91Ó°ÊÓ

In a hypothetical research situation, scientists discover bacterial endospores in silt at the bottom of a marsh that has been contaminated with a pollutant for 25 years. The silt of the marsh was deposited in annual layers. The age of the endospores can be estimated, then, by identifying the layer of silt in which the endospores are found. In flask A, researchers place 20-year-old endospores along with growth medium and the pollutant. In flask B, researchers place 100-year-old endospores along with growth medium and the pollutant. Explain why you would expect to see more growth in one particular flask than in the other. a. Because endospores formed 20 years ago would be more dormant compared to endospores formed 100 years ago, before the marsh was polluted. b. Because endospores formed 20 years ago would be less adapted to polluted conditions compared to endospores formed 100 years ago, before the marsh was polluted. c. Because endospores formed 20 years ago would be more adapted to polluted conditions compared to endospores formed 100 years ago, before the marsh was polluted. d. Because endospores formed 20 years ago would be less dormant compared to endospores formed 100 years ago, before the marsh was polluted.

Step by step solution

01

Understand the Scenario

Researchers are comparing the growth of bacterial endospores from two different ages, one 20 years old and the other 100 years old, both placed in the same conditions with growth medium and a pollutant.

02

Analyze the Impact of Pollutant and Age

Consider how the pollutant and the age of the endospores might affect their adaptation and dormancy. Endospores formed before the marsh was polluted (100 years ago) have not adapted to the polluted environment, whereas those formed after the pollution (20 years ago) have had time to adapt.

03

Evaluate Dormancy Levels

Think about the dormancy period. Less dormant endospores will be more likely to germinate and grow compared to more dormant ones. Older endospores (100 years old) are likely to be more dormant than younger ones (20 years old).

04

Compare the Adaptation Levels

20-year-old endospores have developed in a polluted environment and are more likely to be adapted to these conditions, unlike 100-year-old endospores, which are less adapted to the current polluted environment.

05

Select the Most Appropriate Explanation

Based on the analysis, endospores from 20 years ago would be better adapted to the current polluted conditions and less dormant compared to the endospores from 100 years ago. This makes option 'c' the most plausible answer: 'Because endospores formed 20 years ago would be more adapted to polluted conditions compared to endospores formed 100 years ago, before the marsh was polluted.'

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

bacterial dormancy

Bacterial dormancy is a state in which bacteria significantly reduce their metabolic activity, allowing them to survive in unfavorable conditions. Think of it as bacteria going into a

environmental adaptation

Environmental adaptation refers to the ability of organisms, including bacteria, to adjust and survive in different environmental conditions. This process is crucial for bacterial survival in changing habitats. A clear example is how bacterial endospores can adapt to polluted environments over time. Endospores formed in polluted conditions (like the 20-year-old ones in the exercise) are more likely to survive and thrive in those conditions compared to endospores formed before the pollution (like the 100-year-old ones). They adapt through mechanisms such as: altering their cellular structures and metabolic pathways to tolerate toxins, undergoing genetic mutations that enhance survival in harmful environments, and developing resistance to pollutants, ensuring their sustainability.
In conclusion, environmental adaptation is essential for the continuation of bacterial life in varying ecosystems.

pollutant impact on microorganisms

Pollutants can have significant impacts on microorganisms. These impacts can be both negative and positive, depending on the microorganism's ability to adapt. Here are some key points:

• Negative Impact: Pollutants can inhibit microbial growth, damage cellular structures, and disrupt metabolic processes. For less adapted bacteria, this can lead to cell death.
• Positive Impact: For microorganisms adapted to pollution, like the 20-year-old endospores in the exercise, pollutants can become a part of their survival mechanism. These microorganisms can utilize pollutants as energy sources, detoxify them, and even thrive in contaminated environments.

Understanding the impact of pollutants on microorganisms helps researchers develop strategies to manage pollution and harness the capabilities of microorganisms for bioremediation.