Question

One scoop of seeds is planted in a plot of farmland with rich soil and adequate rainfall. Another scoop of seeds from the same batch is planted in a backyard with poor soil that is never watered or fertilized. On average, the seeds in the rich soil grow taller than the seeds in the poor soil. The difference between the average height of the plants in the rich soil and that of the plants in the poor soil is best accounted for by ___________. a. genetic factors b. environmental factors c. 30 percent genetics and 70 percent environment d. 70 percent genetics and 30 percent environment

Short answer

b. Environmental factors

Step-by-step solution

Understand the Scenario

In this scenario, seeds from the same batch are planted in two different environments - a plot of farmland with rich soil and adequate rainfall, and a backyard with poor soil that is never watered or fertilized. The average height of the plants in the rich soil is greater than that of the poor soil.

Analyze the Options

Let's analyze each option to determine which best accounts for the difference in average height: a. Genetic factors: Since the seeds are from the same batch, it can be assumed that the genetic factors are constant, and therefore not a primary reason for the differences in average height. b. Environmental factors: The two environments differ significantly, with one having rich soil and adequate rainfall, and the other having poor soil and no water or fertilization. These differences in the environments can greatly impact the growth of the plants. c. 30 percent genetics and 70 percent environment: This option suggests a combination of genetic and environmental factors, but as mentioned earlier, the genetic factors are constant given the seeds are from the same batch. d. 70 percent genetics and 30 percent environment: Similar to option c, this option also suggests a combination of genetic and environmental factors, but we have already established that the genetic factors are constant for both groups of plants.

Choose the Best Option

Based on the analysis, the best option to account for the difference in average height between the plants grown in rich soil and those grown in poor soil is: b. Environmental factors

Key concepts

Genetic Factors

Genetic factors refer to the inherent traits that are passed down from parent organisms to their offspring through genes. In plants, genetic makeup can determine characteristics such as height, leaf size, and color. However, when dealing with seeds from the same batch, the genetic factors are mostly uniform. This means that if you have two sets of seeds from the same parent plants, their potential for growth should be similar under identical conditions.

Genes act like a blueprint for the plant's potential. But, just like a blueprint, the construction depends on the conditions—such as environmental surroundings.

• Genes determine potential attributes.
• In seeds from the same batch, genetic variability is minimal.
• Environmental factors often play a more significant role in such scenarios.

In the given exercise, genetic factors are controlled because both plots use seeds from the same batch. Thus, the differing plant growth in two environments is more about the circumstances they grow in, not their genetic makeup.

Plant Growth

Plant growth is an intriguing combination of genetic potential and environmental influences. In essence, growth measures how a plant increases in size and develops over time. It is facilitated by several factors, including soil nutrients, water, light, and genetic potential.

Here’s why growth might vary:

• Soil Quality: Nutrient-rich soil supports more vigorous growth.
• Water Availability: Essential for photosynthesis and nutrient transport.
• Light: Fuels the process of photosynthesis.

When plants have access to these optimal conditions, they tend to grow to their fullest genetically-determined potential. Conversely, when these conditions are lacking, growth can be stunted.

In this exercise, the seeds planted in rich soil with adequate water grew taller than those in poorer conditions. Despite having the same genetic make-up, their growth was influenced significantly by their environmental conditions. This highlights how responsive plant growth is to the quality of their surroundings.

Soil Quality

Soil quality is a pivotal component in determining the health and growth of plants. Good quality soil is generally rich in nutrients and organic matter, essential for nourishing plants and assisting in their growth cycles.

Several factors contribute to soil quality:

• Nutrient Content: Good soil contains essential nutrients such as nitrogen, phosphorus, and potassium.
• Soil Texture: The physical makeup of soil, influencing water retention and root development.
• Organic Matter: Presence of decomposed plant and animal material contributes to nutrient cycling.

In this exercise, the plot with rich soil offered a hospitable environment for the seeds to thrive, providing them with the resources needed for optimal growth. Contrastingly, seeds placed in poor soil struggled due to lacking these vital elements. Therefore, soil quality can be a decisive factor in the successful growth of plants, even when other factors include adequate water and sunlight.

The lack of nutrients in poor soil illustrates how critical soil quality can be, ultimately directing the potential growth and health of plants.