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Ch. 27 Reproduction and Embryonic Development
Taylor - Campbell Biology: Concepts & Connections 10th Edition
Taylor, Simon, Dickey, Hogan10th EditionCampbell Biology: Concepts & ConnectionsISBN: 9780136538783Not the one you use?Change textbook
All textbooksTaylor, Simon, Dickey, Hogan 10th EditionCh. 27 Reproduction and Embryonic DevelopmentProblem 17
Chapter 27, Problem 17

As a frog embryo develops, the neural tube forms from ectoderm along what will be the frog's back, directly above the notochord. To study this process, a researcher extracted a bit of notochord tissue and inserted it under the ectoderm where the frog's belly would normally develop. What can the researcher hope to learn from this experiment? Predict the possible outcomes. What experimental control would you suggest?

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Understand the role of the notochord: The notochord is a rod-like structure that plays a crucial role in the development of the central nervous system in vertebrate embryos, including frogs. It signals the overlying ectoderm to thicken and form the neural tube, which eventually develops into the brain and spinal cord.
Predict the outcomes of the experiment: By transplanting notochord tissue to a different location (under the ectoderm where the belly develops), the researcher can observe whether the notochord can induce neural tube formation at this new site. This could demonstrate the signaling capability of the notochord and its specificity or flexibility in different embryonic environments.
Consider the implications of the results: If the neural tube forms above the transplanted notochord in the belly region, it suggests that the notochord has the intrinsic ability to induce neural tube formation regardless of its original position. If no neural tube forms, it might indicate that other factors (such as positional information or additional signals from surrounding tissues) are also necessary.
Suggest an experimental control: To validate the results, a control experiment is essential. One possible control would be to insert a similar-sized piece of tissue that does not have the signaling capabilities of the notochord (such as a piece of epidermal tissue) under the ectoderm in the belly region. This would help determine if the changes observed are specifically due to the notochord tissue and not due to the surgery or other disturbances.
Analyze and interpret the data: After conducting the experiment and control, the researcher should compare the outcomes to see if neural tube formation occurs only in the presence of the notochord tissue. This comparison will help in understanding the role of the notochord in neural development and potentially reveal new insights into embryonic signaling mechanisms.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Neural Tube Formation

The neural tube is a structure that forms during embryonic development and eventually develops into the central nervous system, including the brain and spinal cord. It originates from the ectoderm, the outermost layer of the embryo, and its formation is crucial for proper neural development. Understanding how the neural tube forms and the factors influencing its development is essential for predicting outcomes in experiments involving embryonic tissues.
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Notochord Function

The notochord is a rod-like structure that provides support and plays a critical role in the development of the vertebrate embryo. It serves as a signaling center that influences the overlying ectoderm to form the neural tube. By manipulating notochord tissue, researchers can study its role in inducing neural development and how it affects the surrounding tissues, which is central to the experiment described.
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Experimental Controls

Experimental controls are essential components of scientific experiments that help ensure the validity of results. They involve maintaining conditions that isolate the variable being tested, allowing researchers to determine the specific effects of that variable. In this case, a control could involve using ectoderm without notochord tissue to compare the outcomes, helping to clarify the influence of the notochord on neural tube formation.
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