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Artificial Selection: Choosing Traits on Purpose — Reading Comprehension

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MS-LS3-2

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This NGSS-aligned reading passage explains artificial selection, the process of humans choosing which traits to pass on in plants and animals. Students will learn how farmers and breeders select certain individuals with desirable traits, such as large fruit or gentle temperaments, to shape future generations. The passage contrasts artificial selection with natural selection, highlights benefits and risks—like reduced genetic diversity—and provides real-world examples like bananas and carrots. Supporting MS-LS3-2, this passage builds understanding of heredity, variation, and the role of humans in shaping genetic outcomes through sexual reproduction. Ideal for science reading comprehension and genetics instruction.

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"Illustration sinapis arvensis" by Carl Axel Magnus Lindman / Wikimedia Commons.

Artificial selection is the process by which humans choose which organisms will reproduce based on traits they find useful or desirable. Unlike natural selection, which happens in nature without human help, artificial selection is controlled by people. It has been used for thousands of years in farming, breeding, and gardening to produce better crops and animals.

Farmers and breeders use artificial selection to improve plants and animals. For example, farmers might choose the largest, juiciest tomatoes from a crop and only use the seeds from those plants for the next generation. Over time, this leads to tomato plants that consistently produce larger fruit. In animals, breeders may select dogs with gentle temperaments or horses with strong muscles, depending on what traits they want to keep passing on.

Artificial selection works by selecting which individuals are allowed to pass on their genes. This changes the gene pool over generations. Even though this is a type of sexual reproduction, the variation in offspring is influenced by human choices rather than natural environmental pressures.

There are some downsides to artificial selection. By focusing only on certain traits, humans may reduce genetic diversity, which can make a population more vulnerable to disease or changes in the environment. For example, most banana plants grown today are genetically identical, making them easier to farm—but also easier for pests and diseases to attack.

Still, artificial selection has played a huge role in shaping the foods we eat and the animals we live with today. From fluffy poodles to sweet seedless grapes, many of the traits we enjoy came from careful selection over generations.

Fun Fact: Wild carrots used to be small, bitter, and purple—today’s crunchy orange carrots are the result of hundreds of years of artificial selection!

What is artificial selection?

Nature choosing traitsRandom breedingHumans choosing traits to pass onTraits picked by chance

How is artificial selection different from natural selection?

It happens in oceansIt uses only insectsIt is controlled by humansIt stops traits from changing

What is one example of artificial selection in farming?

Letting plants grow wildPicking seeds from random plantsChoosing the largest tomatoes for seedsGrowing crops without water

What do breeders select in animals?

The tallest treesRandom fishTraits like strength or gentlenessCold weather animals

What risk comes with artificial selection?

Faster growthLoss of genetic diversityBetter healthStronger environments

Why are bananas at risk from pests?

They grow too slowlyThey all taste the sameThey are genetically identicalThey are only grown in winter