Classification of Eggs in Animals The animal eggs are classified according to the following criteria- Amount of yolk, Distribution of yolk, Presence or absence of shell and Type of development. According to the amount of yolk Alecithal: Yolk is absent. If present, it is in a negligible quantity. E.g. Mammals. Microlecithal: The eggs containing small amount of yolk and […]
Comparison between spermatogenesis and oogenesis Spermiogenesis Oogenesis Occurs in germinal epithelium of testes. Occurs in germinal epithelium of ovary. It involves 3 phases namely multiplication, growth and maturation phases. It involves 3 phases namely multiplication, growth and maturation phases. Meiotic divisions are equal. Meiotic divisions are unequal. At the end of the II meiotic division
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Oogenesis in animals is the process by which the female gamete or ova is produced.
The development of sperm in the testes is called spermatogenesis. The testis is a glandular organ composed of several coiled seminiferous tubules and their wall is formed by a multi-layered epithelium called germinal epithelium.
Gametogenesis in Animals The process by which the gametes are produced is known as gametogenesis. the most important characteristic of every living organism is the ability to reproduce to perpetuate the species. The reproductive cells, which unite to form the new individual, are known as gametes. In all higher vertebrates, the gametes from male are called
General Features of development in animals A multi-cellular begins life as a fertilized egg or zygote. The further development depends on the following processes. Growth Growth occurs by the following three basic mechanisms: An increase in the number of cells — In the early stages of development increase in size by cell proliferation is a
Developmental biology is the study of post-natal processes such as normal growth, metamorphosis, regeneration and tissue repair at the levels of complexity ranging from the molecular to the organism level along with the embryonic development.
Composition of Blood in animals Blood is composed of fluid in which the cells and cell fragments are suspended. The fluid portion is known as the plasma‚ and the suspended cellular elements are the – Erythrocytes (RBCs), Leukocytes (WBCs) and Thrombocytes (platelets). Plasma constitutes about 55 to 70% of the blood volume, while the cellular components
Functions of Blood in animals Blood is a fluid connective tissue that flows all over the body in the vessels of the cardiovascular system. functions of blood in animals is described below – Transportation Transport oxygen from lungs to tissues and carbon dioxide from tissues to lungs Transport nutrients from GI tract to liver and other
Adrenal gland of Animals Adrenal gland of The adrenals gland are two small, flattened, reddish brown, ductless glands situated in the roof of the abdomen in Ox. They are elongated from before backwards and flattened from side to side. The right adrenal lies against the medial part of the cranial pole of the right kidney.
