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The Biology of Development Course
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BIOL 303
Prerequisite: BIOL 110 and 112
Course Information
Developmental Biology is the study of the growth and differentiation undergone by an organism in the course of its development from a fertilized egg into an independent living being. It then continues into the periods of infancy through maturity and finally old age. In our course, we will concern ourselves with the very earliest stages of development. We will study the phase of development before metamorphosis in amphibia, before hatching in birds and before birth in mammals. Metamorphosis, hatching and birth are merely landmarks in a continuing process of development.
Biology of Development offers more than the acquisition of new facts or an enlarged vocabulary. It gives an understanding of some of the ways of life itself. We are all interested in our own where from? and where to? The processes by which a frog or chick grows from a fertilized egg are fundamentally the same involved in our own development. In addition the study of embryos casts interesting sidelights on the path followed by evolution. Often a phylogenetically newer structure will make use of some component of the older one during the early phases of development. For example, the major blood vessels supplying and draining the placenta in humans are homologous with those supplying the allantois of birds and some lower mammals. In the human, the allantois remains vestigial, but the allantois blood vessels become incorporated into the phylogenetically new placental circulatory system.
As students continue their study into anatomy, they become enmeshed in a maze of structural details without which, a knowledge of how and why adult conditions arose, leads into blind memorization. Clearly the medical field of obstetrics involves a large measure of "applied" developmental biology and many problems, which confront pediatricians, have their origin in faulty development. Even the problem of malignancy is related to development. Here we have a breakdown of the mechanisms that normally control growth and differentiation. Indeed throughout life there are many developmental issues – think about developing a sense of balance to walk or fly or reaching puberty or issues of aging.
Selection for lecture material - The lecture is concerned with discussions of the "invisible" processes of development. Invisibility is used to refer to those phenomena that take place out of what can normally be viewed under the microscope. Often these processes are dynamic and microscope slides can depict only one instant of a long period of time. Furthermore, the lecture will be concerned with pointing out historical and experimental details impacting on the "story of development." Selection for laboratory material - Two considerations are primary. First, and most important, the form chosen should clearly demonstrate the developmental processes it is chosen to illustrate. Second, its early developmental stages should be well known.
For the early stages of development no one form gives quite enough of a basis. Gametogenic material from a variety of organisms, including humans is generally available and will be utilized. For cleavage and germ layer formation, amphibian material is most useful. The formation of the embryonic body and the establishment of the organs in their simple primordial form can be studied most readily from chick embryos. For the study of the later development of the various organ systems mammalian embryos have the most to offer. We will use pig embryos to demonstrate the mammalian condition.
The study of embryos demands accurate observation. It differs, however, from the study of adult anatomy where the objects studied are relatively constant and not subject to rapid change. During development, structural conditions within the embryo are constantly changing. Each developmental phase presents new conditions and new problems.
Solutions to the problems in any given stage of development depend upon knowledge of the stages which precede it. Therefore, it is necessary to start at the beginning and follow the natural order of the changes which occur. Each stage should be studied not so much for itself as for the evidence it affords of the progress of development. In order to comprehend the developmental significance of a structure one must know not only its relations within the embryo being studied at the time, but also the manner in which it has been derived and the nature of the changes by which it is progressing toward adult conditions.
The outstanding idea to be kept in mind at all times is that the development of an individual is a process and that this process is continuous. Embryos of the age where the establishment of the various organ systems and processes of body formation are being initiated are too small to permit dissection but they can be studied via the microscope usually in extremely thin sections. Sections yield accurate but disjointed information because they allow study of local regions only. For this reason, it is necessary to first study entire embryos (whole mounts). From such preparations it is possible to map out the configuration of the body and the location and extent of the internal organs. The fact that embryos have three dimensions must be kept in mind and by careful focusing the depth at which a structure lies must be determined. Unless the preliminary study of entire embryos is carefully carried out, the study of sections will be futile.
In studying a section from a series it is necessary to determine the location in which it was cut through the embryo. Often, this can be done by comparing it with a whole mount. Probably nothing in the study of developmental biology causes students more difficulty than neglecting to locate sections accurately, with the consequent failure to appreciate the relationships of the structures seen in them. This appreciation can be enhanced by constantly referring to whole mounts. Many details which, in the initial observation of the whole mount were inconspicuous, will become significant in light of the more exact information yielded by the sections. The key to success in the study of young embryos is a correlative study of the whole mounts and the cross sections.
The illustrations in your lab manual are of paramount importance. A three-dimensional concept of the embryo is to be synthesized from a microscopic study. The relations are constantly changing with time. Developmental biology is therefore a four dimensional subject. The illustrations available in the lab manual offer a graphic guide to the processes involved in your studies. Prior to coming to the laboratory you should be familiar with textural descriptions and illustrations for your day's study.
Course
Objectives
To learn about:
- The early studies in developmental biology.
- The general patterns and mechanisms of development in a representative group of vertebrates.
- The role of the genome in the developmental process, especially how molecular regulatory hierarchies control development.
- The relationship between development and evolution.
Electronic
Forms of Communication
In accordance with College policy, I will use your
Texts, Readings, Materials
Lecture:
Gilbert, S. 2006. Dev. Biology. 8th
ed. Sinauer
Lab: Huettner, A. 1949. Fundamentals of Comparative Embryology of the Vertebrates. MacmillanWright, S. 2005. A Photographic Atlas of Developmental Biology. Morton Publishing Co.
NOTE: Bring the lecture text to the lecture as we will refer to the figures. Bring the lab text to the lab so that you can refer to the figures.
Course
Requirements
Examinations, Library
Research – There will be two lecture exams and a cumulative final.
Experiential Component
Each course will include a minimum of five (5) hours of unmonitored appropriate experience outside of the classroom. Students will need to spend extra hours in the lab to finish all the slides.
Attendance
Policy – Students are expected to attend each lecture and
lab.
Grading Policy
Only under unusual circumstances is the course offered on a pass/fail basis. You can expect that A's will be awarded to outstanding students, B's to above-average students, and C's to average students. There will be 2 lecture exams and a cumulative final as well as three lab exams. Each lecture exam will be worth 100 points and the final will count for 200 points. Each lab exam will be worth 100 points. The final course grade will be determined by calculating each student's cumulative score against the maximum of 700 attainable points.
Policy on
Academic Integrity
Students are expected to read and understand
Students with
Disabilities
If you need course adaptation or accommodations because of a documented disability, please make an appointment during my office hours.
Weekly Schedule
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Lecture Sequence - Gilbert |
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Lab Sequence - Huettner |
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1 |
Introduction: chapters 2-6 |
1 |
Introduction: chapter 1. pgs 1, 2, 5-8 |
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2 |
Gametogenesis & Egg Organization: chapters 6-8, 19 |
2 |
Microsurgery: chapter 2. pgs 9-16 |
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3 |
Fertilization: chapters 7, 10 |
3 |
Gametogenesis: Spermatogenesis-chapter 3. pgs 17-38; Oogenesis-chapter 4. pgs 39-52 |
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4 |
Cleavage: chapters 8, 10, 11 |
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Fertilization: chapter 5. pgs 53-62, 63-64
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5 |
Gastrulation: chapters 8, 10, 11 |
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Cleavage: Introduction
chapter 6 pgs 67-71
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6 |
Neurulation
& Ectoderm: chapters 12, 13
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6 |
Amphioxus: chapter 6. pgs 75-76, chapter 7 pgs 93-94, chapter 8. pgs 106-108
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7 |
Exam I |
7 |
Exam I |
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8 |
Mesoderm & Endoderm: chapters 12-15 |
8 |
Amphibian: chapter 6. pgs 77-80, chapter 7. pgs 95-96 chapter 8. pgs 109-115 chapter 9. pgs 129-130, 134-136 chapter 10 pgs 143-170 |
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9 |
Morphogenesis: chapters 6, 8, 13 |
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Exam II |
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10 |
Genome and Development: chapters 4, 5, 8, 10 |
10 |
Avian: chapter 6. pgs 80-83 chapter 7. pgs 96-101 chapter 8. pgs 116-123 chapter 9 pgs 130-142 chapter 11 pgs 171-225 |
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11 |
Determination: chapters 5, 9, 19 |
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Exam III |
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12 |
Induction: chapters 6, 10,
11, 13-15
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12 |
If time permits Mammals: chapter 7 pgs 103-104 chapter 8. 123-124 chapter 12 pgs 227-270 |
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13 |
Maternal & Zygotic Control: chapters 5, 8 |
13 |
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14 |
Exam II |
14 |
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15 |
Spatial Patterns of Gene Expression:
chapters 5, 8, 9, 11, 18
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15 |
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16 |
Limb Development: chapters
16, 18
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16 |
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17 |
Gonad & Sex Development:
chapters 17, 19
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17 |
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18 |
Final Exam
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18 |
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Contact Information
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Dr. Edward Saiff, Professor of Biology Office
G300B |
College Closings Phone Number: 201-236-2902
School Offices: G326 and G300 (Phone 201-684-7734)
Last revised: May 2008