2019

Name: Date:

Student Exploration: Embryo Development

Vocabulary: Blastula, Carnegie stages, differentiation, ectoderm, embryo, embryology,

embryonic stem cells, endoderm, fetus, gastrula, inner cell mass, mesoderm, morula, neurula,

primitive streak, trilaminar disk, zygote

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1. The images below show embryos of different species at different stages of development.

Label the images below with 1-4 from least developed to most developed.

A 4 B 2 C 3 D 1

2. Which image above do you think is a human? Explain. 3 because it has not only a tail, but a

head forming and little nubs where limbs could form.

Gizmo Warm-up

Embryology is the study of the development of embryos from a

single cell to a multicellular fetus. In the Embryo Development

Gizmo, you will compare the development of different animals

and learn the details of mammalian development. To begin, be

sure the COMPARE tab is selected.

1. What do the images have in common? They are all single cells.

Click on the check box to turn on Scale bars and labels. You are observing the zygotes, or

fertilized single cells, of five animals.

2. At this point, are you able to tell which animal is which? No. Explain. Some of the cells, like

the human and mouse, look similar, but you cannot tell it a mouse cell.

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2019

Activity A:

Comparative

embryology

Get the Gizmo ready:

 Make sure the COMPARE tab is selected and the

Developmental stage slider is on stage 1.

 Turn off Scale bars and labels.

Introduction: Comparative embryology compares embryos of different species to gain insight

into how they are related. To provide a framework for this comparison, embryologists divide this

process into 23 Carnegie stages. You will look at seven of these stages in this activity.

Question: Can we use comparative embryology to determine the relatedness of species?

1. Challenge: Drag the labels to the embryos you think they belong to. Fill in the first row of the

table below with your guesses. Then, move the Developmental stage slider one position to

the right, to Carnegie stage 4. Rearrange your labels if necessary and fill in the next row of

the table. Continue until you get to stage 23. Don’t turn on the Reveal answers check box

until the end. (Note: Your guesses may change as you go through the stages. Don’t worry,

they won’t be graded - this is just for fun!)

Stage A B C D E

1 fish chicken human mouse frog

4 fish chicken human mouse frog

8 frog chicken human mouse fish

13 frog chicken mouse human fish

16 frog chicken mouse human fish

20 frog chicken mouse human fish

23 frog chicken mouse human fish

2. Reveal: Click Reveal answers.

A. Did you guess correctly in the end? Yes

B. At which stage were you able to tell which was which? 13

Explain: At Stage 13, the body shape begins to form and become clear.

3. Observe: Drag the Developmental stage slider back to stage 8. Turn on Scale bars and

labels. What structure does all of the embryos have in common? The neutral groove

becomes visible.

The neural groove will fold into a neural tube and will become the central nervous system.

(Activity A continued on next page)

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https://www.qwivy.com/file/62810691/EmbryoDevelopment-VirtualLabdocx/

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