaps surpassing any other species in history. Here's why:

* Global Distribution: Humans inhabit nearly every corner of the globe, influencing ecosystems across the board.

* Resource Consumption: Our species consumes resources at an unprecedented rate, impacting food webs, water availability, and land use.

* Climate Change: Human activities are the primary driver of climate change, with consequences for biodiversity, weather patterns, and ocean health.

* Habitat Modification: We transform landscapes through agriculture, urbanization, and deforestation, disrupting natural ecosystems and threatening countless species.

* Biodiversity Loss: Our actions are a leading cause of biodiversity loss, with extinction rates accelerating.

* Pollution: We contaminate air, water, and soil with pollutants, harming wildlife and ecosystems.

While other species have significant impacts, humans are unique in their ability to alter the biosphere on a global scale, with far-reaching consequences. This makes us the single species with the most profound and widespread impact on the planet.