30 Questions
What is the name of the hollow spherical body formed by a compact heap of cells known as blastula?
Blastocoel
What is the term used to describe the process of formation of two or more layers of cells from the blastoderm during gastrulation?
Invagination
Which germinal layer gives rise to the skin epidermis and the nervous system?
Ectoderm
Which phase of development follows gastrulation in the embryonic development process?
Organogenesis
What is the name of the cavity in the double-walled cup formed during gastrulation?
Archenteron
Which germinal layer forms the alimentary canal and the digestive glands?
Endoderm
What is the major difference between protoplasmic and cellular animal groups?
The aggregation of cells in specialized tissues in cellular organisms
Which level of organization represents animals with specialized tissues but no organs?
Cell-tissue group
What distinguishes metazoans with tissues from those without tissues?
Aggregations of cells associated to perform collective functions
In which level of organization does differentiation of cytoplasm into subcellular structures occur?
Protoplasmic group
What distinguishes protoplasmic organisms from cellular organisms?
"Aggregations of cells concerned with reproduction and nutrition"
"What is one unique characteristic of metazoans at the tissue-organ level of organization?"
"Strong association among aggregations of cells to perform specific functions"
What is the term used to describe cleavage in which the cleavage furrows do not pass completely through the egg?
Partial cleavage
Which type of eggs experience total or holoblastic cleavage?
Eggs with a small concentration of yolk
What structure is formed by the cleavage of a blastodisc?
Blastoderm
What factor plays a significant role in determining the age at which a young animal emerges into the world by hatching?
Quantity of yolk in the egg
What occurs during the phase of development known as cleavage?
Division of a fertilized egg into numerous cells
Which phase precedes the period of cleavage during embryonic development?
Fertilization
What is the term used to describe the cleavage of Amphioxus and eutherian mammals' eggs due to the presence of minute amounts of yolk?
Microlecithal egg cleavage
What effect does evenly distributed yolk have on the cleavage of fertilized eggs?
Slows down division
How does the uneven distribution of yolk in telolecithal eggs impact cleavage planes?
Causes impeded cleavage at vegetal pole
What characterizes the production of blastomeres in eggs with uneven yolk distribution?
Blastomeres are smaller near vegetal pole
Why is cleavage inhibited in the yolky parts of larger eggs with sharp yolk-cytoplasm separation?
Yolk separation hinders cell division in those areas
What is a characteristic outcome of yolk being separated sharply from cytoplasm in larger eggs?
Blastocoel becomes exocentric
At which level of organization are animals with tissues organized into functional units called organs?
Tissue-organ level
Which organism is an example of a cell-tissue grade of organization according to the text?
Volvox
What process leads to the production of the female gamete known as ovum or egg?
Oogenesis
At what stage does meiosis begin in all oocytes in female fetuses?
Before puberty
Which part of Homo sapiens is an example of the organ-system level of organization?
Alimentary canal
What stage do animals reach when their organs work together to perform specific functions?
Organ-system level
Learn about microlecithal egg cleavage, a process where the fertilized egg repeatedly divides to convert large cytoplasm mass into blastomeres. Explore the significance of yolk quantity and yolk gradient in determining the type of cleavage.
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