Developmental biology notes covering gametogenesis, fertilization, cleavage, embryogenesis, morphogenesis, differentiation, organogenesis, stem cells, developmental genetics, and regulation of animal development.
An egg is a biological structure which contains the female gamete and after fertilization it carries the developing embryo. It is an organic vessel that provides protection and nourishment to the embryo till hatching or birth. The major internal component of egg is yolk (vitellin) which acts as reserve food material and supplying energy for … Read more
What is Biogeny (Formation of Primitive Life)? 1. Formation of nucleic acids and nucleoproteins The formation of nucleic acids and nucleoproteins considered as one of the key transition in Biogeny where information molecules begin to store and transmit life instructions. It started after Chemogeny produced small organic monomers like nucleobases, sugars, phosphates, etc. Prebiotic synthesis … Read more
What is cleavage? Characteristics of cleavage Step by step process of Cleavage Types of cleavages The cleavage pattern in embryos mainly determined by yolk quantity and how that yolk is distributed by the cytoplasm.Also, timing and direction of mitotic spindle (inside egg) play important role. Yolk usually slow / restrict the process of complete division. … Read more
What is Regeneration? Definition of Regeneration Regeneration is the natural process by which organisms restore, repair, or replace lost or damaged body parts through the growth and differentiation of specialized cells, often known as stem cells. Types of Regeneration Regeneration, a pivotal biological process, can be classified into distinct types based on the underlying mechanisms … Read more
What is Metamorphosis? Metamorphosis is a biological process characterized by a profound transformation in the form, structure, or physiology of an organism as it progresses through distinct stages of its life cycle. It involves significant changes that are often irreversible and result in the emergence of a new developmental stage or life form. Stages of … Read more
The development of frogs follows a typical sequence of events observed in sexually reproducing organisms. It begins with the fertilization of an egg or zygote. The zygote then undergoes a series of divisions, dividing and re-dividing to form an embryo. The embryo is the earliest stage of development and remains within the egg or reproductive … Read more
What is Chemogeny? 1. Origin of Earth’s Primitive Atmosphere 2. Formation of Simple Inorganic Molecules (Water, Ammonia and Methane) The formation of simple inorganic molecules, such as water, ammonia, and methane, played a significant role in the chemical evolution of the primitive Earth. During the early stages, when the surface temperature of the Earth was less … Read more
What is Stem cell? Classification of Stem Cells Stem cells can be classified into different categories based on their origin, potency, and differentiation potential. Here are the main classifications of stem cells: It’s important to note that the classification of stem cells is not always rigid, as there can be overlap and ongoing research to … Read more
What is Teratogenesis? Teratogenic Agents 1. Infectious agents 2. Physical agents 3. Chemical agents Chemical agents, including certain medications and substances, can have teratogenic effects on the developing fetus. These agents can disrupt normal development and contribute to the occurrence of birth defects. Here are some key points about different chemical agents and their teratogenic … Read more
What is Ageing? Different Types of Aging Aging is a complex process that can be categorized into different types based on various perspectives. Understanding these different types of aging can provide a comprehensive view of the aging process. Here are five common classifications: Overall, aging is a multifaceted process that encompasses various dimensions. By considering … Read more
