Basics to get started Flashcards
Differentiation
How do cells become different
from one another and from their precursors?
Morphogenesis
How the ordered form is
generated?
Growth
How is size regulated?
Reproduction
How does one generation create
another generation?
Evolution
How do changes in developmental processes create new anatomical structures?)
Epigenesis
The theory, now generally held, that an embryo develops progressively from an undifferentiated egg cell.
Ectoderm
Gives rise to the epidermis, nervous system, and pigment cells.
Mesoderm
Generates the kidneys, gonads, bones, heart, and blood cells.
Endoderm
Forms the lining of the digestive tube and the respiratory system
Homologous structures
Those organs whose similarity is due to their
sharing a common ancestral structure
Analogous structures
Those organs whose similarity
comes from their serving a similar function (but which are not derived from a common ancestral
structure)
Fertilization
The fusion of genetic material from the two gametes the sperm and the egg
Embryogenesis
The stages of development between fertilization and hatching
Major stages of animal development
Gametogenesis, Fertilization Cleavage Gastrulation Organogenesis Larval Stages Maturity
Cleavage
Series of extremely rapid
mitotic divisions wherein the enormous volume of zygote cytoplasm is divided into numerous
smaller cells. These cells are called blastomeres, and by the end of cleavage, they generally form
a sphere known as a blastula.
Gastrulation
After the rate of mitotic division has slowed down, the blastomeres undergo dramatic
movements wherein they change their positions relative to one another. The embryo is said to be in the gastrula stage. As a result of gastrulation, the embryo contains three germ layers: the ectoderm, the endoderm, and the mesoderm.
Organogenesis
Once the three germ layers are established, the cells interact with one another and rearrange
themselves to produce tissues and organs.
Many organs contain cells from more than one germ layer, and it is not unusual for the outside of an organ to be derived from one layer and the inside from another. For example, the outer layer of skin comes
from the ectoderm, while the inner layer (the dermis) comes from the mesoderm. Also during
organogenesis, certain cells undergo long migrations from their place of origin to their final
location. These migrating cells include the precursors of blood cells, lymph cells, pigment cells,
and gametes. Most of the bones of our face are derived from cells that have migrated ventrally
from the dorsal region of the head.
Germ cells
The gametes and their precursor cells
They are set aside for reproductive function
Somatic cells
All other cells
