The Introduction To Life Science

Science:
 Science is derived from Latin word “Scientia” meaning
knowledge.
 Study of world around us.
 Study of nature.
 Study of facts.
 Knowledge based upon experiments and observations.
 Theoretical knowledge
 Organized knowledge
 Eg. Chemical energy can be converted to electrical energy.
Technology:
 Practical science.
 Science in daily use.
 Mechanical science.
 Knowledge used in appliances and machines.
 Eg. Batteries, dry cell, generators, motors etc.
Branches of Science:
There are five branches of science.
1- Biology or Life Science.
2- Chemistry or Chemical Science.
3- Physics or Natural Science.
4- Astronomy
5- Geology

Biology:
Origin:
Derived from two Greek words.
 Bios means life .
Logos means study, thought, reasoning, discourse
So study of life is called biology.
Life: A set of characteristics which differentiate b/w living and non
living things.
 Every thing which exhibit the life is living.
2nd Definition
So study of living things is called biology.
Living Things: All those things which has the following characteristics
are called living.
1. Growth and Development:
 Increase in size and number of cells is called growth.
 Human body is composed of 100 trillion cells i.e., 1 ×10^14 cell
out of which 25 trillion are red blood cells.
 Cells ranged in size from 5 to 50 micrometer in diameter.
 Increase in complexity of organisms is called development.
 All the cells of the body aggregate with one another to give
specialized structures and specific functions forming tissues,
organs, organ systems and organisms.
2. Reproduction:
 To produce offspring.
 Actually to replace ones self.
 Some organisms reproduce asexually.
 While others reproduce sexually.
 Methods of reproduction are binary fission, budding,
regeneration, etc.
3. Sensitivity and response:
 Every organism sense stimulus.
  Stimulus is any change in external or internal
environment.
 Body reaction to any stimulus is called response.
 Responses may be physical or chemical.
 Such as sudden removal of hand when touching hot
object.
 Any hormone released to respond to a certain change.
 Such as ADH( Anti diuretic harmone) released to control
fluid and electrolyte balance of blood via kidneys.
4. Movement:
 Motion of body parts or whole body is called movement.
 Motion of whole body is called locomotion.
 Movements are of many types.
 Autonomic and paratonic movements etc.
5. Homeostasis:
 From two words
 Homois means same or standing or steady
 Stasis means state or conditions
 So, maintenance of constant internal environment is
called homeostasis.
 Homeostasis is maintained by mostly three processes.
 (a) Thermoregulation
 (b) Osmoregulation
 (c) Excretion
Internal Environment:
 The word malaue interior for internal environment was
used by Claude Bernard in the nineteenth century.
 Living organisms are composed of two types of fluid.
 1- Intracellular Fluid: The fluid inside the cells.
 2- Extracellular Fluid: The fluid outside the cells or the fluid
in which the cells bathe.
  The extracellular fluid is also called internal environment.
 An adult human body of 70 Kg has 60% body fluids equal
to 42 litres.
 The intracellular fluid is 40% i.e., 28 litres.
 The extracellular fluid is 20% i.e., 14 litres.
 The Extracellular Fluid consist of
 (a) The Plasma:- The fluid in the blood equal to 3 litres.
 (b) Interstitial Fluid:- The fluid in between the cells equal
to 11 litres.
 (c) Transcellular Fluid:- The fluid across the cells.
 i.e., cerebrospinal Fluid, peritoneal fluid, synovial fluid,
pericardial fluid and fluid in between the parietal and
visceral pleura of lungs etc.
6- Regulation:
 Every organism need regulatory mechanisms to maintain
homeostasis.
 In unicellular organisms the regulation is brought about
by different organelles and components of cell.
 Such as contractile vacoule brings excretions.
 Food vacoule brings digestion.
 Mitochondria produce energy.
 In multicellular organisms these functions are brought
about by different systems.
 Such as digestive system, respiratory system, excretory
system, nervous system, circulatory system etc.
7- Metabolism:
 All the chemical reactions.
 Two types
 1- Catabolic reactions= Reactions in which complex
molecules are broken down into smaller ones.
 2- Anabolic reactions=Reactions in which smaller
molecules combine together to form complex ones.
  All the catabolic reactions are exothermic.
 All the anabolic reactions are endothermic.
Exothermic Reactions:
The reactions in which the energy is released.
Endothermic Reactions:
The reactions in the energy is absorbed.
3rd Definition
Study of living and non living things.

Living Things Non Living Things

Atomic and cellular. Atomic but non cellular.

Eg. Amoeba, human etc Eg. Rocks, sand, stones etc
Acellular=not complete cell They are not acellular.
Eg virus and prions
Complete genetic material. No genes

Reproduce youngones No reproductions

Carry metabolism No metabolism

Specialized regulatory No regulation

mechanism
Maintain homeostasis No homeostasis

Sense external and internal No stimulation

stimuli
May be simple or complex No growth and development
Posses locomotion and No movement
movement

4Th Definition
The study of ecosystem.
Ecosystem is composed of biotic factors and affects of abiotic factors.
 All the living things of an ecosystem are known as biotic.
 All non living components of ecosystem are abiotic.
Abiotic factors are
 Atmosphere and wind
 Light
 Fire
 Inorganic nutrients
 Temperature
 Soil
 Water
 Gravity
 Topography
Biotic factors are
 Producers
 Consumers
 Decomposers

Branches of Biology:
There are three main branches of biology.
1- Zoology: Zoon means zoo
Study of animals
2- Botany: Botane means pasture
 Study of plants
3- Microbiology: Micro means small( the organisms which
can’t be seen with naked eyes)
Study of microscopic organisms
Sub Branches of Biology:
1- Morphology: Study of form and structure.
2- External Morphology: Study of external structure
3- Anatomy: Study of dissected parts or internal structure. It is also
called internal morphology.
4- Cytology: Kytos means cell
Study of structure and functions of cell and its organelles.
Organelle: means small organs.
The structural and functional unit of cell.
Cell: The structural and functional unit of life having capability
of carrying all life activities.
Cell consist of organelle and non organelle components.
Organelles are
 Nucleus
 Mitochondria
 Golgi Apparatus
 Endoplasmic reticulum
 Centrosome and centrioles (MTOC=microtubules
organizing centers)
 Plastids
 Vacoule
 Peroxisome
 Lysosome
 Ribosomes
 Dictyosome( golgi body in plants)
Other Substances are
 Cytoplasm
  Nucleoplasm
 Cytoskeleton
 Cell membrane
 Cell wall
5- Histology: Histos means tissue
The microscopic study of tissues and their functions .
Tissue
Group of cells performing similar functions
Or cell and interstitial fluid is called tissue.
Eg. Nerve tissue, muscle tissue, xylem tissue, phlegm tissue.
Tissues in Animals
There are four types of tissues in animals.
1- Epithelial Tissue:
 Glandular Epithelium= secretions
 Covering Epithelium=covers body surface and lines
the internal surface of organs.
2- Nervous Tissue ( Neurons and Neuroglia)
3- Muscle Tissue( Skeletal, smooth, and cardiac Muscle)
4- Connective Tissue( Embryonic, Proper, and Specialized
Connective Tissue)
Tissues in Plants
There are two types of tissues in plants.
1- Simple Tissues
 Meristematic Tissues
(i) Apical Meristem
(ii) Intercalary Meristem
(iii) Lateral Meristem
 Permanent Tissues
(i) Epidermal Tissues
 (ii) Ground Tissues
 Parenchymatous Tissues
 Sclerenchymatous Tissues
 Collenchymatous Tissues
2- Compound Tissues
(i) Xylem Tissues
(ii) Phloem Tissues
6. Physiology:
Study of functions of different organs.
7. Pathology:
Study of abnormal functions or diseases.
Disease: Abnormal homeostasis
8. Molecular Biology:
Study of organism or cell at molecular level.
Eg. Proteins, carbohydrates, lipids etc.
9. Ecology:
Study of relationship between organism and their environment.
10. Palaeontology:
Study of fossils.
11. Palaeobotany:
Study of Plant fossils.
12. Palaeozoolgy:
Study of Animal fossils.
13. Socio biology:
Study of social behaviour of organisms.
14. Human Biology:
Study of human beings.
15. Limnology:
Study of organisms in fresh water. Such ponds lakes streams
etc.
16. Marine Biology:
Study of organisms in marine water such as seas, oceans etc.
17. Genetics:
Study of Gene’s and inheritance.
18. Immunology:
Study of immune system.
19. Pharmacology:
Study of drugs and its effects.
20. Posolgy:
Study of drug dosage.
21. Gerantology:
Study of aging.
22. Ontogeny:
Study of complete developmental history of an organism.
23. Teratology:
Study of abnormal development such as polydactyl, acromegaly,
microcephaly etc.
24. Virology:
Study of viruses.
25. Bacteriology:
Study of bacteria.
26. Mycology:
Study of fungi.
27. Phycology:
Study of algae.
28. Ichthyology:
Study of fish.
29. Embryology:
Study of embryo.
Male × Female
Male gametes × Female gametes
(Sperm) (Ova or egg)
Zygote ( 1 week)embryo(2nd week to 8th
week)foetus( till birth)neonates( new born)infant( 2
 years)kid( 5years) child(12
years)young(18years)adult(18+years).

30. Demography:
Study of population.
31. Parasitology: Study of parasites
32. Biochemistry: Chemical compound and chemical processes
taking place in living organisms.
33. Biotechnology: Techniques to use organisms for benefit of
human beings.
34. Entomolgy: Study of insects.
35. Herpetology: Study of reptiles.
36. Synecology: Study of community
37. Autecology: Study of attributions of population.
38. Taxonomy: Tasso means arrange or classify
Nomos means laws of naming
Study of
 Identification
 Classification
 And naming of organisms
 Hierarchy(levels) of classification
Classification:
Arrangement of organisms into groups and sub groups
on the basis of similarities.
Taxon:
A rank or level of classification.
Levels of classification are
Ascending order= Specie, genus, family, order, class, phylum,
kingdom, Domain.
Descending Order= Domain, Kingdom, Phylum, Class, Order, Family,
Genus, Specie.
Taxon is inversely proportional to similarity
The higher the taxon, the lower the similarity
The lower the taxon, the more is similarity.
Domain:
 The highest taxonomic rank
 The least similarity
 Proposed by Carl Woese in 1990.
 Three Domains.
1. Eukarya= All eukaryotic organisms. Eg Plants,
animals, fungi, and protists
2. Eubacteria or bacteria= True bacteria eg
bacteria and cyanobacteria.
3. Archaea= Ancient, oldest bacteria, lives in
extreme conditions. Eg halophiles,
thermophiles, acidophilus, methanogens etc.
Specie:
 Smallest rank
 Highest similarity
 Group of same type of individuals which can breed.
 Fertile offspring in natural conditions
 Same no. of chromosomes.
 Similarities
1. Structural
2. Functional
3. Developmental
Exceptions
Male(62) × Female(64)  Mule( infertile)
 Donkey Horse

Female × Male  Hinny(infertile)

Donkey Horse

Male(38) × Female(38) Tiglions(fertile)

Tiger Lion

Female × Male Ligers(infertile)

Tigers Lions
Some Animals classification
Ranks Humans Cat,lion,tiger Frog
Domain Eukarya Eukarya Eukarya
Kingdom Animalia Animali Animalia
Phylum Chordata Chordata Chordata
Class Mammalia Mammalia Mammalia
Order Primates Carnivora Anura
Family Homonidae Felidae Rana
Genus Homo Felis Rana
Specie Sapiens Domestica(cat) Tigrina
Leo(lion)
Tigris(tiger)

Plant classification.
Some names in plants will end as
Phylum phyta
Class eae or ae
Order ales
Family aceae
Classification of Rice
Domain Eukarya
Kingdom Plantae
Phylum Treacheophyta
Class Angiospermae
Order Poales
FamilyPoaceae
Genus Oryza
Specie Sativa.
Naming of Organisms
 Carolus Linnaeus in 1753 proposed
 Binomial(Two Names) Nomenclature( Law of giving name)
 First Name Genus
 Second name Specie
 The 1st letter of genus should be capital.
 The remaining letters should be small.
 Letters will be written in Italics or underlined.
 The two names should be Latin
 1st name is noun
 2nd name is adjective

Levels of Organization.
 Hierarchy(levels) of Life
 Evolution
 Interactions
  Pattern of living
 No. of individuals
 Development from simplest to complex.
 Three levels
1. Biological Level
2. Cellular Level
3. Social Level
Biological Level of Organization:
 Composition of organism
 Interactions of cells
Matter:
 Anything which has mass and volume
 Mass and occupy space
 Everything is matter.
 Biotic and abiotic factors
 Matter is made of atoms
Atoms:
 The smallest particle of an element
 All properties of that element
 Can’t be divided by physical method
 Can or can not exist independantly
 Made of subatomic particles
 Nucleons( proton and neutron in nuclues)
 Electrons in shells
 They form elements
Elements:
 A pure sample of substance.
 Having uniform physical properties
 Total elements 118
 Natural Elements92
 Artificial Elements26
 Bio-elements:
 The elements found in living organisms.
 25 in number.
 Most commonly found are 16.
Major Bio-elements:
 Elements found in more than 1% protoplasm
 Make 99% of body mass.
Eg
Oxygen65%
Carbon18%
Hydrogen10%
Nitrogen3%
Calcium2%
Phosphorous1%
Minor Bio-elements:
 The elements found in less than 1% of protoplasm.
Eg
Potassium0.35%
Sulphur0.25%
Chlorine0.15%
Sodium0.15%
Magnesium0.05%
Trace Bio-elements:
Those which are found less than 0.01% of the protoplasm.
Eg.
Iron, Manganese, Zinc, Copper, Iodine.
Bio-Molecules:
 The molecules found in living organisms
 Two types
 1- Macromolecules
 Molecular weight>10000
 No. Of atoms >1000
 Eg. Haemoglobin, Starch, Glycogen etc.
 2- Micromolecules
 Molecular weight<10000
 No. Of atoms<1000
 Eg. Amino acids, Sugars, phospholipids etc.
 Micromolecules polymerize to form Macromolecules.
 Macromolecules polymerize to form Organelles.
1- Organelle Level:
 Small organs
 Membrane bound
 Single or Double membrane
 Structural and functional unit of cell.
 Ribosome is only organelle having no membrane
Organelles with double membrane
 Nucleus
 Mitochondria
 Endoplasmic Reticulum
 Golgi Body
 Centrosome and Centrioles
 Plastids
Organelles with single membrane
 Vacuole
 Lysosomes
 Peroxisomes
 Glyoxisome
2- Cell Level:
 The structural and functional unit of life.
 Organelles confined by a membrane.
 Two types
Prokaryotic Cell Eukaryotic Cell
Pro= before, Eu= true,
Karyon=Nucleus Karyon= Nucleus
No prominent Prominent nucleus
nucleus and nuclear with nuclear
membrane. membrane.
No membrane bound All membranous and
organelles such as non membranous
mitochondria etc. organelles are found.
Divide by binary Divide by mitosis and
fission, no mitosis meiosis
Have cell wall made Have cell wall made
of murein or of chitin of cellulose.
peptidoglycan.
Cellulose is absent Cellulose is present.
Contain free Contain both free
ribosomes only and attached
ribosomes
Ribosomes are 70S Ribosomes are 80S
Hereditary material Hereditary material
is DNA , having no is DNA, having
protein covering. protein covering
Number of Chromosomes are
chromosomes is one more than one
Mesosome is present Mesosome is absent
Mitochondrial Mitochondria along
enzymes are present with enzymes is
near cell membrane. present.
Chlorophyll pigments Chlorophyll pigments
are present in are present in
mesosome or chloroplast.
dispersed in
cytoplasm.
Contain circular DNA Contain linear DNA
present in irregularly present in the
shaped region called nucleus.
 Nucleoid or Nucleoid
Body
Flagella if present Flagella if present
lack 9+2 have 9+2
arrangement of arrangement of
microtubules. Consist proteins.
of single strand and
protein flagellin.
Eg. Bacteria, Eg. Plants, animals,
cyanobacteria etc fungi, protists etc.
3- Tissue Level:
 Group of cells performing similar function.
 Include intercellular substance.
 Particular function.
Eg
(i) Nerve Tissue:carry messages.
(ii) Muscle Tissue: help in movement
Etc.
4- Organ Level:
 Group of different tissues performing one major
function.
Or
 Structure composed of several tissues forming a
functional unit.
 Perform specialized functions.
Eg. Stmoach, Lungs, Heart, Brain, Skin etc.
 Skin is the largest organ of human body.
Organs of plants are
Roots, stems, leaves etc.
5- Organ System:
 Group of organs working together
 Perform specific function
  Most organs don’t function independently
 Such as digestive system ( liver, pancrease,
gallbladder bladder, stomach, intestines, esophagus
etc.)
 Some organs may be a part of two or more systems
 Such as pancrease as a part of digestive and
endocrine system.
6- Individual Level Or Organism:
 Different systems working together make up an
individual or organism.
 Composed of many cells.
 All systems work in coordination brought about by
Nervous and Endocrine system
 Work and interact with environment as a whole.
 Such as Rose, Mustard, Cow, Man etc.
Cellular Level Of Organization:
 All organisms are made up of cells.
 On basis of nucleus, there are two types
 1- Prokaryotes 2- Eukaryotes
 Cellular organization is of two types.
1- Unicellular Organization
 Organism consist of one cell only
 All life activities takes place in
single cell
 They may be solitary or colonial.
 Bacteria( unicellular prokaryote)
 Solitary unicellular eukaryotes are
Amoeba, Chlaymydomonas,
Paramecium, Euglena etc.
 In a colony, cells are independent
of one another.
  No coordination with each other
for survival.
 Prokaryotic colonies are Nostoc,
Ocillatoria etc
 Eukaryotic Colonies are volvox etc.
2- Multicellular Organization
 Made up of many cells.
 Organized into tissues and organs
 Cells depend on each other
 Eg. Humans, frog, Mustard plants
etc.
Social Level of Organization:
 Interactions among organisms
 Pattern of life
 Social Behaviour
 Habitat of Organisms.
 There are following levels.
1. Specie Level:
 Very similar organism
 Can breed with one another
 Produce fertile offspring in natural conditions
 Same no. of chromosomes.
 Such as Homo sapiens, Zea mays etc.
2. Population Level:
 Group of individuals of same species
 In a given area
 At same time
Eg
(i) Grass population in a lawn
(ii) Fish population in a pond
(iii) Frog population in pool
 Etc.
3. Community Level:
 Different populations
 Interacting with each other
 In same habitat
 Dynamic collections
 One population may increase while other may
decrease
Types of interactions
(i) Predation
(ii) Parasitism
(iii) Commensalism
(iv) Mutualism
(v) Competition
Etc.
4. Ecosystem Level:
 Community with it physical environment
 Community with non living surrounding.
 Eg biome
Biome:
The largest regional bio geographical unit of
life on earth.
Eg. Tropical rain forest, tundra, coniferous
forest etc.
5. Biosphere:
 All the ecosystems on earth.
 All the places of earth where life exist
 The part of earth inhabited by living organisms.
6. Ecosphere:
 Biosphere along with the part of earth where
no life exist is called ecosphere.
Solving a Biological Problem:
Biological Problem:
1- A problem created by
2- Living organism
3- Or environmental factors
4- Causes harmful effects
5- On other living ones

Biological Method:
 Scientific Method
 Systematic procedure
 Series of steps/ phases
 Taken by scientists
 To solve biological problem
Steps of Biological Method:
1. Detection of biological problem
2. Observation
3. Data
4. Hypothesis
5. Experiments
6. Result/Conclusion
7. Theory
8. Scientific Law
1. Detection of biological problem
 Selection of problem
 Detect carefully
 Use five senses i.e.,
 Vision
 Hear
  Touch
 Taste
 Smell
 Know about nature of problem
2. Observations
 First phase
 Keen understanding of problem
 Uses all sources to get data.
Data: Collection of information
Two types
1 Qualitative Observation:
 Deals with qualities
 Properties
 Eg, knowing about type of disease
 Or atmosphere of surrounding
2 Quantitative Observations:
 Deals with number
 Or quantity
Eg,
Number of diseased people,
Biodiversity of organisms etc.
3. Hypothesis: