INTRODUCTION TO BIOLOGY

A. Introduction

Biology (Gk: Bios = life, logos = knowledge)

Biology is the study of life and living beings.

Botany (Greek: Botane – herb or plant) deals with the study of plants and Zoology (Greek: Zoon – animal) deals with the study of animals.

The term Biology was coined by Lamarck and Treviranus in 1802 AD.

Aristotle is the father of Zoology/Biology/Science/Embryology.

Theophrastus is the father of Botany.

B. Branches of Biology

Branches Study of

Acarology: Ticks and mites
Actinobiology/Aerobiology: Flying organisms
Anatomy: Internal structure of plants and animals with naked eyes
Angiology: Blood vessels (Arteries and Veins)
Anthropology: Natural history of man
Aphidology: Aphids
Apiculture: Honey bees
Araneology: Spider
Arthrology: Joints
Autecology: Ecology of an individual species and its population
Auxanology: Mental status
Bacteriology: Bacteria
Batrecology: Frogs
Biochemistry: Chemistry of living organisms
Biometrics/Biostatistics: Application of statistics for analyzing biological problems
Biotechnology: Microbial application in industries
Bryology: Bryophytes
Carcinology: Crustaceans (Arthropods)
Oncology: Tumors and cancer-causing cells
Cardiology: Heart
Cetology: Whales
Chondrology: Cartilages
Cnidology : Coelentrates
Conchology: Shells of Mollusca
Craniology: Skull
Cryobiology: Life at low temperature
Cytology: Detailed structure of cell
Dactylography : Finger prints

Dendrochronology: Estimation of age of the trees counting annual rings
Dendrology: Shrubs and trees
Dermatology: Skin and skin-related diseases
Desmology: Ligaments
Ecology: Study of plants and animals in a reciprocal relationship with the environment
Emnology: Menstrual cycle
Entomology: Insects
Epidemiology: Occurrence and distribution of disease
Ethnology: Mankind (human races)
Ethology: Animal behaviour
Etiology; Cause of disease
Eugenics: Improvement of the human race through the laws of heredity or laws of genetics
Euphenics: Improvement of the human race by Genetic engineering (altering protein during protein synthesis)
Euthenics: Improvement of the human race through better nutrition and environment
Exobiology: Study of life in space
Fishery: Study of catching fish or other products of the sea, lakes or rivers
Floriculture: Study of flower producing plants
Food technology; Study of production and preservation of foods
Forensic: science Study of detection of crimes
Forestry: Study of developing, cultivating, and conserving forests
Genetics: Heredity and variation
Gerontology: Process of growing old
Gynaecology; Disease related to female genital tract
Haematology: Blood
Helminthology: Helminthes or parasitic worms
Herpetology: Reptiles
Histology: Tissue structure
Hypnology: Sleep
Ichnology: Fossils footprints
Ichthyology: Fishes
Immunology: Study of body defence and resistance to infections
Karyology: Study of the nucleus of a cell
Kinesiology: Movement of body muscles
Larynology : Study of larynx
Lepidopterology: Study of Butterflies
Limnology: Life in freshwater bodies
Mammology: Mammals
Mastology: Mammary glands (Breasts)
Microbiology: Microorganisms
Molecular Biology: Study of structure and activities of molecules in living beings
Morphogenesis: Embryology
Morphology: External form and structure of living organisms
Mycology: Fungi
Myology: Muscles
Myrmecology: Ants
Nematology: Nematodes
Nephrology: Kidney
Neurology: Nervous system
Ornithology: Nest of bird
Odontology: Teeth and gums
Oncology: Tumor or cancer
Ophiology: Snakes
Opthalmology: Eyes
Ornithology: Birds
Osteology: Bones
Otology: Study of ears
Palaeontology: Fossils
Palynology: Pollen grains
Parasitology: Parasites
Parazoology: Sponges
Pathology: Disease-causing organisms
Pharmacology: Drugs
Phenology: Migration of birds
Phrenology: Activities of brain and feelings of human
Phylogeny: Evolutionary history of animals
Physiology: Functioning of an organ
Physiotherapy: Study of treatment of diseases, bodily weaknesses, or defects by physical remedies or exercise
Physiotherapy: Treatment of disease by exercise
Pisciculture: Rearing of fishes in the pond
Pomology: Fruits
Proctology: Study of hindgut and rectum
Radiobiology: Effects of radiation on plants and animals
Radiology/Actionobiology: Study of the effect of radiation on living organisms
Rhinology: Study of nose
Saurology: Lizards
Sericulture: Rearing of silkworms and obtaining silk
Ophiology or Serpentology: Snakes
Serology: Study of seeds
Synecology: Species living together making a community
Taxonomy: Classification, arrangement, identification, and nomenclature
Tectology: Study of morphology and organization of the body
Teratology; Embryonic disease
Trichology: Hair
Trophology: Food and Nutrition
Urology: Study of urine and diseases
Veterinary Science: Study of domestic animals and their health
Virology: Study of viruses
Zoogeography: Distribution of animals on earth
Zootechology: Breeding and domestication of animals

Zymology : Fermentation

C. Fathers of Various Branches

Name	Father of
Hippocrates	Medicine
Hugo de Vries	Mutation
Leonardo da Vinci	Paleontology
Empedocles	Evolutionary ideas
Robert Koch	Bacteriology
K. Landsteiner	Blood group
Carolus Linnaeus	Taxonomy
G. J. Mendel	Genetics
Bateson	Modern genetics
Aristotle	Biology, Zoology and Embryology
Thomas Addison	Endocrinology
Edward Jenner	Immunology
Marcello Malpighi	Microscopic Anatomy
Louis Pasteur	Microbiology
G. Cuvier	Comparative Anatomy
Robert Hooke	Cytology
Swanson	Modern Cytology/Cell Biology
W. Harvey	Blood circulation
Arachibald Garrad	Human Genetics
T. H. Morgan	Experimental Genetics
Ernst Von Baer	Modern Embryology
Andreas Vesalius	Anatomy
Alexander Fleming	Antibiotics
Charaka	Ayurveda
Antony Van Leeuwenhoek	Bacteriology
Justus von Liebig	Biochemistry
Paul Ehrlich	Chemotherapy
Alec Jeffreys	DNA fingerprinting
Einthoven	ECG
Khorad Lorenz	Ethology
Paul Berg	Genetic Engineering
Harrison	Tissue Culture

D. Various Connecting Links

Organisms	Link Between
Virus	Between Living and Non-living
Euglena	Between Plants and Animals
Proterospongia	Between Protozoa and Sponge
Peripatus	Between Annelida and Arthropoda
Neopilina	Between Annelida and Mollusca
Balanoglossus	Between Chordata and Non-chordata
Protopterus or Lung Fish	Between Fish and Amphibia
Seymouria	Between Amphibia and Reptiles
Ornithorynchus	Between Reptiles and Mammals
Archaeopteryx lithographica	Between Reptiles and Birds

E. Books and Authors

Name of Books	Authors
Historia Animalia	Aristotle
Origin of Species by Natural Selection	Darwin
Systema Naturae & Species Plantarum	C. Linnaeus
Micrographia	Robert Hooke
Philosphie Zoologique	Lamarck
Historia Plantarum	Theophrastus
The Origin of Life	A.I. Oparin

F. Sea Creatures with their Genus and Phylum

Name of Animals	Genus	Phylum
Sea pen	Pennatula	Coelenterata
Sea fan	Gorgonia	Coelenterata
Sea pansy	Renilla	Coelenterata
Sea stick	Virgularia	Coelenterata
Sea mouse	Aphrodite	Annelida
Sea mice/mica	Chiton	Mollusca
Sea hare	Aplysia	Mollusca
Sea lemon	Ximenia	Mollusca
Sea squirt	Herdamania	Urochordata
Sea horse	Hippocampus	Pisces
Green Sea Turtle	Chelonia	Reptilia
Sea cow	Manatee	Mammalia
Sealion	Eumatoplas	Mammalia

G. False Fishes

Name of Animals	Phylum
Jelly fish (Aurelia)	Coelenterata
Cray fish (Lobster)	Arthropoda
Silver fish (Lepisma)	Arthropoda
Cuttle fish (Sepia)	Mollusca
Devil fish (Octopus)	Mollusca
Star fish (Asterias	Echinodermata
Hag fish (Myxine)	Cyclostomata (Chordata)
Whale fish	Mammalia

 

H. False Worms

Name of Animals	Phylum
Clam or Sand or Rag worm (Nereis)	Annelida
Paddle worm (Chaetopterus)	Annelida
Peacock worm (Sabella)	Annelida
Lung worm (Arenicola)	Annelida
Scale worm (Polynoe)	Annelida
Peanut worm (Sipunculus)	Annelida
Walking worm (Peripatus)	Arthropoda
Glowworm (Lampyris sp.)	Arthropoda
Silk worm (Bombyx)	Arthropoda
Ship worm (Teredo)	Hemichordata
Tongue or Acorn-worm (Balanoglossus)	Mollusca
Blind worm (Uraethyphlus)	Amphibia
Slow worm (Angus)	Reptilia

 

I. Diseases and Causative Organisms

i) BACTERIAL DISEASES

Diseases	Bacteria
Cholera	Vibrio cholera
Typhoid	Salmonella typhii
Tuberculosis	Mycobacterium tuberculosis
Leprosy	Mycobacterium leprae
Whooping cough	Bordetella pertussis
Tetanus	Clostridium tetani
Plague	Yersinia pestis
Gonorrhoea	Neisseria gonorrhoea
Diptheria	Corneybacterium diphtheria
Meningitis	Nesseria meningitidis
Syphilis	Treponema pallidum
Bacterial dysentery (Shigellosis)	Shigella sonnei

ii) PROTOZOAN DISEASES

Disease	Causative Protozoa
Giardiasis	Giardia lambia
Kala-azar	Leishmania donovani
Malaria	Plasmodium species
Sleeping sickness	Trypanosoma
Amoebic dysentery (Amoebiasis)	Entamoeba histolytica
Chagas disease	Trypanosoma

iii) HELMINTHIC DISEASES

Disease	Causative Agent
Ascariasis	Ascaris lumbricoides
Elephantiasis or Filariasis	Wuchereria bancrofti
Taeniasis of Cysticercosis	Taenia solium
Ancyclostomiasis	Ancyclostoma duodenale
Schistosomiasis	Schistosoma
Eye worm disease	Loa loa
Guinea worm disease	Dracunculus

iv) VIRAL DISEASES

Disease	Causative Agent
AIDS	HIV
Rabies	Rabies virus
Poliomyelitis	Poliovirus
Mumps	Paramyxo virus
Common cold	Rhinovirus

TERMINOLOGIES USED IN THE CHARACTERS AND CLASSIFICATION OF ORGANISMS

1. Cellularity:

· Cell is the structural and functional unit of life.
a. Unicellular or acellular: Body is made up of a single cell that performs all life activities. Structurally protozoans are unicellular as they have only one cell and functionally acellular as the body consists of a mass of protoplasm not divided into cells.
b. Multicellular: Body is made up of many cells. All others except protozoans. They are called metazoans.

2. Body Organization
a. Protoplasmic or molecular grade: All the life activities are confined within the boundaries of a single cell. It is the lowest level of organization and occurs in protozoans and other unicellular organisms.
b. Cellular grade: Cells perform all life activities. No coordination among cells, so no distinct tissues, 

E.g. Porifera
c. Tissue grade: Cells combine to form tissues for specific functions. In coelenterates, nerve cells form a network.
d. Organ-system grade: Cells organize into tissues, tissues into organs, organs into systems, 

E.g., Platyhelminthes- chordates

3. Body plan
a. Cellular form: Protozoa
b. Cell aggregate plan: A cluster of cells with the limited division of labour; 

E.g. sponges (Porifera).
c. Blind sac form: Having mouth but no anus. Ingestion and egestion through the same opening.

E.g. Coelenterates, Flatworms
d. Tube within a tube body plan
∙ Most complex body plan, tissue organization forms organ and organs form system.
∙ Has two openings (mouth and anus) and the digestive tube is in the form of the tube running through the centre of the body.

E.g. higher invertebrates (Annelida, Arthropoda, Mollusca and Echinodermata) and Mammals.

4. Germ layers
· Primary layers of cells differentiate in the animal embryos and give rise to all the tissues/organs of the fully formed individual
a. Diploblastic: Two germ layers- outer ectoderm and inner endoderm 

E.g. Sponges and coelenterates
b. Triploblastic: Three germ layers- outer ectoderm, middle mesoderm and inner endoderm, 

E.g. Flatworms to chordates

5. Body surfaces
· Bilaterally symmetrical animals show various body surfaces.
a. Anterior end: Towards the mouth
b. Posterior end: Towards the anus
c. Dorsal surface: Parts away from the ground in a natural position
d. Ventral surface: Parts towards the ground in a natural position
e. Lateral surface: Parts towards the sides of the body
f. Medial surface: Parts towards the central longitudinal axis of the body
g. Laterally compressed: Flattened laterally

6. Segmentation
· Type of body form having a linear sequence of units or segments possessing a similar or modified structure
a. Unsegmented: Body without segments, i.e. roundworms, molluscs, echinoderms
b. Metamerism or true segmentation: External segmentation corresponds to internal segmentation. It is found in annelids, arthropods and chordates
c. Pseudosegmented: False segments, i.e. Segmentation in tapeworm

7. Symmetry
c.It is the similarity of parts in different regions and directions of the body.
a. Asymmetrical: Body is not divisible into similar halves by any plane, i.e. Amoeba, some sponges and some molluscs.
b. Symmetrical: Body is divisible into similar halves through one or more planes
c. Spherical symmetry: Body can be divided into two halves by any plane passing through the centre of the body.

Example: Volvox.
d. Bilateral symmetry: It is the type of symmetry in which the body of an individual can be divided into two equal halves by a median longitudinal plane only. It is found in many invertebrates and all vertebrates.
e. Radial and biradial symmetry: Radial symmetry is the type of symmetry in which the body of an individual can be divided into two equal halves by any plane passing through the centre from top to bottom.

· It is found in some sponges (e.g., Sycon), coelenterates (e.g., Hydra, Jellyfish), and echinoderms (e.g., starfish).

· Body can be divided into two equal halves by one or two vertical planes only-biradial symmetry i.e. Sea anemones

8. Habitat:

· Place where an organism lives (Aquatic and terrestrial)
a. Aquatic: Live only in water
i. Freshwater: Live in rivers, lakes, ponds
ii. Marine: Live in seas or oceans
b. Terrestrial: Living on land e.g. lizards, man
i. Volant or Aerial or Flying: Fly on air e.g. winged insects, birds and bats
ii. Arboreal: Live on trees e.g. monkeys
iii. Scansorial: Climb walls, rocks etc, e.g. wall lizard, flying squirrel etc
iv. Cursorial: Fast runners e.g. Horses, Kangaroos, Dogs, Cheetah etc
v. Fossorial or Subterranean: Burrowing e.g. earthworm, snakes, rabbit etc
Other terms related to habitat
a. Solitary: Live alone e.g. man, cat, dog, grasshopper, tapeworm etc.
b. Colonial: Live together in a group with the division of labour e.g. bees, termites, wasps, ants etc.
c. Gregarious: Live together but no division of labour e.g. Locust
d. Sedentary: Fixed to some substratum e.g. Sycon, Obelia
e. Free swimming: Move freely in water e.g. tadpole of frog, Paramecium etc
f. Free-living: Lead an independent life e.g. horse, dog etc
g. Parasitic: Depend on others for food and protection e.g. tapeworm, Liver fluke, Ascaris etc.
h. Sessile or sedentary: Stalk absent. Example: Sycon
i. Stalked: Stalk present e.g. Vorticella
j. Pelagic: The animals occur on the surface water of the sea.
k. Benthic: Live on bottom of sea e.g. starfishes, sea cucumbers, sponges, corals etc.
l. Abyssal: The animals found in deep midwater of the sea where light penetration is low.
m. Littoral: Live in the intertidal zone of the sea coast.
n. Lentic: Live in standing water bodies like pools, ponds, lakes
o. Lotic: Running water bodies like rivers and streams

9. Body Temperature
a. Cold-blooded or ectothermic (poikilothermic): Those animals whose body temperature varies according to the temperature of the environment. For example, fishes, amphibians and reptiles.
b. Warm-blooded or endothermic (homeothermic): Those animals whose body temperature remains constant according to the temperature of the environment. Examples: birds and mammals.

10. Coelom:

· Cavity between the body wall and gut wall
a. Acoelomates: Animals without coelom- protozoans to flatworms
b. Pseudocoelomate: Animals with false coelom derived from blastocoel of embryo-roundworms.
c. Eucoelomates or Coelomates: Animals with true coelom (lined with mesoderm)-Annelids, echinoderms and chordates. It is of two types.
i. Schizocoel: Coelom formed by splitting of mesoderm- annelids, arthropods and molluscs
ii. Enterocoel: Coelom formed by linear series of archenteron- echinoderms and chordates
d. In haemo-coelomate, coelom contains blood- arthropods and molluscs
Sponges and coelenterates also bear cavities in their bodies called spongocoel and coelenteron respectively but these are not identical with coelom of higher animals.

11. Locomotory organs
· Pseudopodia (Amoeba), flagella (Euglena), cilia (Paramecium), setae (Earthworm), parapodia (Nereis), appendages (Arthropoda), muscular foot (Mollusca), tube feet (Echinodermata), fins (fishes), paddles, flippers, webbed feet, limbs (vertebrates)

12. Nutrition

· Process of taking food
a. Holozoic: The type of nutrition in which an animal takes food in solid form, ingestive
b. Holophytic: Plant-like nutrition or autotrophic nutrition
c. Saprozoic: Animals feeding on dead organic matter e.g. Earthworm
d. Saprophytic: Plants feeding on dead organic matter e.g. Fungi
e. Parasitic: Live on other organisms e.g. Liver fluke, tapeworm
f. Mixotrophic: Feed by more than one method e.g. Euglena feeds holophytically and saprozoically.
g. Herbivorous: Feed on plants e.g. deer, cattle etc.
h. Carnivorous: Feed on animal flesh e.g. tiger, lion etc.
i. Omnivorous: Feed on plants and animals both e.g. crow, man etc.
j. Filter-feeder: Feeding on smaller organism rejecting larger Example: Paramecium

13. Skeleton:

· Combination of bones.
a. Exoskeleton: Skeleton outside the body and is made up of non-living materials (chitinous cuticle- arthropods, shell- molluscs, feather, bird, hair and nail- mammals)
b. Endoskeleton: Cartilage and bone inside the body of vertebrates and in invertebrates such as sponges, it is made up of calcareous and siliceous spicules

14. Respiration
a. Protozoa, Porifera, Roundworm: No (through general body surface)
b. Coelenterata and Platyhelminthes: No respiratory and circulatory systems
c. Fish, tadpoles, some molluscs, some echinoderms: Gills
d. Arthropods: Trachea (Insects), book lungs (arachnids)
e. Frog, lizard, snake, bird, mammal: Lungs

15. Circulation
a. Open circulation: Blood flows in large open spaces. Blood vessels are absent- arthropods, molluscs
b. Closed circulation: Blood flows through the closed blood vessels-annelids and all vertebrates

16. A. Digestion
i. Intracellular: inside the cell, Protozoa to Coelenterata
ii. Extracellular: outside the cell- digestion in Hydra, earthworm and all the other animals with the alimentary canal

B. Alimentary canal
i. Incomplete alimentary canal: Absence of anus- Coelenterates and flatworms
ii. Complete alimentary canal: Both mouth and anus or cloacal aperture present, roundworms to mammals

17. Excretion

· Removal of metabolic wastes from the body.

· The excretory organs found in different groups of animals are:
a. Protozoans: contractile vacuoles
b. Sponges, coelenterates and echinoderms: through the general body surface
c. Flatworms: flame cells or protonephridia or solenocytes
d. Roundworms: a modified system of cells with internal canals that fuse to form a single tube. It opens to the exterior through the excretory pore.
e. Annelida: nephridia
f. Arthropoda: malpighian tubules, coxal glands or antennary (green) glands in crustaceans
g. Mollusca and vertebrates: kidneys

Types of animals on the basis of removal of nitrogenous wastes:
a. Ammonotelic animals:

· They excrete ammonia. Examples: Protozoans (e.g. Amoeba, Paramecium), Sponges (e.g. Sycon), Cnidarians or Coelenterates (e.g. Hydra), Liver fluke, Tapeworm, Ascaris, Nereis, Earthworm, Leech, Prawn, Pila, Bony fish (e.g. Labeo), Amphibian tadpoles, tailed amphibians (e.g. Salamanders), Crocodiles.

b. Ureotelic animals: They excrete urea. Examples, Ascaris and Earthworm are both ammonotelic and ureotelic, Cartilaginous fishes (e.g. Sharks and Rays), semi-aquatic amphibians (e.g. Frogs and Toads), Turtles, Alligators, mammals including man.

c. Uricotelic animals: They excrete uric acid. Examples: Most insects, some land crustaceans (e.g. Oniscus-commonly known as woodlouse), Land snails (e.g. Helix- commonly called “Sand snail”), land reptiles (lizards and snakes), birds

d. Aminotelic animals: They excrete excess amino acids. Examples: Some molluscs (e.g. Limnea, Plaudina, Unio), some echinoderms (e.g. Asterias-Star fish)

18. Reproduction
1. Asexual reproduction: Takes place by only one parent
a. Binary fission: Longitudinal or transverse- production of two daughter individuals- Paramecium (transverse), Euglena (longitudinal)
b. Multiple fission: Production of many daughter individuals- Plasmodium
c. Regeneration: Ability to develop lost parts- coelenterates, flatworms, echinoderms

2. Sexual reproduction: Male and females are involved. Male and female gametes are fused to form a zygote.
Other terms related to reproduction
a. Oviparous: Development of the embryo outside the body, inside the egg- arthropods, fishes, amphibians, reptiles, birds, egg-laying mammals

b. Ovo-viviparous: Development of the embryo inside the body but not providing extra nourishment as the placenta is absent. Individuals give birth to very immature young ones- sharks, some snakes (Viper), marsupials

c. Viviparous: Fertilization and development of the embryo inside the body of the female, embryo obtains nourishment from the mother through the placenta, give direct birth to young ones- most mammals

d. Monoecious or bisexual or hermaphrodite: Male and female sex organs are found in one individual- flatworms and annelids, e.g. Liver fluke, earthworm, leech, tapeworm etc.

e. Dioecious or unisexual: Separate male and female sex organs/ male and female sex organs are found in each individual- roundworms, arthropods and vertebrates (man, cockroach, frog)

f. Sexual dimorphism: Morphologically different male and female, Peacock, Peahen, lion, lioness, Ascaris, Man

g. Protoandry: Testes mature earlier than the ovaries- Earthworm

h. Protogyny: Ovaries mature earlier than the testes- Man, Herdmania

19. Fertilization
a. External: Outside the body of a female e.g. frog, fish, starfish
b. Internal: Inside the body of females e.g. reptiles, birds, mammals
c. Self-fertilization: Fusion of male and female gametes of the same parent takes place. E.g. tapeworm
d. Cross-fertilization: Fusion of male and female gametes of the different parents takes place. E.g. all fishes, amphibians, reptiles, birds and mammals

20. Development
a. Direct development: Newly borne young resembles with the adult, no larval stage. E.g. Silverfish
b. Indirect development: Metamorphosis of larvae to become an adult, the larval stage is present. E.g. Silkmoth

21. Fate of Blastopore
a. Protostomia (first mouth): The mouth forms the first opening of the embryo namely Blastopore. E.g. Annelida, Mollusca and Arthropoda
b. Deuterostomia (second mouth): Anus develops from the Blastopore i.e. first opening of the embryo. E.g. Echinodermata to Chordates

Relation of Biology with other Sciences

● Biology or life sciences can’t be studied without the knowledge of physical sciences (Physics, chemistry, geography, climatology, mathematics etc.).
● Some new hybrid sciences have been developed due to the close relation of biology with other sciences like biophysics, biochemistry, astrobiology, biomathematics, biostatistics, sociobiology, bioengineering, bio chromatography, biogenetics, biotechnology, biomedical engineering, biogeography etc.
● Our present knowledge in the field of biology has been achieved with the assistance of physical sciences i.e. physics and chemistry.

1. Relation of biological science with physics (Biophysics)
● Biophysics provides various tools, methods, techniques and principles of physics for the study of biological problems.
● Biology is related to physics in the following ways.
(i) A number of instruments being used by biologists have been provided by physics. Examples: spectrophotometer (an instrument for measuring the intensity of various parts of light), stethoscope (action of heart, lung etc.), ECG, X-Ray, MRI (Magnetic resonance imaging), Incubator, Microscope, Telescope, Light pipe, Spectacles etc. These instruments help to study minute details of cellular and sub-cellular components.
(ii) Some physiological processes like evaporation, transpiration, conduction of water and minerals occur according to the physical laws.
(iii) Photosynthesis is concerned with light. Light also induces definite patterns of responses in plants and animals.
(iv) The physical phenomena like force, energy, work, power, pressure, surface tension, cohesion have biological applications.
(v) The study on structure and functioning of the human eye requires knowledge from optics (the lenses and images).
(vi) Several camera trappings are used for the study of rare wild animals like snow leopard, tiger, rhino etc.
(vii) Many instruments like rain gauze, hygrometer, anemometer, thermometer etc. are used to study the humidity, precipitation, erosion, weather respectively are used to know about their effects on ecology.
(viii) Trekking devices like GPS sensors, fathometers, amplifiers, infra-red detectors, heat sensors are used to locate the position of locomotors and devices.
(ix) We are able to know the various movements of our body via. the use of physical instruments.
(x) Various diseases like kidney stones can easily be treated without any surgery i.e. by using laser technology.
Relation of biological science with Chemistry (Biochemistry)
● Biochemistry heavily depends upon the knowledge and techniques provided by chemistry to study biological processes.
● Biology is related to chemistry in the following ways.
(i) Metabolism (respiration, photosynthesis, digestion, nutrition, excretion) involves anabolism and catabolism which are purely chemical changes. Or All metabolic pathways involve chemical changes.
(ii) The genetic materials like DNA and RNA are formed by chemical compounds.
(iii) Living organisms are formed of organic and inorganic chemicals.
(iv) The enzymes, hormones and other chemicals formed within the plants and animals are exclusively chemical substances.
(v) The acid-base equilibrium maintains the proper pH in the protoplasm.
(vi) Mutation and genetic recombination that bring about variation have a chemical basis.
(vii) Movement of molecules in and out of the cells occurs by osmosis and diffusion.
(viii) Preservation of animals is done in formalin and Glycerine and Safranine are used in the lab for staining.
(ix) Decomposers convert complex organic compounds into simple inorganic compounds through the chemical process.
(x) Investigation on criminals and terrorists requires the study of the human nervous system and the study of glands, hormones etc. it also requires the knowledge of principles of inheritance and pedigree analysis etc.
(xi) Medicines, cleaning chemicals (hand wash, soaps and detergents) and cosmetic products which are essential for the biological purpose all are chemical compounds.

2. Relation of biological science with sociology
● Biology is related to sociology in the following ways.
● Sociology deals with society, social institutions and social relationships.
(i) Anthropology deals with the study of human beings in relation to distribution, origin, classification, relationship of races, environmental and social relations, culture etc. Actually, anthropology is the science of man and mankind
(ii) Biotechnology, bio-engineering and bio-medical engineering are closely interrelated with human beings.
(iii) Eugenics, euphenics and euthenics help in the development of the human race by means of genetics, drug treatment and better nutrition respectively. They all have sociological applications.
(iv) Animal behaviour and social relationships are dependent upon sociology.
(v) Due to social nature, many animals follow the pattern of social customs.
(vi) Study of human behaviour, social relationships and antisocial relationships needs an idea of biological science. Example: Investigation on criminals and terrorists requires the study of the human nervous system and study of glands, hormones etc. it also requires the knowledge of principles of inheritance and pedigree analysis etc.
● Similarly, the knowledge of geography is required for studying the distribution of organisms over the earth. Climatology is required to study the adaptation of organisms with the climate of the area, geology for the study of fossils, mathematics in data compilations and calculations.

3. The Science of exceptions- Biology
● We are unique, we are different just as every species is unique and different from every other; biology is a science of exceptions, not rules; of diversity, not grand unified theories. - Matt Ridley
● Physical sciences follow a specific set of rules and regulations. They are governed by a set of laws such as the law of gravity, the laws of thermodynamics, the law of conservation of mass and so on. They have very rare exceptions i.e. the principles in physical science are universal. But life sciences have very few universally applicable principles i.e. there are so many exceptions.

● So, biology is called the science of exceptions. The reasons for these exceptions are that living beings possess variations, have adapted themselves to different environments, modes of living and feeding. They show various degrees and directions of evolution in their different parts.

● Some exceptions are given below:
(i) Mature RBCs' of all mammals lack a nucleus except in Camel and Llama.
(ii) The heart of reptiles is three-chambered but in crocodiles, it is four-chambered.
(iii) Fishes are gill breathers but Protopterus (lungfish) have lungs and gills.
(iv) American salamander's larva gives birth to larva. [Axolotl is the aquatic larva of American Salamander that develops gonads and reproduces in spite of retaining its larval characters.]. The phenomenon is called paedogenesis (Gr. Pais- child, genesis- reproduction) or reproduction by the young larval stage. It is also called Neoteny.
(v) All mammals give birth to young ones (viviparous) but Duck-billed Platypus and Spiny anteaters (Echidna) are oviparous.
(vi) Usually birds fly but Ostrich, Kiwi cannot fly.
(vii) All land inhabiting animals drink water but kangaroo and desert rats never drink water.
(viii) DNA is a hereditary material in all living organisms except in some viruses. Example: in Tobacco Mosaic Virus (TMV), RNA functions as hereditary material.
(ix) The DNA is normally double-stranded but in some viruses like bacteriophages, it is single-stranded. RNA is double-stranded in Rheovirus.
(x) Monocot leaves have parallel venation and dicot leaves have reticulate venation. A monocot, Smilax has reticulate venation and a dicot, Calophyllum has parallel venation
(xi) Roots are positively geotropic but in mangrove plants like Sonneratia, the roots are negatively geotropic. They are called pneumatophores.
Roots are non-green and non-photosynthetic but are green and photosynthetic in Tinospora (Gilo).
(xii) A parasitic plant Cuscuta is grouped under dicot but lacks cotyledons.
(xiii) Young ones are produced by fertilization of eggs by sperm. However, the drones of honey bees develop from unfertilized eggs.
(xiv) Blood of all vertebrates is red due to the presence of haemoglobin but a shark Carcharhinus has colourless blood.
(xv) Usually animals are heterotrophic in nature but Euglena, a microscopic animal, is mixotrophic in nature and can prepare its own food in the presence of sunlight due to the presence of chlorophyll.
(xvi) Mushrooms are plants devoid of chlorophyll.
(xvii) Animals like dolphins and whales are mammals but resemble Pisces morphologically and are marine in nature.
(xviii) Plants like potato, corm and ginger have stems that show positive geotropism.
(xix) Mitochondria are the respiratory organelles of most of the organisms, but in prokaryotes, mesosome performs like mitochondria. (or performs the function of mitochondria).
(xx) Lichen is composed of both algae and fungi as an individual organism.
(xxi) Fern plants reproduce both asexually as well as sexually in two parts of life with alternation of generation.
(xxii Sponges are animals that never move from one place to another.
(xxiii) In birds, the urinary bladder is absent but present in Ostrich (Rhea americana).
(xxiv) Prokaryotes such as bacteria and blue-green algae have no organized nucleus.
(xxv) Difference in the genetic code in various types of organisms
(xxvi) Jellyfish with complex eyes and no apparent brain to send light signals to
(xxvii) Poisonous birds, heat-producing plants, venomous mammals
(xxviii) Adventitious roots are commonly developed from the nodes but in Ivy, they grow from internodes as well.
(xxix) Mammals have seven cervical vertebrae but cervical vertebrae are 6 in sea cow, 8 in ant bear and 9 in three-toad sloth.

SOME NOTABLE POINTS

∙ Protoplasm is the physical basis of life.
∙ Amoeba moves by pseudopodium and Paramecium by cilia.
∙ All living organisms (plants and animals) perform respiration.
∙ Metabolism is the various physiological activities going inside the body of a living organism.
∙ Metabolism = Catabolism (destructive change e.g. respiration) + Anabolism (constructive process e.g. photosynthesis)
∙ Irritability is the ability of the living organism to respond to stimuli.
∙ Euglena shows both plant and animal characters. It lacks a cell wall but bears chloroplast.
∙ Mature red blood cells of mammals lack a nucleus, while they are present in Camel.
∙ Animals must become adults to reproduce but the larval stage of salamander can reproduce.
∙ Birds can fly but ostrich and kiwi do not do so.
∙ The immediate source of energy in a cell is ATP. So, it is considered the energy currency of a cell.
∙ The development of egg from the unfertilized egg is Parthenogenesis.
∙ The central dogma of molecular biology is DNA → RNA → Protein.

CLASSIFICATION OF ORGANISMS

∙ Two Kingdom system of classification was given by Carolus Linnaeus.
∙ Carolus Linnaeus proposed the "Binomial System of Nomenclature".
∙ Linnaeus classification was primarily based on morphological similarities, so it is called the Artificial System of Classification.
∙ Natural system of classification was given by Benthem and Hooker.
∙ Five kingdom system of classification was given by American Taxonomist R.H. Whittaker.
∙ Hierarchic system of classification:
@ K P D C O F G S
1. Kingdom

2. Phylum (Animal) or Division (Plants)
3. Class

4. Order

5. Family
6. Genus

7. Species
∙ Term species was introduced by John Ray.
∙ Similar species can interbreed themselves. Hybrid and steriles are not species.

Also, Read our Other Related Notes for Entrance Exams:

• ANIMAL BEHAVIOUR: TAXIS, MIGRATION, DOMINANCE & LEADERSHIP
• ANIMAL ADAPTATION