About 2200 years ago, Aristotle identified five human senses — sight, hearing, smell, taste and touch. Zoologists have identified many more senses in animals, some of which are given below:…
The brain of reptiles, birds, and mammals is connected to twelve pairs of cranial nerves. Out of these spinal accessory and hypoglossal (XI and XII) are' not present in fishes.…
Hindbrain (Parts and Function) The hindbrain has three parts: medulla oblongata; cerebellum; and pons. The medulla oblongata, also called medulla or myelencephalon, is an enlargement where the spinal cord enters…
THE PSEUDOCOELOMATE BODY : ASCHELMINTHE EVOLUTIONARY PERSPECTIVE (askos, bladder + helmins, worm) The group Aschelminthes has seven different phyla. They are very diverse animals. They have unclear phylogenetic affinities very…
The brain of the developing embryo first becomes apparent as an enlargement of the anterior end of the neural tube. As the brain enlarges, it differentiates into three portions: the…
OBJECTIVES Multiple Choice Questions MCQs 1. Number of speeies of Phylum Platyhelminthes are: (a) 10,000 (b) 15,000 (c) 20,000 (d) 25,000 2. Parenchyma is derived from: (a) Ectoderm (b) Mesoderm …
The extremely complex nervous system of vertebrates is divided into two main divisions - the central nervous system (CNS), composed of brain and spinal cord is site of information processing;…
SUBJECTIVE QUESTIONS Give evolution of Platyhelminthes, Nemertea, and Gastrotricha. Give general characteristics of phylum Platyhelminthes. Describe classification of Phylum Platyhelminthes. Write note on body wall of turbellarians. Write note on…
DEFINITIONS AND KEY POINTS FOR OBJECTIVES TERMS DEFINITIONS Paedomorphosis Sexual maturity in a larval body form is called paedomorphosis. Zooids The two (or more) animals formed as a result of…
FURTHER PHYLOGENETIC CONSIDERATIONS There are different views about the evolution of platyhelminthes: Zoologists believe that the platyhelminthes body form is central to animal evolution. They believe that an ancestral flatworm…
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