Artificial Selection

Artificial Selection

Middle School

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Learning Objectives

• Differentiate between artificial and natural selection and the role of humans.

• Describe how technologies influence the inheritance of desired traits in organisms.

• Explain how understanding genes and probability helps create technologies for desired outcomes.

• Analyze the societal impacts of technologies that influence inherited traits.

Key Vocabulary

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Artificial Selection

This is the process where humans intentionally breed plants or animals for very specific, desirable traits.

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Selective Breeding

This involves choosing parent organisms with the most desired traits to produce the next generation.

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Animal Husbandry

This is the specific branch of agriculture that is focused on the care and breeding of farm animals.

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Genetic Engineering

This is the scientific process of directly manipulating an organism's genes using biotechnology in a laboratory.

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Recombinant DNA

This is special DNA created in a lab by combining genetic material from multiple different sources.

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GMO

A Genetically Modified Organism (GMO) is any organism whose DNA has been altered using genetic engineering.

Key Vocabulary

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Gene Therapy

A medical technique used to replace or deactivate faulty genes to treat or cure a genetic disease.

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Inheritance

The biological process of passing genetic information and traits from parents to their children or offspring.

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Probability

The measure of the likelihood that a particular event or a specific genetic outcome will occur.

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Parental Traits

The specific characteristics or features of parent organisms that are selected for breeding future generations.

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What is Selective Breeding?

• Humans choose organisms with desired parental traits to reproduce, a form of artificial selection.

• Unlike in natural selection, human desires determine which genes get passed on.

• For example, breeding cows that produce the most milk influences inheritance.

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Multiple Choice

Which statement best defines selective breeding?

• A process where humans choose organisms with specific traits to reproduce.

• A process where organisms randomly develop new traits to survive.

• A process where nature selects the fittest organisms to survive.

• A process that only occurs in plants and not in animals.

Multiple Choice

What is the key difference between selective breeding and natural selection?

• Human choice determines which traits are passed on, rather than environmental pressures.

• It happens much faster than natural selection.

• It only works on animals, while natural selection only works on plants.

• It involves changing an organism's genes in a laboratory.

Multiple Choice

A dog breeder wants to produce a new generation of faster racing dogs. Which of the following strategies uses the principles of selective breeding to achieve this goal?

• Choosing to breed only the dogs that are the fastest runners.

• Training all dogs to run faster through daily exercise.

• Feeding the dogs a special diet to increase their energy.

• Allowing the dogs to mate randomly with each other.

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The Role of Genes and Probability

• Inheritance of traits depends on genes and follows the laws of probability.

• Each parent passes a specific combination of its genes to its offspring.

• Therefore, the inheritance of traits from parents to offspring is not always certain.

• Selective breeding increases the probability of desired traits appearing in the next generation.

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Multiple Choice

Which statement best describes the principle that governs how traits are passed from parents to offspring?

• It is determined by genes and follows the laws of probability.

• It is a completely certain and predictable process.

• It is influenced only by the traits of the stronger parent.

• It is determined by the offspring's environment after birth.

Multiple Choice

Why is the inheritance of traits from parents to offspring not always certain?

• Because each parent contributes a specific combination of genes, making the outcome a matter of chance.

• Because genes from one parent are always more dominant than the other.

• Because the number of offspring is too large to predict.

• Because environmental factors are more important than genes.

Multiple Choice

Based on the principles of inheritance, how does selective breeding work to promote specific traits?

• It guarantees that all offspring will have the desired trait.

• It increases the likelihood that genes for a desired trait will be passed to the next generation.

• It introduces new genes from the environment into the offspring.

• It ensures that offspring are completely different from their parents.

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Genetic Engineering and GMOs

• Genetic engineering directly changes an organism's DNA, unlike traditional selective breeding.

• Recombinant DNA combines genes from different species, like bacteria producing human insulin.

• Organisms with altered DNA are called Genetically Modified Organisms or GMOs.

• GMOs are used to create crops with traits like pest resistance.

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Multiple Choice

What is the key characteristic that defines genetic engineering?

• It is a method of traditional selective breeding.

• It only combines genes from the same species.

• It creates organisms that are identical to their parents.

• It directly changes an organism's DNA.

Multiple Choice

What is the relationship between recombinant DNA and a Genetically Modified Organism (GMO)?

• A GMO is a natural organism that produces recombinant DNA.

• Recombinant DNA is the technique used to create a GMO.

• Only bacteria can be GMOs, but all organisms have recombinant DNA.

• Recombinant DNA and GMOs are two terms for the same thing.

Multiple Choice

A scientist develops a new type of corn that is not eaten by insects. Based on the principles of genetic engineering, what is the most likely explanation for this new trait?

• The corn was created by selectively breeding the strongest plants.

• The corn's DNA was altered to include a gene for pest resistance.

• The pests' DNA was changed so they would not eat the corn.

• The corn was grown in a special soil that pests avoid.

Gene Therapy

• Gene therapy treats diseases by fixing faulty genes inside a patient's cells.

• A modified virus, or vector, delivers a correct copy of the gene.

• The new gene helps cells produce correct proteins to fix the genetic disorder.

Multiple Choice

What is the primary goal of gene therapy?

• To treat diseases by correcting faulty genes within cells.

• To create stronger, modified viruses for medical use.

• To remove and replace all of a patient's damaged cells.

• To study how different proteins affect the human body.

Multiple Choice

What is the specific function of a modified virus, or vector, in gene therapy?

• It acts as a delivery vehicle to carry the correct gene into cells.

• It destroys the faulty gene already present in the cells.

• It signals the cells to stop producing incorrect proteins.

• It combines with the faulty gene to make it work correctly.

Multiple Choice

If the new gene delivered during therapy fails to produce the correct proteins, what is the most likely outcome?

• The patient's genetic disorder would not be fixed.

• The cells would produce an excess of correct proteins.

• The vector would be ejected from the patient's cells.

• The faulty gene would be repaired instead of the new one working.

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Common Misconceptions

Misconception	Correction
Artificial selection is a modern invention.	Humans have practiced selective breeding for thousands of years.
Selective breeding guarantees perfect offspring.	It only increases the chance of passing on desired traits.
Science tells us how to use new technologies.	Science describes risks, but society makes the ethical decisions.
GMO foods are inherently dangerous.	Scientific consensus shows that GMOs are safe for consumption.

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Summary

• Humans influence trait inheritance through artificial selection and genetic engineering.

• Recombinant DNA technology creates GMOs, while gene therapy aims to correct genetic diseases.

• Knowledge of genes and probability helps improve the outcomes of these technologies.

• Scientific discovery and technological advances in genetics are interdependent.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

• 2

• 3

• 4