This document outlines a syllabus for a developmental biology course, covering historical perspectives, fundamental processes of embryogenesis, and stages of development in animals. It includes units on gametogenesis, fertilization, cleavage, cell interactions, and the formation of fetal membranes. The course emphasizes key concepts such as induction, differentiation, and metamorphosis in various species.

1. DEVELOPMENTAL
BIOLOGY
(5th
semester)
Dr Monita Dhiman
Assistant Professor
Department of Zoology
Khalsa College for Women, Ludhiana

3. EMBRYO LOGY
vs
DEVELOPMENTAL
BIOLOGY

4. HISTORICAL REVIEW
ANAXIMANDER (660 B.C.)
EMPEDOCLES
ARISTOTLE
HARVEY and MALPIGHI
GRAAF (1672)
LEEUWENHOEK (1677)
BONNET (1745)
PANDER (1817)
VON BEAR (1827)

5. CLASSICAL THEORIES
PERFORMATIONTHEORY
EPIGENETIC THEORY
BEAR’s LAW
RECAPITULATION THEORY
BIOGENETIC LAW
MOSAIC THEORY
REGULATIVE THEORY
GRADIENT THEORY
SPEMANN’S THEORY OF ORGANIZERS

6. Basic concept of Development
Development is the process by which a complex multicellular
organism arises from a single cell. An overview of developmental
processes include:

7. Stages of Development
Animals show great diversity, weather earthworm or eagle, termite
or beagle but they show same stage of development except some
exceptions.
There are six fundamental processes of embryogenesis
FERTILIZATION
CLEAVAGE
GASTRULATION
ORGANOGENESIS
METAMORPHOSIS
GAMETOGENESIS

8. Fusion of mature sex cells, egg and sperm.
Formation of single cell called ZYGOTE
Series of extremely rapid mitotic divisions and
formation of hollow sphere called BLASTULA
Dramatic movement of cells for extensive cell
rearrangements formation of 3 germ layers.
Cells interaction and rearrangement with
each other to form tissues and organs.
Larval form to adult.
Formation of gametes
FERTILIZATION
CLEAVAGE
GASTRULATION
ORGANOGENESIS
METAMORPHOSIS
GAMETOGENESIS

9. Developmental Hierarchy

10. DEVELOPMENT ZOOLOGY
Syllabus
UNIT
-I
 Gametogenesis with particular reference to differentiation of
spermatozoa. Vitellogenesis, role of follicle/subtesticular cells in
gametogenesis.
 Egg maturation : egg membranes : polarity of egg.
UNIT
-II
 Fertilization, parthenogenesis.
 Cleavage : Types of cleavage patterns depending upon amount
and distribution of yolk and position of spindle.
 Blastula and types of blastula. Fate maps of chick and frog
embryos.

11. Syllabus continue….
UNIT
-III
 Induction: cell to cell interactions: juxtacrine, paracrine, gap
junctions; basic concepts of organizers and inducers and their
role. Determination and differentiation.
 Development up to three germ layers in Herdmania, Amphioxus,
frog, chick and rabbit.
UNIT
-IV
 Foetal membranes, their formation and role.
 Mammalian placenta – its formation, types and functions.
Metamorphosis in Herdmania and Rana (frog)