Final answer:
The primary cause of species extinction is habitat destruction due to human activities like agricultural expansion, urban development, and logging. Additionally, the introduction of exotic species and over-harvesting significantly contribute to the loss of biodiversity, with serious implications for global ecosystems and human welfare.
Step-by-step explanation:
The main reason that species are being lost to extinction is habitat destruction. This is largely due to various human activities, including farming, logging, urban development, and building infrastructure such as roads. Such activities alter natural habitats so significantly that they no longer support the species that once lived there. Additional significant causes include the introduction of exotic species, which can out-compete native species for resources, and over-harvesting, which depletes species populations faster than they can recover. Human-caused extinctions are happening at a rate comparable to the five previous mass extinctions in Earth's history, which were due to natural cataclysmic events. However, the current extinction crisis differs as it is driven by human activities.
The loss of biodiversity has serious implications, including the collapse of ecosystems and increased costs for maintaining food production, clean air and water, and human health. It's important to address the drivers of habitat loss and fragmentation, the spread of non-native species, and unsustainable harvesting to mitigate the ongoing loss of biodiversity.