Final answer:
Selective harvesting and environmental conditions within an aquarium can significantly impact organism abundance and diversity. For example, harvesting colorful fish over dull-colored individuals creates a selective pressure that can change the population's genetic make-up. Proper management and sustainable sourcing are vital to maintain or enhance biodiversity in aquaria.
Step-by-step explanation:
The abundance and diversity of organisms in an aquarium are influenced by various factors, including harvest for the pet trade and environmental conditions within the tank. Coral reefs, which host about 1/3 of the world's marine fish species, provide a glimpse into the delicate balance of marine ecosystems that can be replicated in an aquarium. When species are harvested unsustainably for home aquaria, it can lead to declines in their populations. Additionally, when an aquarium is released into the wild, it can introduce non-native species, disrupting local ecosystems and potentially leading to invasive species problems. In the case described with the colorful fish being selected for an aquarium, a selective pressure is created in favor of the muted-colored fish, likely altering the genetic diversity and the makeup of the population over time.
Changes within an aquarium ecosystem can also be observed in experiments that monitor water quality and its effects on life forms, such as algae bloom inhibited by larger dissolved organic carbon (DOC) particles, which block sunlight due to fish diversity in the tank. Whether an aquarium nurtures or harms biodiversity depends largely on the source of its inhabitants and the care it receives. Responsible aquaria management and sustainable practices are necessary for maintaining or enhancing biodiversity even on a small scale like a home aquarium.