Final answer:
Habitat loss, overharvesting, introduction of exotic species, and anthropogenic climate change are major environmental changes caused by humans, posing threats to biodiversity.
Step-by-step explanation:
Major Environmental Changes Caused by Humans:
- Habitat Loss: This occurs through activities such as deforestation and damming of rivers, leading to the destruction of natural habitats.
- Overharvesting: The excessive harvesting of resources, particularly aquatic species and bush meat in the humid tropics, threatens many species.
- Introduction of Exotic Species: Exotic species, introduced through human activities like trade and transportation, can cause extinctions and disrupt native ecosystems.
- Anthropogenic Climate Change: Although not yet a major impact, it is predicted to become significant in the future and is a consequence of human population's need for energy and fossil fuel use.
The consequences and threats of these changes to biodiversity include the loss of species, disruption of ecosystems, and potential extinction of vulnerable organisms.