DEVELOPMENTAL BIOLOGY Flashcards
TARGET GRADE MO IS 4O POINTS (OR BEYOND)
All multicellular organisms arise by a
slow process of progressive change
called
Development
Is a process by which a
multicellular organism arises,
initially from a single cell- the
fertilized egg, which
divides mitotically to produce all the
cells of the body.
Development
Fertilized egg
Zygote
The study of animal development ,from that stage of an organism that
exists between fertilization and birth.
Embryology
Observational biology
Embryology
Is the field of science that explores the
potential of an unorganized fertilized cell to form a definite adult
animal
Developmental biology
Development accomplishes two major objectives
It generates cellular diversity and order within each
generation.
It ensures the continuity of life from one generation
to the next.
Fertilized egg becomes an adult through a series of
Non-equivalent cell divisions
Create different cell types each achieving different fates.
Non-equivalent cell divisions
By the end of development we have skin cells, nerve cells, muscle cells, and many other cells types each having different fates. We call these cell types as
Specialized cells
Are the result of differential inheritance of cytoplasm by two daughter cells during mitosis.
Lineage differences
Are the result of two daughter cells occupying different cellular environments and receiving different types of signals from that environment.
Positional differences
Is the process by which new tissue is created from specialized, pre-programmed adult tissue.
Regeneration
Is the process by which cells acquire different fates as a result of differences in the expression of a constant genome.
Differentiation
Formation and
maintenance of pluripotent, haploid
germ cells (gametes)
Gametogenesis
Credited with 1st notions on embryology
Aristotle
Hypothesized that all animals originate from an egg
William Harvey
Drew 1st micrographs of developing chick embryos ; ignited debate between preformationist and epigenesists
Marconi Malpighi
After approximately
forty or ninety days, the fetus
appears as
Formatus
Embryonic structures are
preformed within the gamete
(either egg or sperm)
Preformation
What did Malphigi found?
embryonic structures in “unincubated”
eggs ; the eggs were left in the warm sun of southern Italy during summer months, so although unincubated they were not unfertilized and some embryonic development occured
The embryonic structures
arise anew from the interaction
of substances within the
gametes
Epigenesis
Visualized epigenesis of embryonic germ layers
Christian Pander
Described notochord, discovered mammalian egg and proposed 4 laws of development
Karl Ernst von Baer
