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Chapter 14 Morphology of Flowering Plants Part 1

Chapter 14 Morphology of Flowering Plants Part 1

 

 

 

  Introduction.                                                                                                                                                           

Angiospermic or flowering plants show a great variety of shape, size and form. The size ranges from the minute Wolffia and Lamna (0.1cm) to the tall Eucalyptus (up to 100 metre) and large sized Banyan (Ficus bengalensis). In habit, they range from herbs and shrubs to trees.

Morphology (Gr. Morphos = Form; logos = Study) is the branch of science which deals with the study of form and structure. In botany, it generally means the study of external features, forms and relative positions of different organs on plants.

It is virtually impossible to recognise and know all the flowering plants even for a professional taxonomist.

 

However, a student of botany takes the help of morphology for recognition, identification and classification of plants. Some distinct morphological features are most significant in the study of phytogeography, phylogeny and evolution.

Parts of a flowering plant : Flowering plants consist of a long cylindrical axis which is differentiated into underground root system and an aerial shoot system. The root system consists of root and

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Chapter 13 Plant Kingdom Part 4

Chapter 13 Plant Kingdom Part 4

 

 

  1. Apogamy : The terms apogamy was coined by de Bary (1878). It is defined as formation of sporophyte from a gametophytic cell other than egg without fertilization. It was first observed by Farlow (1874) in Pteris cretica. Thereafter it was observed in several other plants e.g., Lycopodium, Selaginella, Nephrodium, Lastrea, Marsilea etc. The apogamy is of two types, obligate and facultative. If either both of the sex organs are nonfunctional or absent, the apogamy occurring on account of this is said to be obligate. But if a gametophytic cell is induced to form the sporophyte without fertilization, the apogamy is called as facultative or induced.
  2. Apospory : The formation of gametophyte from a sporophytic cell without meiosis is called as apospory. This phenomenon was first observed by Druery (1884) in Athyrium filix-femina. Thereafter it has been established in several pteridophytes. e.g., Pteridium aquilinum, Asplenium, Trichomanes etc. Induced apospory was seen in Pteris species.
  3. Parthenogenesis : Formation of sporophyte from egg without fertilization is called as parthenogenesis. Farmer and Digby (1907) observed that in homosporous, leptosporangiate ferns, apospory was always followed by parthenogenesis. This phenomenon has been observed in several species of Selaginella and Marsilea.
  4. Affinities of pteridophytes : The pteridophytes occupy an intermediate place between bryophytes and spermatophytes. They represent affinities with both the groups.

(i)Similarities with bryophytes

  1. Both have terrestrial mode of life.
  2. Water is indispensable for the process of fertilization.
  3. Male gametes are flagellated.
  4. The structure and ontogeny of sex orga

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Chapter 12 Plant Kingdom Part 3

Chapter 12 Plant Kingdom Part 3

 

 

 

 

 

 

 

 

 

 Pteris, Dryopteris and Pteridium (Fern).                                                                                                         

Systematic position

Kingdom          –        Plantae

Sub kingdom     –        Embryophyta Phylum            –        Tracheophyta

Class               –        Leptosparangiopsida

Order               –        Filicales

Family             –        Polypodiaceae

Genus              –        Pteris, Dryopteris, Pteridium (For Rajasthan PMT & UP CPMT Students Only)

  1. Habitat : Ferns live in moist, cool and shady places. They are perennial and evergreen. Fern Dr

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Chapter 11 Plant Kingdom Part 2

Chapter 11 Plant Kingdom Part 2

 

 

(iv)Rhodophyceae

  1. Plants generally marine.
  2. Forms filamentous to parenchymatous.
  3. Cells showing eukaryotic organization.
  4. Chief pigments – Chlorophyll a, d is present but chlorophyll c is absent; a, b–carotene, lutein, violaxanthin, fucoxanthin, myxoxanthin, g–phycoerythrin, g–phycocyanin and allophycocyanin.
  5. Reserve food – Floridean starch, galactan –SO4 polymers.
  6. No zoospore formation.
  7. Male gametes non-flagellate.
  8. Sexual reproduction by specialized type of oogamy.
  9. Life cycle haplobiontic or diplobiontic.

(v)Myxophyceae (Cyanophyceae)

  1. Plants generally fresh water, a few forms marine.
  2. Forms unicelled to filamentous.
  3. Cells showing prokaryotic organization.
  4. Chief pigments – Chlorophyll a; b-carotene; luteins, myxoxanthin, oscillaxanthin, c-phycocyanin, c-phycoerythrin, allophycocyanin.
  5. Reserve food – Cyanophycean starch (glycogen) and cyanophycin (protein).
  6. No zoospore formation.
  7. No flagellate bodies.
  8. No sexual reproduction.
  1. Green algae as a ancestors of land plants : There are sufficient evidences which suggest that the land plants have originated and evolved from algae. Morphological, cytological and biochemical similarities between the green algae and the land plants suggest that the ancestral algae was green, flat and fleshy with heterotrichous filamentous habit similar to Fritschiella (Smith). The various evidences which suggest algal origin of land plants are :
  1. Presence of similar type of photosynthetic pigments – Chlorophyll a, Chlorophyll b<

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Chapter 10 Plant Kingdom Part 1

Chapter 10 Plant Kingdom Part 1

 

 

 

  • Parasexuality was first discovered in fungi.
  • The members of Ascomycetes caused power mildew of crops.
  • Largest fungus is 'Giant puffball'.

Kingdom plantae.

Kingdom plantae includes green, brown and red algae, liwerworts, mosses, ferns and seed plants with or without flowers. They have the following characters.

  1. Multicellular organisms with walled and frequently vacuolate eukaryotic cells.
  2. They contain photosynthetic pigment in plastids.
  3. Principal mode of nutrition is photosynthesis but number of plants have become absorptive.
  4. Primarily non-motile, living anchored to a substrate.
  5. Structural differentiation leading towards organs of photosynthesis, anchorage and support and in higher forms towards specialised photosynthetic, vascular and covering tissues.
  6. Reproduction is primarily asexual or sexual. The reproductive organs are multicellular.
  7. A multicellular embryo is formed during development from the zygote. Algae lack embryo stage. Life cycle consists of alternating haploid gametophyte and diploid sporophyte generation. This phenomenon is called alternation of generation.
  8. Classification : The plant kingdom thus comprises individuals which are structurally and functionally unlike one another. Subsequently several systems of classification of plant were proposed by taxonomists.

Classification of A.W. Eichler : August Wilhelm Eichler, a Viennese botanist, divided plant kingdom into two subgroups :

 

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Chapter 9 Biological Classification Part 3

Chapter 9 Biological Classification Part 3

 

 

 

  Rhizopus/Mucor.                                                                                                                                                  

Systematic position

Kingdom          –         Plantae Sub kingdom           –        Thallophyta Division            –        Mycota

Sub division      –        Eumycotina Class               –        Zycomycetes

Order               –        Mucorales

Family             –        Mucoraceae

Genus              –        Rhizopus (For UP CPMT Students Only)

Mucor (For MP PMT Students Only)

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Chapter 8 Biological Classification Part 2

Chapter 8 Biological Classification Part 2

 

 

(10)Salient features of classes

  1. Phycomycetes  (Oomycetes/Egg  fungi)  : It is also called lower fungi, mycelium is coenocytic. Hyphal wall may contain chitin or cellulose (e.g., Phytophthora). Asexual reproduction occurs with the help of conidio- sporangia. Under wet conditions they produce zoospores. Under dry conditions, the sporangia directly function as conidia. Zoospores have heterokont flagellation (one smooth, other tinsel). Sexual reproduction is oogamous. It occurs by gametangial contact where male nucleus enters the oogonium through a conjugation tube. The fertilized oogonium forms oospore. e.g., Sapolegnia, Albugo (Cystopus), Phytophthora, Phythium, Sclerospora.
  2. Zygomycetes (Conjugation fungi) : Mycelium is coenocytic. Hyphal wall contains chitin or fungal cellulose.  Motile  stage  is  absent.  Spores  (Sporangiospores/aplanospores)  are  born  inside  sporangia.  Sexual reproduction involve fusion of coenogametes through conjugation (Gametangial copulation). It produces a resting diploid Zygospore. On germination, each zygospore forms a germ sporangium at the tip of a hypha called promycelium e.g., Mucor, Rhizopus.
  3. Ascomycetes (Ascus : sac, mycete : fungus) : These are unicellular as well as multicellular fungi. In the latter, mycelium is septate. The asexual spores formed in chains are called conidia. The spores are formed exogenously, i.e.

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Chapter 7 Biological Classification Part 1

Chapter 7 Biological Classification Part 1

 

  Introduction.                                                                                                                                                          

There are millions of organisms – plants, animals, bacteria and viruses. Each one is different from the other in one way or the other. About more than one million of species of animals and more than half a million species of plants have been studied, described and provided names for identification. Thousands are still unknown and are yet to be identified and described. It is practically impossible to study each and every individual. Also, it is difficult to remember their names, characters and uses. However, biologists have devised techniques for identification, naming and grouping of various organisms.

The art of identifying distinctions among organisms and placing them into groups that reflect their most significant features and relationship is called biological classification. Scientists who study and contribute to the classification of organisms are known as systematists or taxonomists, and their subject is called systematics (Gk. Systema = order of sequence) or taxonomy (Gk. Taxis = arrangement; nomos = law).

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Chapter 6 Cell Cycle and Cell Division

Chapter 6 Cell Cycle and Cell Division

 

 

  Cell  division/Cell reproduction/Cell cycle.                                                                                                  

  1. Introduction : It is the process by which a mature cell divides and forms two nearly equal daughter cells which resemble the parental cell in a number of characters.

"Continuity of life" is an important intrinsic characteristic of living organisms and is achieved through the process of reproduction. The reproduction may be asexual or sexual. Both of these involve the division and replication of cells. Even the growth and development of every living organism depends on the growth and multiplication of its cells.

In unicellular organisms, cell division is the means of reproduction by which the mother cell produces two or more new cells. In multicellular organism also, new individual develop from a single cell. The zygote, by the cell division. Cell division is central to life of all cell and is essential for the perpetuation of the species.

  1. Discovery : Prevost and Dumas (1824) first to study cell division during the cleavage of zygote of frog. Nagelli (1846) first to propose that new cells are formed by the division of pre-existing cells.

Rudolf virchow (1859) propose

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Chapter 6 Cell Cycle and Cell Division

Chapter 6 Cell Cycle and Cell Division

 

 

  Cell  division/Cell reproduction/Cell cycle.                                                                                                  

  1. Introduction : It is the process by which a mature cell divides and forms two nearly equal daughter cells which resemble the parental cell in a number of characters.

"Continuity of life" is an important intrinsic characteristic of living organisms and is achieved through the process of reproduction. The reproduction may be asexual or sexual. Both of these involve the division and replication of cells. Even the growth and development of every living organism depends on the growth and multiplication of its cells.

In unicellular organisms, cell division is the means of reproduction by which the mother cell produces two or more new cells. In multicellular organism also, new individual develop from a single cell. The zygote, by the cell division. Cell division is central to life of all cell and is essential for the perpetuation of the species.

  1. Discovery : Prevost and Dumas (1824) first to study cell division during the cleavage of zygote of frog. Nagelli (1846) first to propose that new cells are formed by the division of pre-existing cells.

Rudolf virchow (1859) propose

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Chapter 5 Biomolecules

Chapter 5 Biomolecules

 

 

 

 Micromolecules .                                                                                                                                                   

  1. Definition : These are molecules of low molecular weight and have higher solubility. These include minerals, water, amino acid, sugars and nucleotides. All molecules or chemicals functional in life activity are called biomolecules.
  2. Elements : They are naturally occuring and they are classified on the basis of their property into metals and non-metals. Again on the basis of presence and requirement in plants and animals, they are grouped into major and minor bioelements. Which are required in large amount are major bioelements e.g. Ca, P, Na, Mg, S, K, N, etc., while those are required in small amount are called minor bioelements e.g. Fe, Cu, Co, Mn, Mo, Zn, I, etc.

On the basis of function, they may be of following types :–

  1. Framework elements : Carbon, oxygen and hydrogen.
  2. Protoplasmic elements : Protein, nucleic acid, lipids, chlorophyll, enzymes, etc.
  3. Balancing elements : Ca, Mg and K. counteract the tox

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Chapter 4 Cell The Unit of Life Part 4

Chapter 4 Cell- The Unit of Life Part 4

 

 

 

  1. Flagella are 1 – 4 per cell where as cilia are infinity in number.
  2. Cilia are smaller and flagella are longer in size, 5 – 10 m m and 150 m m respectively.
  3. Structure : Both cilia flagella are structurally similar and possess similar parts-basal body, rootlets, basal plate and shaft

 

  1. Basal body : These are also termed as blepharoplast (kinetosome) or basal granule. It is present below the plasma membrane in cytoplasm. The structure is similar to centriole made of 9 triplets of microtubules. Out of the 3 fibrils of a triplet first is A which is round and other two B and C are semi-circular. 9 triplets are connected to the centre by spokes. ‘C’ fibrils disappears as it enters into shaft.
  2. Rootlets : Made of microfilament and providing support to the basal body. These are striated fibrillar outgrowths.

 

 

Central microtubule

Outer

microtubules Inner arm Outer arm

Spoke Head Interdoublet

link Subtubule A

Subtubule B


 

 

 

 

 

 

 

 

 

 

 

 

 

Radial spoke


 

Membrane Link

Central

sheath

 

 

 

 

 

 

 

 

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Chapter 3 Cell The Unit of Life Part 3

Chapter 3 Cell- The Unit of Life Part 3

 

 

 

 Lysosomes.                                                                                                                                                             

  1. Definition : Lysosomes are electron microscopic, vesicular structures of the cytoplasm, bounded by a single membrane which are involved in intracellular digestive activities, contains hydrolytic enzymes, so called lysosomes.
  2. Discovery : These were first discovered by a Belgian biochemist, Christian de Duve (1995) in the liver cells and were earlier named pericanalicular dense bodies. Terms Lysosome was given by Novikoff under the study of electron microscope. Maltile (1964) was first to demonstrate their presence in plants, particularly in the fungus neurospora.
  3. Occurrence : These are absent from the prokaryotes but are present in all eukaryotic animal cells except mammalian RBCs. They have been recorded in fungi, euglena, cotton and pea seeds.
  4. Shape : These are generally spherical in shape but are irregular in plant root tip cells.
  5. Size : Size range is 0.2-0.8 mm while size is 0.5 mm (500 nm).
  6. Number : Lysosomes are more in those cells which are involved in intracellular digestive activities e.g., WBCs of blood, histiocytes of

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Chapter 2 Cell The Unit of Life Part 2

Chapter 2 Cell- The Unit of Life Part 2

 

 

 

According to this model, the cell membrane consists of a highly viscous fluid matrix of two layers of phospholipid molecules. These serve as relatively impermeable barrier to the passage of most water soluble molecules. Protein molecules occur in the

 

membrane, but not in continuous layer; Instead, these occur as separate particles asymmetrical arranged in a mosaic pattern.

Some of these are loosely bound at the polar surfaces of lipid layers, called peripheral or extrinsic proteins. Others penetrate deeply into the lipid layer called integral or intrinsic proteins. Some of the


 

 

 

 

 

 

Lipid bilayer


Boundary lipid


 

 

 

Polar end Non-polar end

 

integral proteins penetrate through the phospholipid layers and project on both the


Intrinsic protein

 

surface. These are called trans membrane or tunnel proteins (glycophorins). Singly or in


Lipid


Hydrophobic tail

Hydrophilic head                              Intrinsic protein


 

Extrinsic proteins

 

groups, they function as channels for passage of water ions and other solutes. The channels may have g

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Chapter 1 Cell The Unit of Life Part 1

Chapter 1 Cell The Unit of Life Part 1

 

 

 

 Tools and Technique.                                                                                                                                        

The preparation of the cells or cells parts for their study requires very specialized methods. The search continues for new instruments. So as to provide better understanding of cell structure upto molecular level, the following tools and techniques helped the biologists to know more about the cells.

  1. Microscopy : (Gk. Micros = small ; Skopein = to see) It is practice of using microscopes for the study of finer details of small objects including cells and tissues. Microscope are instruments consisting of lenses (made of glass / Lithium fluoride / electromagnetic lens) which magnify and resolve small objects not visible to unaided eye for the study of their details.
    1. Magnification : Is the power of enlargement, which is the ratio of

Magnification = Size of the image with the instrument

Size of the image with unaided eye

Magnification of a microscope is roughly equal to the multiple of magnifying power of objective lens and

ocular lens (eye piece) e.g., if the magnification power of

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Chapter 26 Biomedical technologies

Chapter 26 Biomedical technologies

 

 

A modern hospital can make use of variety of sophisticated instruments and equipment of accurate diagnosis and treatment of diseases. Three main categories of instruments and equipment used are diagnostic, imaging, and therapeutic.

 Diagnostic Instruments.                                                                                                                                     

(i)Sphygmomanometer

  • Sphygmomanometer, commonly called B.P. Apparatus, is an instrument for measuring blood pressure.
  • This instrument consists of a rubber cuff attached by a rubber tube to a compressible hand pump or bulb.
  • Another tube attaches to the cuff and to a column of mercury or pressure dial marked off in millimeters.
  • Blood pressure is usually taken in the left brachial artery.
  • Blood pressure is recorded by giving the systolic pressure and diastolic pressure expressed as millimeters of mercury (mm Hg).
  • A healthy young adult male has blood pressure reading of about 120/80 (i.e. 120 mm Hg systolic and 80

mm Hg diastolic).

  • The difference between systolic and diastolic pressure is called Pulse pressure.
  • Blood pressure often rises normally w

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Chapter 25 Enzymes

Chapter 25 Enzymes

 

 

 

 

  Introduction and history of cellular enzymes.                                                                                               

Enzymes (Gk. en = in; zyme = yeast) are proteinaceous substances which are capable of catalysing chemical reactions of biological origins without themselves undergoing any change. Enzymes are biocatalysts. An enzyme may be defined as "a protein that enhances the rate of biochemical reactions but does not affect the nature of final product." Like the catalyst the enzymes regulate the speed and specificity of a reaction, but unlike the catalyst they are produced by living cells only. All components of cell including cell wall and cell membrane have enzymes. Every cell produces its own enzymes because they can not move from cell to cell due to having high molecular weight. Maximum enzymes (70%) in the cell are found in mitochondrion. The study of the composition and function of the enzyme is known as enzymology.

The term enzyme (meaning in yeast) was used by Willy Kuhne (1878) while working on fermentation. At that time living cells of yeast were thought to be essential for fermentation of sugar. Edward Buchner (1897), a German chemist proved that extract zymase, obtained from yeast cells, has the power of fermenting sugar (alcoholic fermentation). Zymase is complex of enzymes (Buchner isolated enzyme for the first time).

Later J.B. Sumner (1926) pre

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Chapter 24 Microbes in Human Welfare Microbiology

Chapter 24 Microbes in Human Welfare Microbiology

 

 

  Introduction.                                                                                                                                                       

Microbiology is the branch of science, which deals with the study of microorganism and their process is called as microbiology. Antony Von Leeuwenhoek is known as father of microbiology and father of modern microbiology is Robert Koch. Microbiology is the study of living organism of microscopic, which include bacteria, fungi, algae, protista, viruses, etc. It is concern with their forms, structure, reproduction, physiology, metabolism and classification. It includes the study of their distribution in nature and relationship to other living organism. Their effects on human beings and on other animals and plants. Their abilities to makes physical and chemical change in our environment.

 Bacteria.                                                                      &nbs

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Chapter 23 Strategies for Enhancement of Food Production Part 2

Chapter 23 Strategies for Enhancement of Food Production Part 2

 

 

 Sericulture.                                                                                                                                                             

Sericulture is the breeding and management of silk worms for the production of silk. It has been practiced in India since second era or century B.C. The silk which is produced by silk worm is of a valuable natural protein fibre. Silk worms are the larvae of silk moths. The rearing of silk worm for the production of silk is known as sericulture.

  1. History of silk : Historical account of use of silk and rearing of silk worm eggs, larvae and cocoons are available from china. It was Lotzu the empress kwang-Ti who for the first time discovered the silk thread and its source the silk worm cocoon. The technique of sericulture was kept as a secret by the chines people. In about 550

B.C. The sericulture technique was diffused to European countries. The available mythological literature deals with facts rearing the use of silk in ancient India. By about 1000 A.D. the sericulture was in practice in China, Europe and India, China was the leading country in this

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Chapter 22 Strategies for Enhancement of Food Production Part 1

Chapter 22 Strategies for Enhancement of Food Production Part 1

 

 

Introduction

The rearing of animals for specific purposes is called domestication, and such animals are called domestic animals. Domestication of animals started during the 'hunting and gathering phase' of human civilization. Man domesticates a variety of animals for food transport agricultural operation, wool, fur, study, research and pleasure. Cow buffaloes, goats, sheep and pigs for meat and honey bee for honey. Cattles, horses, mules, donkeys, camels, elephants and reindeer are used for transport. The domesticated animals play an important role in the economy of rural India. The first animals to be domesticated may have been the dog and goat. The various breeds of domestic animals we use today have evolved from wild ancestors through selective breeding. Pets, livestock, poultry, Fishery, Sericulture, apiculture and Lac culture are briefly discussed in this chapter. The branch of agriculture specializing in the breeding raising care and utilization of domestic animals is known as animal husbandry.

 Dogs and Cats.                                                                                                                                                     

Dogs a

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Chapter 21 Human Health and Diseases Part 2 smoking alcoholism drug addiction

Chapter 21 Human Health and Diseases  Part 2 smoking alcoholism drug addiction

 

 Smoking.                                                                                                                                                                  Smoking of tobacco dried and cured leaves of plant ‘Nicotiana tobacum’ and N. rustica in the form of cigars, cigarettes, bides etc. is very toxic to the body. Smoke of tobacco contains about 300 compounds. The main compounds are nicotine, CO, HCN, polycyclic aromatic hydrocarbons, certain other stimulating products etc.

Nicotine in the blood stimulates the nervous system, relax the muscles, release adrenalin hormone and increase the rate of heart beats. In pregnant ladies growth of fetus decreases and loss of weight may takes place.

  1. Tobacco : The tobacco was first smoked by Red Indians in America. It then spread to European countries in the early 1600’s, and today a large part of the world population smoke tobacco, while some others chew it.
  2. Effect of Nicotine : Smoking was reported to produce a feeling of tranquility (calmness) and in some ca

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Chapter 20 Human Health and Disease

Chapter 20 Human Health and Disease

 

 

“Disease” is a very wide term. Any change from the normal state that causes discomfort or disability or impairs the health may be called a disease. The oxford English Dictionary defines disease as “a condition of the body or some part or organ of the body in which its functions are disturbed or deranged”. A person free of disease is often said to be healthy. This is not fully true. The term “Health” has a very wide scope. The World Health Organization (WHO) gave the following definition of health in 1948 –

“Health” is a state of complete physical, mental and social well-being, and not merely an absence of disease or infirmity”. The WHO definition of health recognizes three dimensions of health : physical mental and social. The physical health can be determined by various tests, but it is difficult to assess the mental health and social well- being.

 Disease Agents.                                                                                                                                                    

The disease agent is a factor (substance or force) which causes a disease by its excess or deficiency or absence. These agents are of five main types :

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Chapter 19 Evolution

Chapter 19 Evolution

 

 

 

 Origin of Universe and Earth.                                                                                                                            

Philosophers and scientists have been busy to solve the riddle as to how the universe and our earth were formed and how and when 'life' originated on earth. The branch of life science for the study of 'Origin of life' and evolution of different forms of life on earth was called Bioevolution or Evolutionary Biology by Mayer, (1970).

The study of universe or cosmos is called Cosmology. Our earth belongs to the Solar system having nine stars called planets constantly rotating around a common Sun. On the basis of the order of the distance from the sun these planets include Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto while moon is a satellite of earth. The universe is made up of matter and energy and it was formed about 10 to 13 billion years ago as a red hot, dense, rotating gaseous cloud of cosmic dust called Ylem or primaeval matter. The Ylem consisted of particles of matter (like neutron, proton and electron) and antiparticles of antimatter. Scientists like Lemaitre (1931), Gamow (1948), Dicke (1964) etc. supported the Big-Bang Hypothesis which explains that collision between these particles and antiparticles caused a tremendous explosion to form atoms of hydrogen. Cosmic evolution began with the fusion of hydrogen atoms with progressively heavy atoms of different elements. Stellar systems and stars were formed by spreading of original gaseous cloud into the space and divided into smaller and larger masses

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Chapter 18 Reproductive Health

Chapter 18 Reproductive Health

 

 

 

 

 

 

 

 

  Introduction.                                                                                                                                                           

History of man is only about 50,000 years old. In the course of human history there have been three major explosions, each corresponding to a major changes in the environment. The first population explosion occurring about 20,000 years ago. It was brought about by the use of tools that allowed improvement in hunting and food gathering methods. The second revolution occurred about 6,000 years ago, and was brought by improvements in farming. The third revolution was brought about 300 years ago and was caused by improvement in food production, industry and medicine. If the present birth rate is maintained, it is stated that only one square feet of the earth surface will be available per one person within the next 700 years.

Definition : The term population refers to the total number of individuals of the same species occupying a particular geographic area at a given time. This definition of population was given by Clark in 1954.

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Chapter 17 Human Reproduction Part 2

Chapter 17 Human Reproduction Part 2

 

 

  Introduction.                                                                                                                                                           

All events which change a zygote or a blastos (a reproductive unit in asexual reproduction e.g., whole organism e.g. Amoeba, a bud e.g. Hydra, or a body fragment e.g. sea anemone) into a fully developed organism is called development. The entire process of development, which passes through embryo formation is called embryogenesis. Von Baer is commonly called “The father of modern embryology.”

 Embryonic development.                                                                                                         &nb

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Chapter 16 Human Reproduction Part 1

Chapter 16 Human Reproduction Part 1

 

 

 

 

 

 

 

 

 

   Reproduction and its type.                                                                                                                               

Reproduction : Reproduction is the ability of living organism to produce a new generation of living individuals similar to themselves.

Basic features of reproduction : All organisms reproduce. Modes of reproduction vary in different organisms. However, all modes have certain common basic features. These are

  1. Replication of DNA. This is the molecular basis of reproduction.
  2. Cell division, only mitotic, or both mitotic and meiotic. This is cytological basis of reproduction.
  3. Formation of reproductive bodies or units.
  4. Development of reproductive bodies into offspring.

Types of reproduction : These are of two main types

(i) Asexual (Non-gametic)                     (ii) Sexual (gametic)

(i) Asexual reprod

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Chapter 15 Chemical Coordination and Integration

Chapter 15 Chemical Coordination and Integration

 

 

Introduction : Endocrine system formed of all endocrine glands of body. Though different endocrine glands are different in embryonic origin and are isolated from one another but these interact with one another so collectively form an endocrine system. Endocrine system along with nervous system, controls and coordinates the body functions and maintains a homeostais. So both are collectively form neuro-endocrine system. The study of these two systems is called neuro-endocrinology.

The nervous system achieves functional co-ordination and integration for quick responses of body, like a high- speed service. Contrarily, the endocrine system achieves co-ordination and integration for slow responses of body, like a low speed service.

Glands of body : A cell, a tissue or an organ which secretes certain useful chemical compounds is called a gland. Animals have three types of glands.

  1. Exocrine gland (Gr., ex = out + krinein = to secrete) : These glands have ducts for discharging their secretions. Therefore, they called duct glands. ex – Liver, Sweat gland, Sebaceous gland, Gastric glands and some intestinal glands.
  2. Endocrine glands ( Gr., endo = within + krinein = to secrete) : These glands lack ducts and pass secretions into the surrounding blood directly. Therefore they called ductless glands. ex – Thyroid, parathyroid, adrenal, pituitary, pineal body and thymus.
  3. Heterocrine glands : These glands consist of both exocrine and endocrine tissue. The exocrine discharge its secretion by a duct and the endocrine tissue discharge its secretion i

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Chapter 14 Neural Control and Coordination

Chapter 14 Neural Control and Coordination

 

 

 

 

 

 

 

 

 

  Introduction                                                                                                                                                             In all the multicellular animals above the level of sponges, the system meant to perceive stimuli detected by the receptors, to transmit these to various body parts, and to effect responses through effectors, is called nervous

system. In vertebrates, it is highly specialized and plays at least three vital roles

  1. Response to stimuli : By responding to all sorts of stimuli, it acquaints the organism with them so that the organism may react and orient itself favourably in the surrounding environment.
  2. Coordination : Along with endocrine system, the nervous system also serves to coordinate and integrate the activities of various parts of the body so that they act harmoniously as a unit. This makes possible the integrated control of the internal body environment (homeostasis). However, the nervo

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Chapter 13 Locomotion and Movement

Chapter 13 Locomotion and  Movement

 

 

Introduction : That branch of science which deals with bones and cartilage is called Osteology. Bones are made up of a protein called ostein and cartilage are made of a protein called chondrin. Hence study of bones is called osteology and study of cartilage is called chondrology. Body of animals (vertebrates) is supported by skeleton.

 Skeleton                                                                                                                                                                  

The hardened tissues of the body together form the skeleton (sclero = hard). Organism will remain small and slow moving if there had been no skeleton for support and to serve as levers on which muscles can act. Skeleton of invertebrates is most often secreted on the surface, forming a lifeless or dead exoskeleton. Whereas skeleton of vertebrates develops most often underneath the surface forming a living or growing endoskeleton. Three types of skeletons develop in vertebrates :

  1. Epidermal horny exoskeleton : These include hard and horny of keratinized derivatives of epidermal layer of skin, such as claws, reptilian scales, bird fea

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Chapter 12 Excretory Products and their Elimination

Chapter 12 Excretory Products and their Elimination

 

 

 

Introduction : The component structural and functional units of the bodies of all organism are cells which have been looked as "miniature chemical factories" because of continuous metabolism taking place in these. It yields certain waste products which are, not only useless, but harmful to the cells and the body. Cells, therefore, throw out these wates, by diffusion, into their surrounding medium. Finally, these wastes are eliminated by the body into its external environment. This is, thus an important vital activity of all organism. It is called excretion.

Besides removing the metabolic wastes and impurities from the blood, the kidney also perform the important function of osmoregulation by regulating the amount of water in body fluids. The normally functioning kidneys produce a large volume of dilute urine when more water is taken, and a small volume of concentrated urine when water intake by the body is poor.

 Excretory organs of different organism.                                                                                                        

  1. Protozoans : In protozoans like Amoeba

 

and Paramecium carbon dioxide and ammonia are mostly excreted out by diffusion through general body surface. It is considered that the contractile vacuoles also play some role in the removal of excretory products.

  1. Sponges : In sponges, the nitrogenous metabolic

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  Text Box: Plant kingdom