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BIO310: Developmental Biology

Unit 4: Gastrulation   Once the embryo has become multicellular, it must begin to organize itself and develop germ layers, which are cell layers that will have very different fates and functions as the embryo develops.  These germ layers must also be rearranged to allow for appropriate cell interactions and to ensure that their positions will correspond with the areas where the tissues and organs that they will give rise to will form.  This process involves many cell movements, and, as with cleavage, although many of the movements are shared among different species, the process of gastrulation itself differs in different kinds of embryos.

Unit4 Learning Outcomes
Upon successful completion of this unit, students will be able to:

  • Identify the types of cell movements involved in gastrulation.
  • Demonstrate an understanding the steps of the gastrulation process and what effect the presence or absence of specific molecules and structures have on that process.
  • Distinguish between germ layers and demonstrate an understanding of what tissues/organs develop from each layer.

4.1 Cell Movements   - Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “An Introduction to Early Development” Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “An Introduction to Early Development” (HTML)
 
Instructions: Read the subsection on “Gastrulation” in its entirety, along with Figure 8.6.  This will cover the material in 4.1.
 
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  • Web Media: The Society for Developmental Biology’s Developmental Biology Cinema: Thom Kaufman's “FLY MORPH-O-GENESIS” Link: The Society for Developmental Biology’s Developmental Biology Cinema: Thom Kaufman's “FLY MORPH-O-GENESIS” (HTML, QuickTime)
     
    Instructions: Watch this short video on fly gastrulation; the lateral-side view will probably be the most helpful, but feel free to watch the process from more than one perspective if you wish.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.1.1 Invagination   4.1.2 Involution   4.1.3 Ingression   4.1.4 Delamination   4.1.5 Epiboly   4.2 Germ Layers   Note: The three types of germ layers listed in this subunit are in order from the outermost layer to the innermost layer.  Please note that some groups of organisms, such as sponges and cnidarians (jellyfish, anemones, and corals) have only two germ layers, the ectoderm and endoderm, and are referred to as “diploblastic;” those with three germ layers are referred to as “triploblastic.”

  • Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Germ Layers” Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Germ Layers” (HTML)
     
    Instructions: Read this figure on germ layers and the tissues/organs they form. This will cover the material in 4.2.
     
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4.2.1 Ectoderm   4.2.2 Mesoderm   4.2.3 Endoderm   4.3 Gastrulation in Major Groups of Organisms   4.3.1 Amphibians   - Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Amphibian Development” Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Amphibian Development” (HTML)
 
Instructions: Read all of the subsection on “Gastrulation,” along with associated figures (Figs. 10.5-10.15).
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: DNATube: Jeremy and Julianne Pickett-Heaps’ “Embryonic Origin of Tissues” Link: DNATube: Jeremy and Julianne Pickett-Heaps’ “Embryonic Origin of Tissues” (Adobe Flash)
     
    Instructions: Watch this short (1 minute) video showing the process of amphibian gastrulation and detailing the fate of germ layers.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.3.2 Sea Urchins   - Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Early Development of Sea Urchins” Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Early Development of Sea Urchins” (HTML)
 
Instructions: Read all of the subsection on “Gastrulation,” along with associated figures (Figs. 8.16-8.25).
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.3.3 Birds   - Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Development in Birds” Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Development in Birds” (HTML)
 
Instructions: Read all of the subsection on “Gastrulation,” along with associated figures (Figs. 11.10-11.12).
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.3.4 Mammals   - Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Mammalian Development” Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Mammalian Development” (HTML)
 
Instructions: Read all of the subsection on “Gastrulation,” along with associated figures (Figs. 11.26-11.31).
 
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

  • Web Media: Cold Spring Harbor Press’s “Gastrulation: From Cells to Embryo” Link: Cold Spring Harbor Press’s “Gastrulation: From Cells to Embryo” (HTML, additional, optional files in PDF or Quicktime)
     
    Instructions: This resource is optional.  If you like, browse this site for information, images, and time-lapse movie footage of gastrulation in a wide variety of organisms.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.