GO IN DEPTH

What Happens in the First Nine Months?

What You Need

 
What Happens in the First Nine Months?

Purpose

To familiarize students with the stages of human development during pregnancy.


Context

The following statement, written by Samuel T. Coleridge, ties in well with the study of human development to which students are introduced during these grades: "The history of man for the nine months preceding his birth would probably be far more interesting, and contain events of greater moment, than all the three score and ten years that follow it."

The human baby develops so dramatically from the time an egg is fertilized to the time a baby is born that one lesson cannot begin to encompass all that happens to a developing fetus during that time. However, this lesson will enhance students' studies by providing them with the chance to explore human development using Internet resources that contain text, drawings, photos, and video about human development.

There are actually several sites on the Internet that show the stages of human development. Many of these sites, though, are geared to pregnant women and their spouses and they are commercial. Still, some of these sites are worth looking at because they not only provide textual information about human development, but they provide drawing, photos, and video that can enrich students' learning about this subject.

This lesson would be most appropriate for students in grades seven and eight. As you present this lesson, you should be aware that although students know that babies result from the fusion of sperm and eggs by the end of the fifth grade, they often do not understand how this fusion brings new life. Some may believe that the baby exists in the sperm but requires the egg for food and protection. Conversely, some may believe that the baby exists in the egg and needs the sperm as a trigger for growth.

Please note that this lesson does not attempt to address the last sentence of the benchmark, which deals with how patterns of human development are similar to those of other vertebrates.


Motivation

Have students use their First Nine Months student esheet to view the Basic Embryology Review Program: Overview Movie presented by the University of Pennsylvania Health System.

The movie lasts less than a minute but it quickly shows the development of a human child from conception to its state at nine months. Have students view the movie twice.

After the first viewing, ask if the development of a human fetus presented in this movie is different from what they believed happened to a fetus during pregnancy. If it is different, ask them to explain what they thought took place.

As students watch the movie a second time, ask them to consider the following and record their thoughts in their science journal:

  • What appears to happen almost immediately after fertilization of the egg?
  • What happens to the appearance of the fertilized egg as it develops?
  • What parts of the body seem to develop first?
  • What does the fetus look like in the early stages of development?
  • At what point in the movie do you first recognize the fetus as being human?

Development

Divide students into small groups. Have students use their student esheet to visit Fetal Development: See how your baby grows on the BabyCenter website. Each group should study a trimester of pregnancy, becoming the class "experts" on its particular set of three months. To do this, each group should make use of the resources available at this site to gather information about human development. Students should be sure to take notes about their research in their science journals.

To help guide students in their research, you might want to post these questions on the blackboard:

  • What body features, if any, have formed during the three months you are studying?
  • What is happening to the cells of the fetus?
  • What organs, if any, have formed?
  • How long is the fetus? How much does the fetus weigh?
  • What senses, if any, have developed?

Once students have completed their research, they should use what they have learned to create drawings to show what is happening to the fetus during the three months for which they are responsible and also point out the developmental milestones that the fetus reaches during this time. Students may want to use rulers to help them depict the amount of growth a fetus goes through from one month of age (at 1/10th of an inch) to its size at nine months (19-22 inches).

Ask each group of students to present its findings to the rest of the class. Be sure to remind the groups to take notes on their classmates' presentations in their science journals.

After the group presenting the first three months has made its presentation, ask students these questions:

  • What body features, if any, have formed during the first three months?
  • What organs, if any, have formed?
  • How long is the fetus? How much does the fetus weigh?
  • What senses, if any, have developed?
  • Are there any features the fetus possesses at the end of the first three months that would lead you to believe that it is a human fetus?

Now have the second trimester group make its presentation and follow-up with these questions:

  • What body features, if any, have formed during the second three months?
  • What organs, if any, have formed?
  • How long is the fetus? How much does the fetus weigh?
  • What senses, if any, have developed?

Finally, have the third trimester group make its presentation to the class. After the presentation, ask students these questions:

  • What body features, if any, have formed during the last three months?
  • What organs, if any, have formed?
  • How long is the fetus? How much does the fetus weigh?
  • What senses, if any, have developed?
  • What activities does the fetus engage in that he/she might continue to do once he/she is born?

Based on students' responses to the questions for each of these sections, you may have to spend more time discussing what they have learned about fetal development during each of the trimesters. Use these questions as a way to gauge what students understand about fetal development.


Assessment

Have each student create a timeline featuring the nine months of pregnancy, dividing the timeline into three sections (for the three trimesters of pregnancy). Instruct them to list the major developments that occur during each of the trimesters, using the knowledge they have gained during this lesson. Students should draw diagrams if they feel it will help them with their explanations. Have students share their work with the rest of the class.


Extensions

Have students visit the NOVA Online site, Odyssey of Life. Once at the site, students can view a time-lapsed video of a human embryo developing in a womb. To see this video, students should click on the word "Morphing" on the Odyssey of Life homepage. Students also can view videos of a pig embryo, a chicken embryo, and a fish embryo.


The Exploratorium's online exhibit called Which embryo is human? offers students more photos of embryos of different vertebrates as well as some explanation for the similarities and differences between them.


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Lesson Details

Grades Themes Project 2061 Benchmarks National Science Standards
AAAS