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.
This study source was downloaded by 100000835361505 from CourseHero.com on 02-02-2022 15:29:18 GMT -06:00
2019
, Get the Gizmo ready:
Activity A:
Make sure the COMPARE tab is selected and the
Comparative
Developmental stage slider is on stage 1.
embryology
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)
This study source was downloaded by 100000835361505 from CourseHero.com on 02-02-2022 15:29:18 GMT -06:00
2019
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