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Course Question & AnswerDevelopmental Biology
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In order to take this course you must:
√ Have access to a computer.
√ Have continuous broadband Internet access.
√ Have the ability/permission to install plug-ins or software (e.g., Adobe Reader or Flash).
√ Have the ability to download and save files and documents to a computer.
√ Have the ability to open Microsoft files and documents (.doc, .ppt,.xls, etc.).
√ Be competent in the English language.
√ Have read the Saylor Student Handbook.Unit Outline show close
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Unit 1: Beginnings
This unit will introduce you to the field of developmental biology, including some of its most fundamental preoccupations, its early history, and our current understanding of the beginning of development itself: gametogenesis and fertilization.
Unit 1 Learning Outcomes show close
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1.1 Introduction to Developmental Biology
- Lecture: Professor Hazel Sive’s “Steps in Development”
Link: MIT: Professor Hazel Sive’s “Steps in Development” (YouTube)
Also available in:
Transcript (HTML)
Transcript (PDF)
iTunes U
Instructions: Watch Lecture 19 (“Steps in Development”); although the details of developmental processes will be unfamiliar to you until later in this course, this lecture will provide you with a good overview of the field of developmental biology and the areas of study within it. This lecture will cover the entirety of Unit 1.
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- Lecture: Professor Hazel Sive’s “Steps in Development”
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1.1.1 Origins and History
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Comparative Embryology”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Comparative Embryology” (HTML)
Instructions: Read the introduction to the section on Comparative Embryology and the section “Epigenesis and Preformation.” These readings will cover the material in 1.1.1-1.1.2.
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Comparative Embryology”
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1.1.2 Early Beliefs
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Sperm”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Sperm” (HTML)
Instructions: Read the first four paragraphs of this section (up to but not including the second website link).
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Sperm”
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1.1.3 Basic Questions
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Questions of Developmental Biology”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Questions of Developmental Biology” (HTML)
Instructions: Read this section in its entirety.
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Questions of Developmental Biology”
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1.1.4 Research Approaches
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Comparative Embryology”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Comparative Embryology” (HTML)
Instructions: Read from the section “Naming the Parts” through the end of this section. Make sure to view all associated figures (Figs. 1.3-1.11).
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Comparative Embryology”
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1.2 Gametogenesis
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Structure of the Gametes”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Structure of the Gametes” (HTML)
Instructions: Read from the fifth paragraph of the sub-section on “Sperm” through the end of this section, reading all of the section on “The Egg” and all associated figures (Figs. 7.2.-7.19).
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Structure of the Gametes”
- 1.2.1 Isogamy and Anisogamy
- 1.2.2 Spermatogenesis vs. Oogenesis
- 1.3 Fertilization
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1.3.1 Sperm and Egg Recognition
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Recognition of Egg and Sperm”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Recognition of Egg and Sperm” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 7.8-7.18). This will cover the materials in 1.3.1-1.3.2.
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Recognition of Egg and Sperm”
- 1.3.2 Sperm and Egg Binding
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1.3.3 Membrane and Pronuclear Fusion
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Gamete Fusion and the Prevention of Polyspermy”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Gamete Fusion and the Prevention of Polyspermy” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 7.20-7.26). This will cover the materials in 1.3.3-1.3.4.
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Gamete Fusion and the Prevention of Polyspermy”
- 1.3.4 Mechanisms of Preventing Polyspermy
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1.3.5 Fertilized-Egg Activation
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Activation of Egg Metabolism”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Activation of Egg Metabolism” (HTML)
Instructions: Read the introduction to this section as well as “Early Responses” and “Late Responses,” along with all associated figures (Figs. 7.1-7.30). Do not read the grey text box on “The Activation of Gamete Metabolism.”
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- Reading: The Society for Developmental Biology’s Developmental Biology Cinema: Dr. Lionel Jaffe's “Calcium Tsunami”
Link: The Society for Developmental Biology’s Developmental Biology Cinema: Dr. Lionel Jaffe's “Calcium Tsunami” (HTML, Quicktime)
Instructions: Watch this brief video of a fish egg’s calcium “wave” that blocks polyspermy and activates egg metabolism.
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Activation of Egg Metabolism”
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Unit 2: Genes and Development
Before you continue to follow the process of development in a newly fertilized egg, it is important to learn about another fundamental aspect of development: the role that genes play in determining cells’ behaviors and fates. After all, every cell has the same genes as any other cell; how, then, do these cells differentiate and lead to the development of entirely different, complex structures? The answer is: through differential gene expression. The expression and transmission of genes has been a part of developmental biology from the start. This unit will describe the first discoveries of genetic expression and transmission in embryos, the molecular basis for this regulation of expression, and the current molecular techniques used by developmental biologists to determine what genes are expressed and where.
Unit 2 Learning Outcomes show close
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2.1 Early Evidence for Genes
- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Embryological Origins of the Gene Theory”
Link: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Embryological Origins of the Gene Theory” (HTML)
Instructions: Read this section in its entirety.
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- Reading: National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Embryological Origins of the Gene Theory”
- 2.2 Differential Gene Expression
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2.2.1 Transcription
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Differential Gene Transcription”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Differential Gene Transcription” (HTML)
Instructions: Read all parts of this section except for the subsection on “Locus Control Regions.” You are not responsible for memorizing the extensive examples given in this section (except for the examples of Pax6 and MITF); just understand the basic mechanisms through which transcription is regulated.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Differential Gene Transcription”
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2.2.2 RNA Processing
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Differential RNA Processing”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Differential RNA Processing” ” (HTML)
Instructions: Read this section in its entirety, along with all associated figures (Figs. 5.26-5.29).
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Differential RNA Processing”
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2.2.3 Translation
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Control of Gene Expression at the Level of Translation”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Control of Gene Expression at the Level of Translation” (HTML)
Instructions: Read this section in its entirety, along with all associated figures (Figs. 5.31-5.34).
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Control of Gene Expression at the Level of Translation”
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2.2.4 Post-translational Modifications
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Posttranslational Gene Regulation”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Posttranslational Gene Regulation” (HTML)
Instructions: Read this one-paragraph section.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Posttranslational Gene Regulation”
- 2.3 Molecular Techniques
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2.3.1 RNA Localization
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “RNA Localization Techniques”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “RNA Localization Techniques” (HTML)
Instructions: Read this section in its entirety, along with all associated figures (Figs. 4.14-4.17).
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “RNA Localization Techniques”
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2.3.2 Chimeras
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Determining the Function of Genes during Development”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Determining the Function of Genes during Development” (HTML)
Instructions: Read this section in its entirety, along with all associated figures (Figs. 4.18-4.23). This reading will cover subunits 2.3.2-2.3.4.
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- Web Media: The Society for Developmental Biology’s Developmental Biology Cinema: Nicole Le Douarin's “Quail-Chick Chimeras”
Link: The Society for Developmental Biology’s Developmental Biology Cinema: Nicole Le Douarin's “Quail-Chick Chimeras” (HTML, Quicktime)
Instructions: Watch at least one of these brief videos showing quail-chick chimeras and the processes involved in making them.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Determining the Function of Genes during Development”
- 2.3.3 Genetic Knockouts
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2.3.4 Antisense RNA
Note: As you learn about the genes involved in development, remember that many genes are named for the traits of individuals with their mutations; “wingless,” for example, is not a gene for winglessness, but organisms with defective copies of this gene will have no wings or defective wings. Genes are not named this way in order to confuse students, although it may sometimes seem like it; rather, they are given these names because often the only or best way to determine which genes are necessary for specific aspects of development is to inactivate them and see how the embryo develops in their absence.
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Unit 3: Cleavage
Now that the egg is fertilized, it must still develop from a single cell into a multicellular organism. The first step in this process is extremely rapid cleavage; during this time, the egg undergoes a tremendous amount of cell division without increasing in overall size. All embryos undergo this stage of development, but different types of embryos exhibit very different kinds of cleavage patterns.
Unit 3 Learning Outcomes show close
Also, beginning during cleavage (although this is a process that can continue during much of development), cells’ fates begin to be “specified”—that is, they are committed to forming a particular type of tissue or structure different from other structures. Specification is the first step in the differentiation process that ends with determination, at which point cells’ fates are fixed and cannot be altered based on outside or surrounding influences.
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3.1 Mechanisms of Cleavage
- 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 entirety of the subsection on “Cleavage” along with all associated figures (Figs. 8.1-8.5). This will cover the material in 3.1-3.4.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “An Introduction to Early Development”
- 3.1.1 Mitosis Promoting Factor (MPF)
- 3.1.2 Mechanisms of Mitosis
- 3.2 Cleavage Patterns
- 3.2.1 Poles
- 3.2.2 Yolk
- 3.3 Holoblastic Cleavage: Isolecithal and Mesolecithal
- 3.3.1 Bilateral
- 3.3.2 Spiral
- 3.3.3 Radial
- 3.3.3.1 Isolecithal
- 3.3.3.2 Mesolecithal
- 3.3.4 Rotational
- 3.4 Meroblastic Cleavage: Telolecithal and Centrolecithal
- 3.4.1 Bilateral
- 3.4.2 Discoidal
- 3.4.3 Superficial
- 3.5 Cleavage Patterns in Major Groups of Organisms
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3.5.1 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 “Cleavage,” along with associated figures (Figs. 8.8-8.14), except for the portion on “Axis Specification.”
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Early Development of Sea Urchins”
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3.5.2 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 “Cleavage,” along with associated figures (Figs. 10.1-10.4).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Amphibian Development”
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3.5.3 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 “Cleavage,” along with associated figures (Figs. 11.8-11.9).
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Development in Birds”
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3.5.4 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 “Cleavage,” along with associated figures (Figs. 11.20-11.25).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Mammalian Development”
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3.6 Cell Specification
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Developmental Mechanics of Cell Specification”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Developmental Mechanics of Cell Specification” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 3.7-3.25). This will cover the material in 3.6.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Developmental Mechanics of Cell Specification”
- 3.6.1 Specification vs. Determination
- 3.6.2 Autonomous Specification
- 3.6.3 Conditional Specification
- 3.6.4 Syncytial Specification
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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.
Unit 4 Learning Outcomes show close
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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.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- 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.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “An Introduction to Early Development”
- 4.1.1 Invagination
- 4.1.2 Involution
- 4.1.3 Ingression
- 4.1.4 Delamination
- 4.1.5 Epiboly
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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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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Germ Layers”
- 4.2.1 Ectoderm
- 4.2.2 Mesoderm
- 4.2.3 Endoderm
- 4.3 Gastrulation in Major Groups of Organisms
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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.See a broken link? Please let us know!
- 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.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Amphibian Development”
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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.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Early Development of Sea Urchins”
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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.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Development in Birds”
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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.See a broken link? Please let us know!
- 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.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Mammalian Development”
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Unit 5: Axis Formation
All eggs have essentially radial symmetry, but most animals exhibit at least some bilateral symmetry: differences in their right and left sides, their anterior and posterior ends, as well as their dorsal and ventral surfaces. How are these patterns created? They are the result of a complex series of processes that specify which cells will be in which part of the embryo and that in turn guarantee that the organism’s heart will be in the right place—literally. In this unit, you will focus on axis formation in two model systems: an invertebrate (the fruit-fly, or Drosophila spp.) and a vertebrate (the frog). These organisms have been studied extensively, and the molecular mechanisms of their axis formation are relatively well understood. They will accordingly serve as excellent illustrations of the complex processes involved in this aspect of development.
Unit 5 Learning Outcomes show close
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5.1 Types of Axes
- 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 “Axis Formation” its entirety, along with Figure 8.7. This will cover the material in 5.1.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “An Introduction to Early Development”
- 5.1.1 Dorsal-Ventral
- 5.1.2 Anterior-Posterior
- 5.1.3 Left-Right
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5.2 Axis Formation in Drosophila
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: Drosophila Development and Axis Specification”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: Drosophila Development and Axis Specification” (HTML)
Instructions: Read this summary in its entirety. It will provide a greater overview of the processes addressed in your specific readings for 5.2.1-5.2.2.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: Drosophila Development and Axis Specification”
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5.2.1 The Anterior-Posterior Axis
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Origins of Anterior-Posterior Polarity”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Origins of Anterior-Posterior Polarity” (HTML)
Instructions: Read the introductory paragraph of this section along with Fig. 9.8.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Origins of Anterior-Posterior Polarity”
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5.2.2 The Dorsal-Ventral Axis
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Generation of Dorsal-Ventral Polarity”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Generation of Dorsal-Ventral Polarity” (HTML)
Instructions: Read the introductory paragraph of this section and the subsection “The Morphogenetic Agent for Dorsal-Ventral Polarity” along with Fig. 9.33.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Generation of Dorsal-Ventral Polarity”
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5.3 Axis Formation in Amphibians
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Axis Formation in Amphibians”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Axis Formation in Amphibians” (HTML)
Instructions: Read all of this section, including associated figures, except for the subsection “Snapshot Summary.” This will cover the material in 5.3.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: DNATube: HHMI’s “Spemann’s Organizer”
Link: Web Media: DNATube: HHMI’s “Spemann’s Organizer” (Adobe Flash)
Instructions: Watch this brief (approx. 2 minutes) video about the seminal experiments Spemann and Mangold conducted to learn about the mechanisms of embryonic patterning.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Axis Formation in Amphibians”
- 5.3.1 The Nieuwkoop Center
- 5.3.2 Spemann’s and Mangold’s Experiments: The Organizer
- 5.4 Overview of Axis Formation in Other Major Groups
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5.4.1 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 “Axis Formation,” along with associated figures (Figs. 11.13-11.19).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Development in Birds”
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5.4.2 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 “Anterior-Posterior Axis Formation” and “The Dorsal-Ventral and Left-Right Axes” along with associated figures (Figs. 11.34-11.44).
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Early Mammalian Development”
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Unit 6: Later Embryonic Development
Once germ layers have been formed and patterning has begun, the embryo can begin to develop those complex tissues and organs it will need for adult life. This unit will detail the formation of tissues and organs arising from each of the three germ layers. You will learn that each germ layer gives rise to very specific structures.
Unit 6 Learning Outcomes show close
- 6.1 The Central Nervous System (CNS) and Epidermis
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6.1.1 The Neural Tube
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Neural Tube” and “Differentiation of the Neural Tube”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Neural Tube” (HTML) and “Differentiation of the Neural Tube” (HTML)
Instructions: In “Formation of the Neural Tube,” read only the introductory paragraph and all figures (Figs. 12.3-12.9). Read all of “Differentiation of the Neural Tube,” along with all figures (Figs.12.10-12.14).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Neural Tube” and “Differentiation of the Neural Tube”
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6.1.2 The Neural Crest
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Neural Crest”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Neural Crest” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 13.1-13.10).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Neural Crest”
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6.1.3 The Epidermis
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: CNS and Epidermis”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: CNS and Epidermis” (HTML)
Instructions: Read this section in its entirety.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: CNS and Epidermis”
- 6.2 Mesoderm
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6.2.1 Paraxial Mesoderm
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Paraxial Mesoderm”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Paraxial Mesoderm” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 14.2-14.9).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Paraxial Mesoderm”
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6.2.2 Intermediate Mesoderm
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Intermediate Mesoderm”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Intermediate Mesoderm” (HTML)
Instructions: Read the introductory sentence and the subsection on “Progression of Kidney Types” along with Figure 14.18.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Intermediate Mesoderm”
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6.2.3 Lateral-Plate Mesoderm
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: Lateral Mesoderm and Endoderm” and “Lateral-Plate Mesoderm” and “Endoderm”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: Lateral Mesoderm and Endoderm” (HTML) and “Lateral-Plate Mesoderm” (HTML) and “Endoderm” (HTML)
Instructions: Read all of the “Snapshot Summary” and read all figures (but no other text) associated with “Lateral-Plate Mesoderm” (15.1-15.25) and “Endoderm” (15.26-15.33). This will cover the material in 6.2.3 and 6.3.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Snapshot Summary: Lateral Mesoderm and Endoderm” and “Lateral-Plate Mesoderm” and “Endoderm”
- 6.3 Endoderm
- 6.4 Limb Formation
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6.4.1 The Limb Bud
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Limb Bud”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Limb Bud” (HTML)
Instructions: Read the subsections “Specification of the Limb Fields” and “Induction of the Early Limb Bud” along with all associated figures (Figs. 16.2-16.4). Make sure to read the associated footnotes at the end of the section.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Limb Bud”
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6.4.2 The Proximal-Distal Axis
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Generating the Proximal-Distal Axis of the Limb”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Generating the Proximal-Distal Axis of the Limb” (HTML)
Instructions: Read all of this section, including Figs. 16.8-16.15, except for the grey text box on Hox genes and limb evolution.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Generating the Proximal-Distal Axis of the Limb”
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6.4.3 The Anterior-Posterior Axis
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Specification of the Anterior-Posterior Limb Axis”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Specification of the Anterior-Posterior Limb Axis” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 16.17-16.19).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Specification of the Anterior-Posterior Limb Axis”
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6.4.4 The Dorsal-Ventral Axis
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Generation of the Dorsal-Ventral Axis”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Generation of the Dorsal-Ventral Axis” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Fig. 16.20).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “The Generation of the Dorsal-Ventral Axis”
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6.4.5 Cell Death
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Cell Death and the Formation of Digits and Joints”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Cell Death and the Formation of Digits and Joints” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Fig. 16.22-16.24).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Cell Death and the Formation of Digits and Joints”
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6.4.6 Front Limb vs. Hind Limb Formation
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Limb Bud”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Limb Bud” (HTML)
Instructions: Read the subsection “Specification of Forelimb or Hindlimb” along with all associated figures (Figs. 16.5-16.6).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Formation of the Limb Bud”
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Unit 7: Very Late - And Post Embryonic Development
We have not yet covered one type of development that is extremely important for creating the next generation: the differentiation of sexes and the development of sexual characteristics and organs. This process is known as sex determination, and, depending on the organisms involved, it can be determined or influenced by environmental as well as genetic factors.
Unit 7 Learning Outcomes show close
Although the most dramatic types of development have already occurred in most organisms during their time as embryos, development itself does not necessarily end once organisms are hatched, born, or otherwise recognized as being fully-formed, independent creatures. Some very important changes in physiology and morphology can occur on the way to—or even during—adulthood. These changes include both metamorphosis—one of the most comprehensive reorganizations of tissues and structures possible—and regeneration.
- 7.1 Sex Determination
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7.1.1 Chromosomal Determination
- Reading: Sinauer Associates: Professor Scott Gilbert’s Developmental Biology Companion: “Social Critique of Sex Determination Research”
Link: Sinauer Associates: Professor Scott Gilbert’s Developmental Biology Companion: “Social Critique of Sex Determination Research” (HTML)
Instructions: This reading is optional. Read this brief summary of an article by Eva Eicher and Linda Washburn criticizing the (inaccurate) overemphasis placed on male sexual development as an active event and female sexual development as a passive, “default” state.
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- Reading: Sinauer Associates: Professor Scott Gilbert’s Developmental Biology Companion: “Social Critique of Sex Determination Research”
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7.1.1.1 Invertebrates
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Chromosomal Sex Determination in Drosophila”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Chromosomal Sex Determination in Drosophila” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 17.15-17.19).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Chromosomal Sex Determination in Drosophila”
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7.1.1.2 Mammals
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Chromosomal Sex Determination in Mammals”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Chromosomal Sex Determination in Mammals” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 17.2-17.12).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Chromosomal Sex Determination in Mammals”
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7.1.2 Dosage Compensation
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Transcriptional Regulation of an Entire Chromosome: Dosage Compensation”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Transcriptional Regulation of an Entire Chromosome: Dosage Compensation” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 5.22-5.23).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Transcriptional Regulation of an Entire Chromosome: Dosage Compensation”
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7.1.3 Unusual Sex Determination
Note: A small number of organisms in a variety of different phyla exhibit what we would consider to be uncharacteristic sex development or sexual systems: some species are simultaneous hermaphrodites; some change sex from male to female or female to male or back and forth; some, like peppermint shrimp, change sex from being male to being simultaneous hermaphrodites! The molecular mechanisms and environmental influences behind these developmental changes are not always understood, but these sexual systems, and their potential adaptive benefits, are currently areas of considerable research interest.
- Reading: Sinauer Associates: Professor Scott Gilbert’s Developmental Biology Companion: “Translational Regulation of Germline Sex Determination” and “Normal Hermaphroditism in Nematodes and Fish”
Links: Sinauer Associates: Professor Scott Gilbert’s Developmental Biology Companion: “Translational Regulation of Germline Sex Determination” (HTML) and “Normal Hermaphroditism in Nematodes and Fish” (HTML)
Instructions: Read these articles in their entirety to gain a better understanding of the complicated nature of sex determination and development.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Sinauer Associates: Professor Scott Gilbert’s Developmental Biology Companion: “Translational Regulation of Germline Sex Determination” and “Normal Hermaphroditism in Nematodes and Fish”
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7.1.4 Environmental Sex Determination
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Sex Determination” and “Environmental Regulation of Normal Development”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Sex Determination” (HTML) and “Environmental Regulation of Normal Development” (HTML)
Instructions: Read all of “Environmental Sex Determination,” including Figs. 17.20-17.21. In “Environmental Regulation,” scroll down to read the brief sub-subsection entitled “Environment-Dependent Sex Determination.”
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Sex Determination” and “Environmental Regulation of Normal Development”
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7.2 Metamorphosis
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Metamorphosis”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Metamorphosis” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 18.1-18.24). This reading will cover subunits 7.2.1-7.2.3.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Metamorphosis”
- 7.2.1 Overview and Activation
- 7.2.2 Metamorphosis in Amphibians
- 7.2.3 Metamorphosis in Insects
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7.2.4 Metamorphosis in Marine Invertebrates
- Reading: The Saylor Foundation’s “Metamorphosis in Marine Invertebrates”
Link: The Saylor Foundation’s “Metamorphosis in Marine Invertebrates” (PDF)
Instructions: Please read the entirety of the reading linked above.See a broken link? Please let us know!
- Reading: The Saylor Foundation’s “Metamorphosis in Marine Invertebrates”
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7.3 Regeneration
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Regeneration”
Link: Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Regeneration” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 18.25-18.33).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Web Media: DNATube: HHMI’s “Newt Limb Regeneration”
Link: DNATube: HHMI’s “Newt Limb Regeneration” (Adobe Flash)
Instructions: Watch this brief (approx. 1 minute) video showing and explaining the process of limb regeneration in amphibians.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Regeneration”
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Unit 8: "Evo-Devo": Evolutionary and Developmental Biology
Do all organisms share common ancestors? Why are there so many kinds of organisms? Why are there not more kinds of organisms? Do we have traits in common with other closely related species, or even with very distantly related species? How did dramatic evolutionary changes occur?
Unit 8 Learning Outcomes show close
Developmental biology can help us answer many basic evolutionary questions. In fact, developmental evidence has provided support for Darwin’s theory of evolution and in fact continues to illuminate some of the practical questions involved. The developmental similarities animals share, from the “housekeeping” genes we have in common with fruit-flies to the homologous limb structures we share with all other vertebrates, demonstrate our relatedness. The mechanisms through which developmental changes occur give us an idea of how even minor alterations in gene patterning during development could lead to the expression of very different traits for natural selection to act on. The practical constraints on development explain why there are restrictions on the amount of evolutionary variation that can exist. The combination of insights in evolutionary biology and developmental biology can help us answer questions in both fields.
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8.1 Darwin, Evolution, and Developmental Evidence
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “’Unity of Type’ and ‘Conditions of Existence’”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “’Unity of Type’ and ‘Conditions of Existence’” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 22.1-22.2).
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Web Media: PBS: Nova’s Evolution: “The Zoo of You” and “Guess the Embryo”
Links: PBS: Nova’s Evolution: “The Zoo of You” (HTML) and “Guess the Embryo” (HTML)
Instructions: Go through these interactive sites that demonstrate the ways in which various human traits and developmental processes relate back to our evolutionary ancestors and show the similarities in embryos across phyla. These will cover the material in 8.1-8.3.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “’Unity of Type’ and ‘Conditions of Existence’”
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8.2 HOX Genes
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Hox Genes: Descent with Modification”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Hox Genes: Descent with Modification” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 22.3-22.11). This will cover the material in 8.2.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Hox Genes: Descent with Modification”
- 8.2.1 Changes in Downstream Genes
- 8.2.2 Changes in Expression within Body Segments
- 8.2.3 Changes in Expression between Body Segments
- 8.2.4 Changes in Gene Number
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8.3 Homology
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Homologous Pathways of Development” and “Generating the Proximal-Distal Axis”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Homologous Pathways of Development” (HTML) and “Generating the Proximal-Distal Axis” (HTML)
Instructions: Read all of “Homologous Pathways” along with all associated figures (Figs. 22.12-22.16), and in “Generating the Proximal-Distal Axis,” scroll down to read the grey text box “Hox Genes and the Evolution of the Tetrapod Limb.”
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Homologous Pathways of Development” and “Generating the Proximal-Distal Axis”
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8.4 Modularity
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Modularity: The Prerequisite for Evolution through Development”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Modularity: The Prerequisite for Evolution through Development” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 22.17-22.22). This will cover the material in 8.4.1-8.4.3.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Modularity: The Prerequisite for Evolution through Development”
- 8.4.1 Dissociation
- 8.4.2 Duplication and Divergence
- 8.4.3 Co-option
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8.4.4 Correlated Progression
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Developmental Correlation”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Developmental Correlation” (HTML)
Instructions: Read the subsection on “Correlated Progression.”
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Developmental Correlation”
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8.5 Developmental Constraints
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Developmental Constraints”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Developmental Constraints” (HTML)
Instructions: Read this section in its entirety along with all associated figures (Figs. 22.26-22.27). This will cover the material in 8.5.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Developmental Constraints”
- 8.5.1 Physical
- 8.5.2 Morphogenetic
- 8.5.3 Phyletic
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8.6 Developmental Evolutionary Biology
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “A New Evolutionary Synthesis”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “A New Evolutionary Synthesis” (HTML)
Instructions: Read this section in its entirety.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “A New Evolutionary Synthesis”
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Unit 9: “Eco-Devo”: Environmental Influences on Development
All environments influence development; genes may be the same in two eggs, but differences in their cytoplasmic environments can affect them diversely; variations in temperature can influence the sex of turtles and other reptiles; multifarious environmental conditions can induce faster or slower development or stimulate the development of various adaptive traits. Environmental influences are a natural part of development, but these influences can have normal or disruptive effects on organisms, depending on whether or not the environment itself has been disrupted.
Unit 9 Learning Outcomes show close
In this unit, we will explore both natural and unnatural effects of the environment on development. As with “evo-devo,” this field is an area of current interest as researchers become more involved in integrating biological disciplines and in determining the effects of drugs and pollutants, among other factors, on the development of human and non-human organisms.
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9.1 Environmental Influences: Normal Effects
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Regulation of Normal Development”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Regulation of Normal Development” (HTML)
Instructions: Within this chapter, read the subsections on “Larval Settlement,” “Developmental Symbiosis,” “Seasonality and Sex in Aphids,” “Diapause,” “Phenotypic Plasticity,” and “Predator-Induced Responses.” These will cover the material in 9.1.
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- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Regulation of Normal Development”
- 9.1.1 Complex Life Cycles
- 9.1.1.1 Larval Settlement and Metamorphosis
- 9.1.1.2 Alternate Generations (Sexual/Asexual)
- 9.1.1.3 Diapause
- 9.1.2 Developmental Symbiosis
- 9.1.3 Phenotypic Plasticity
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9.1.4 Predator-Induced Responses
- Reading: Boston University: Professor Karen Warkentin’s “Lab Research”
Link: Boston University: Professor Karen Warkentin’s “Lab Research” (HTML)
Instructions: Read this webpage up to, but not including, the subsection on “Developmental, physiological & life history plasticity: the role of oxygen stress in hatching timing.” This site will give you a sense of the effects of the predators on both hatching time and the timing of metamorphosis.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Boston University: Professor Karen Warkentin’s “Lab Research”
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9.2 Environmental Disruptions: Abnormal Effects
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Disruption of Normal Development”
Link: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Disruption of Normal Development” (HTML)
Instructions: Read all of this section except for the “Snapshot Summary.”
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The National Institutes of Health: Professor Scott Gilbert’s Developmental Biology: “Environmental Disruption of Normal Development”
- 9.2.1 Teratogens
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9.2.2 Endocrine Disruptors
- Reading: Wikipedia’s “Imposex,” Environmental Health News’ “Synopsis of ‘Agriculture Alters Gonadal Form and Function in Bufo marinus,’” US Fish and Wildlife Service’s “Endocrine Disruptors,” and National Geographic’s “Household Pollutants Disrupting Fish Genes”
Links: Wikipedia’s “Imposex,” (HTML) Environmental Health News’ “Synopsis of ‘Agriculture Alters Gonadal Form and Function in Bufo marinus,’” (HTML) US Fish and Wildlife Service’s “Endocrine Disruptors,” (HTML) and National Geographic’s “Household Pollutants Disrupting Fish Genes” (HTML)
Instructions: Read each of these brief pages in their entirety to learn more about the effects of environmental pollutants on the sexual development of a variety of organisms.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Wikipedia’s “Imposex,” Environmental Health News’ “Synopsis of ‘Agriculture Alters Gonadal Form and Function in Bufo marinus,’” US Fish and Wildlife Service’s “Endocrine Disruptors,” and National Geographic’s “Household Pollutants Disrupting Fish Genes”
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Final Exam
- Final Exam: The Saylor Foundation's "BIO310 Final Exam"
Link: The Saylor Foundation's "BIO310 Final Exam"
Instructions: You must be logged into your Saylor Foundation School account in order to access this exam. If you do not yet have an account, you will be able to create one, free of charge, after clicking the link.See a broken link? Please let us know!
- Final Exam: The Saylor Foundation's "BIO310 Final Exam"
