Final answer:
Introducing non-native, or invasive, species can lead to uncontrolled population growth and competition with native species due to a lack of predators and competition. They can also introduce new diseases, causing ecological imbalances and threatening biodiversity.
Step-by-step explanation:
Introducing non-native species into an ecosystem can result in several problematic outcomes. Often known as invasive species, these organisms can thrive to the detriment of native species by multiple means. Firstly, they may encounter a lack of natural predators or competitors, allowing their populations to grow unchecked. Secondly, invasive species might outcompete native species for vital resources or introduce diseases to which the locals have no immunity. Examples include certain plants like the Eurasian star thistle, which has invaded parts of the western United States, displacing native plant communities despite providing benefits for pollinators. The impact of these species is typically complex and multifaceted, leading to a significant rearrangement of the ecological balance.