15 concise topics with breakdowns: definitions, key facts, and class questions.
Ontogenesis is not simply an increase in size, but a strict sequence of molecular, cellular, and tissue events. In this section, we examine how a complex multicellular organism develops from a single zygote and what laws govern this process.
The material covers everything from the history of embryology to modern reproductive technologies. You will study the properties and cellular mechanisms of ontogenesis, embryonic induction, the law of embryonic resemblance, as well as the mechanisms of growth and morphogenesis.
Colloquia and exams traditionally place a strong emphasis on the genetic control of development. Pay special attention to the genetic mechanisms of cell differentiation and the formation of the spatial organization of the body. Homeotic genes, maternal-effect genes, and zygotic genes are topics that are tested most rigorously and where students most frequently get confused.
What is the essence of the Fundamental Biogenetic Law?
Ontogeny is a brief recapitulation of phylogeny. This means that an organism, during its individual development, passes through stages characteristic of its evolutionary ancestors.
What is developmental genetics and what does it study?
This is the science that studies the realization of hereditary information during individual development. Its primary goal is to trace the pathway from a gene to the formation of a morphological, biochemical, or molecular trait.
What is the difference between Morgan's and Goldschmidt's approaches to differential gene activity?
Morgan believed that regulation occurs at the transcriptional level (differential activity), whereas Goldschmidt hypothesized that regulation takes place at the translational and post-translational levels (differential expression).
How is the adaptive nature of ontogenesis manifested?
It manifests as the polyvariance of individual development, meaning the organism's ability to alter the trajectory of trait formation to adapt to various environmental conditions.
Why do embryonic tissues grow unevenly?
The rate and number of division (proliferation) cycles are genetically predetermined. Varying rates and directions of growth are necessary for the formation of the body's spatial organization and the diversity of organs.
What is the main mechanism of cell differentiation?
In differential gene expression. Cells share the same genotype, but different structural genes are active in them: those required for a specific tissue are activated, while the rest are repressed.
Master the entire topic in the "Biology" course
This is a summary. The course covers everything tested in classes and exams.
3,793 pages of study guides across all topics
Assignments and quizzes after every topic — just like in a colloquium