Question

Inheritance of Traits



Humans have been shaping the traits of organisms for thousands of years. The methods for changing desirable traits have evolved as new technologies have become available.

In the aquaculture industry (fish farming), fish are selectively bred to have desirable traits in order to be more profitable. Desirable traits such as quick growth, resistance to disease, efficient feed-to-growth ratio, ability to tolerate a range of environmental conditions, and high meat yield are all characteristics that are selected and bred for. Sometimes, fish are genetically modified through gene editing to have specific traits. Selective breeding and genetic modification have evolved the genes of many fish species over time and caused a decrease in the genetic diversity of many fish species.



One of the ways fish are farmed is by creating enclosures in the open ocean where fish are grown and collected. These fish are often non-native to the areas in which they are farmed. Various drugs, herbicides, and foods containing non-native fish meal, fish oil, and fish eggs, are often added to the water in the fish enclosures. The diagram shows many of the environmental risks associated with this type of aquaculture.







When farmed fish escape from aquaculture settings, they can impact the surrounding native species and ecosystems. This can cause increased competition of resources for the native species, causing organisms with the most beneficial traits to survive and reproduce. This process is known as natural selection.



Fish are specially adapted to live in a specific range of environmental conditions. When the temperature or salinity of water varies outside these ranges, fish are more susceptible to diseases and death. Fish that are more tolerant to environmental changes are selected for in aquaculture. Which statement BEST describes how selecting for fish tolerant to environmental changes affects their probability of survival?


It increases the fish's probability of survival by decreasing their chances of disease.


It increases the fish's probability of survival by increasing their chances of disease.


It decreased the fish's probability of survival by decreasing their chances of disease.


It decreased the fish's probability of survival by increasing their chances of disease.

Answer 1

It increases the fish's probability of survival by decreasing their chances of disease.

Explanation: Fish tolerant of environmental changes experience less physiological stress and are less likely to become sick under variable conditions, so they survive and reproduce at higher rates.