Question

Jenny has brown hair and blue eyes and is \(5^{\prime} 8^{\prime \prime \prime}\) tall. What is being described is Jenny's: A. genotype. B. phenotype. C. somatotype. D. physique.

Short answer

Answer: B. phenotype.

Step-by-step solution

Define the terms

To understand which term is being described, let's first define each term: - Genotype: A genotype is a set of genes responsible for specific traits or characteristics. It is the genetic makeup of an individual. - Phenotype: The phenotype is the physical expression of an individual's genotype. It is the observable characteristics or traits, such as hair color, eye color, height, and skin color. - Somatotype: Somatotype refers to an individual's body type, which is determined by the level of development and proportion of three main components: ectomorph (thin and linear), mesomorph (muscular and athletic), and endomorph (rounded and soft). - Physique: Physique is the structure, proportions, and makeup of an individual's body; it is generally used to describe the observable physical appearance.

Analyze the given information

The given description is about Jenny's physical appearance - her brown hair, blue eyes, and her height ($5^{\prime} 8^{\prime \prime \prime}$ tall).

Identify the correct term

Based on the definitions provided in Step 1, Jenny's brown hair, blue eyes, and height are her observable characteristics or traits, which makes the description related to her phenotype. So, the correct answer is: B. phenotype.

Key concepts

Genotype

When we talk about genotype, we are referring to an individual's genetic makeup. It is like the blueprint for a person, which is encoded within their DNA. Genotypes consist of hereditary information carried by the genes.

For instance, think of a genotype as a set of instructions hidden within the genes for Brown Hair or Blue Eyes. These instructions do not always result in visible traits, but they dictate potential expressions.

• A person's genotype includes all the genes passed from parents to offspring.
• It does not describe physical characteristics, but it is the source of genetic potential for those characteristics.

Understanding genotype is crucial because, while we cannot "see" it directly, it is what influences much of what we do see in a person.

Observable Characteristics

Observable characteristics refer to the features of an individual that can be seen or measured. These are aspects like eye color, height, and hair color—exactly what was used to describe Jenny in the exercise.

These characteristics make up what we call the phenotype, which is the expression of the genotype.

• Observable refers to what can be noticed by others, an essential part of understanding phenotypes.
• Such traits are not necessarily passed genetically, as the environment can also play a significant role in some characteristics.

In essence, observable characteristics are the practical, everyday expressions of a person’s genetic potential.

Physical Expression

Physical expression is directly linked to the observable characteristics of an individual. It is about how the genotype gets transformed into visible traits that we can perceive.

The phenotype results from both the expression of the genotype and environmental influences. For example, a person might have a genetic predisposition (genotype) for an athletic build, but without proper nutrition and exercise, the physical expression might vary.

• Physical expression encompasses anything expressed externally from the genetic code.
• It bridges the invisible world of genes with the visible world of traits and characteristics.

Being aware of this helps understand that both genetic makeup and lifestyle affect how characteristics become manifest in individuals.

Traits

Traits are specific characteristics or features that can be passed from one generation to another. They are determined by both genotype and environment. Some common examples of traits are eye color, height, and even behavioral tendencies.

Traits can be categorized into different types:

• Physical Traits: These are observable aspects like hair color, skin color, or height.
• Behavioral Traits: These involve patterns of actions or tendencies, which aren't always visible.

Analyzing traits allows scientists to trace hereditary patterns or identify the impact of environmental factors on an individual’s development. Understanding traits offers significant insight into how complex life forms, like humans, adapt and evolve over time.