Evolutionary Pressures in Mammals

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EVOLUTIONARY PRESSURES IN MAMMALS Mammals are naturally distributed on all continents except Antarctica. They live in all oceans. EXTERNAL STRUCTURE AND LOCOMOTION SKIN The skin of a mammal consists of epidermal and dermal layers. It protects the animals from mechanical injury, microorganisms, and ultraviolet radiation of sun. Skin also play role in temperature regulation, excretion and water regulation. The skin ...

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Classification of Mammals

CLASSIFICATION OF MAMMALS Class Mammalia Mammary glands: hair: diaphragm: three middle-car ossicles; heterodont dentition;sweat, sebaceous and scent glands: four- chambered heart; large cerebral cortex. (a)     Subclass Prototheria This subclass formerly contained the monotremes. Monotremes have recently been reclassified, and this subclass now contains only extinct species. (b)     Subclass Theria Technical characteristics of the skull distinguish members of this subclass Infraclass: ...

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Diversity of Mammals

DIVERSITY OF MAMMALS Modern mammals have following characteristics: 1. They have hair on the body. 2. They have mammary glands. 3. They have specialized teeth. They have heterodont dentition 4. Three middle-car ossicics are present. 5. Diaphragm is present in them. 6. Their skin has sweat, sebaceous. scent glands. 7. Theirheart is four- chambered. 8. They have large cerebral cortex. ...

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Mammals Evolutionary Perspective

 MAMMALS EVOLUTIONARY PERSPECTIVE Tertiary period started about 70 million years ago. It was the start of the “age of mammals.” It produces adaptive radiation in the mammals. Extinction of many reptilian lineage also occurred in this period. The synapsid lineage of reptiles diverged from other amniote lineages in the Carboniferous period. Synapsid lineage formed the roots of the mammals. 1. ...

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OBJECTIVES OF BIRDS

OBJECTIVES OF BIRDS Multiple Choice Questions MCQs 1. The age of reptiles is: (a) Jurassic period    (b) Tertiary period (c) Secondary period   (d) Triassic period 2. Early synapsids were: (a) pulveosaurs            (b) Therapsids               (c)Parapsids                   (d) None 3. Diastema is present in: (a) Cynodonts              (b) Herbivore                (c) Carnivores                   (d) All 4. Monotremes are placed in: (a) Prototheria          (b) Metatheria          ...

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MULTIPLE CHOICE QUESTIONS AND FILL IN BLANKS OF STRUCTURE OF PLANTS PARTS

plant-parts

MULTIPLE CHOICE QUESTIONS AND FILL IN BLANKS OF STRUCTURE OF PLANTS PARTS 1.  Casparian strips are present in (a) Cortex          (b) Epidermis (c) Stele                (d) Endodermis 2.  The outer most part of the stele consists of one or more layers of parenchymatous cells. The outer layer of this parenchyma is called: (a) Cortex          (b) Epidermis ‘ (c) Stele              (d) pericycle ...

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SHORT QUESTIONS OF STRUCTURE OF PLANT PARTS

SHORT QUESTIONS OF STRUCTURE OF PLANT PARTS 1.  Differentiate between tap and adventitious roots. Ans: Tap root arise from the embryo. Adventitious root develops from other mature tissues of plant like stem etc. 2.  What are root hairs? Give their functions. Ans: A root hair starts its growth as a small papilla on the outer wall. The nucleus and cytoplasm ...

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SUBJECTIVE QUESTIONS OF STRUCTURE OF PLANTS PARTS

SUBJECTIVE QUESTIONS OF STRUCTURE OF PLANTS PARTS 1.  Describe structure of root. 2.  Give secondary growth in root. 3.  Compare monocots and dicot roots 4.  Describe structure of stem. 5.  Compare monocot and dicot stems. 6.  Discuss primary growth in stem. 7.  Discuss secondary growth in stem. 8.  What is periderm? How is it formed? 9.  Describe structure of leaf. ...

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Characteristics of Wood

wood

CHARACTERISTICS OF WOOD Wood is a I–41 fibrous tissue found in many plants. It has been used for centuries ice noth fuel and as a construction material. It is composed of 2 natural composite of cellulose fibers (which are strong in tensio .) embedded in a matrix of lignin. Lignin resists compression. W md is produced as secondary xylem in ...

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