Which of the following is an example of artificial selection: 5 real-world cases

Artificial selection is the process by which humans breed plants or animals to promote specific traits. One example is the development of modern corn from teosinte, a wild grass found in Mexico. This change took place over thousands of years through careful seed selection by early farmers.

Teosinte has small cobs with few kernels, each covered in a hard shell. The seeds are difficult to eat and do not disperse easily. Ancient farmers in Mesoamerica collected seeds from plants that had more and larger exposed kernels. By planting these seeds, they gradually altered the plant’s characteristics. Over many generations, this selection produced corn as we know it today.

A mutation in the teosinte glume architecture 1 (tga1) gene played a major role. This gene affects the hardness of the seed casing. The mutation resulted in softer, uncovered kernels that were easier to harvest and consume. Farmers did not understand genetics, but by consistently choosing the best plants for replanting, they favored this mutation. Over time, the plant became reliant on humans for reproduction because modern corn cannot disperse its seeds on its own.

Today’s corn has large ears with hundreds of soft kernels. This form did not arise from random mutation or environmental pressures. It resulted from continuous human decisions. The trait changes reflect human needs—such as higher yield and ease of harvest—rather than survival in the wild.

Natural selection depends on environmental adaptation, but artificial selection is shaped by human goals. In the case of corn, traits like edibility and productivity were prioritized. The plant lost some resilience and genetic variation in the process. Modern corn would not survive long without human care. Its success lies in its usefulness, not in independence.

Other examples of artificial selection include dog breeds, dairy cattle, and ornamental flowers. Dogs like Border Collies were bred for herding ability, while Bulldogs were selected for appearance, even though this has led to health problems. Dairy cows such as Holsteins produce much more milk than their ancestors due to selective breeding and artificial insemination. However, improvements in feed and farming practices also contribute, making it harder to separate genetic effects from external factors.

Cultivated roses differ from wild ones in petal number and blooming frequency. Wild roses have five petals and produce hips. Many ornamental varieties have multiple petals and bloom repeatedly. These changes often came later and involved hybridization. Corn’s evolution began earlier and relied only on seed selection, making it a clearer example.

Broiler chickens grow to market weight in five to six weeks, about half the time required in the mid-1900s. This rapid growth is due to selective breeding but causes health issues such as skeletal and heart problems. While this shows the strength of artificial selection, it raises animal welfare concerns. Corn does not carry these ethical complications, yet still demonstrates the mechanism effectively.

The shift from teosinte to maize is well documented. Genetic, archaeological, and agricultural data all confirm the transformation. The physical differences between the two plants are extreme. Without explanation, most people would not recognize them as related. This makes the example especially strong.

Some cases are less clear. Pesticide resistance in insects and antibiotic resistance in bacteria result from environmental pressures, not intentional breeding. These are examples of natural selection. True artificial selection requires deliberate mating choices over generations to increase desired traits.

The history of corn shows how small, repeated actions lead to major change. No single generation showed a dramatic shift. Over centuries, the cumulative effect was profound. Farmers only needed to save seeds from the best plants. This consistency created a crop that now feeds billions.

This process also shows how cultural values influence biology. Early Mesoamerican societies selected for traits they found useful. Human preferences became a force in evolution. The same principle applies in modern agriculture, pet breeding, and biotechnology.

Modern tools like genomic testing allow faster and more precise selection. But the core method remains unchanged. Whether selecting corn ears 9,000 years ago or using DNA markers today, humans control which genes are passed on. Artificial selection continues to shape living organisms.

The origin of corn remains one of the clearest examples of artificial selection. It links ancient farming with modern science. The visible differences, genetic evidence, and long history make it a direct and well-supported case. Among possible answers to “which of the following is an example of artificial selection,” the transformation from teosinte to maize stands out.

Key Takeaways

• Artificial selection is human-directed breeding to enhance specific traits in plants and animals.
• Modern corn evolved from teosinte through generations of selection for edible, accessible kernels Khan Academy.
• This transformation involved changes in key genes like tga1, leading to exposed, soft kernels and larger ears.
• Unlike natural selection, artificial selection reflects human preferences rather than environmental survival.
• While powerful, artificial selection can reduce genetic diversity and create dependence on human care.
• The corn example is especially strong due to clear morphological differences, genetic evidence, and historical continuity.