Prokaryotes which have the ability to grow in extreme conditions like volcano vents, hot springs and polar ice caps are called extremophiles. They have adaptations such as :
1. Capacity to synthesize their food without sunlight and oxygen by utilizing hydrogen sulphide and other chemicals from the volcanic vents.
2. Some of them produce methane (Methanogens).
3. Some live in salty environments (Halophiles).
4. Some are thermoacidophiles which thrive in acidic environments and at high temperature.

1. The main criteria of systematics is identifying, describing, naming, arranging, preserving and documenting the organisms.
2. Evolutionary history of the species and the environmental adaptations and interrelationship between species are also being investigated in systematics

The basic need for classification is:
1. To identify and differentiate closely related species.
2. To know the variation among the species.
3. To understand the evolution of the species.

(i) Yes we can use recent molecular tools to identify and classify organisms.
(ii) Eg: Automated species identification tools electron microscopy (for cellular organelles and molecular structures by neo taxonomical tools) behaviour of organisms by ethology of taxonomical tools and development of electronic digital images and description by INOTAXA or e- Taxonomic resources.

(i) This family consists of more than one species in the genus it is known as polytypic genus.
(ii) Species are intrageneric
(iii) A single genus is Felis which has a number of closely related species.
(iv) Different species of a single genus show the same morphological characteristics but their behavior varies
(v) Eg: Felis domestica (Domestic cat)
Felis margarita (Jungle cat)
Felis silvestris (Wild cat)

Probiotics	Pathogenic bacteria
Probiotic bacteria are beneficial.	Pathogenic bacteria are harmful.
Probiotic bacteria may be decomposers, photosynthetic and few may be pathogenic.	All are pathogenic and causing diseases.

The study of evolution of organisms based on evolutionary and genetic relationships among organisms, led to the emerge of phylogenetic classification or cladistics.

Based on the presence or absence of red blood he classified the animals into two as Enaima with blood and those without blood as Anaima.

Taxonomy (G. taxis- arrangement; nomos-law) is the science of arrangement of living organisms along with classification, description, identification, and naming of organisms which includes all flora and fauna including microorganisms of the world. The word taxonomy was coined by Augustin Pyramus de Candole (1813).

1. The presence of a large number of species in a particular ecosystem is called 'biological diversity' or in short' biodiversity'.
2. The term biodiversity was first introduced by Walter Rosen (1985), and defined by E.D. Wilson.

Mule is sterile and cannot yield its offsprings because it is born from the cross made between different species like Male Donkey and Female Horse.

(i) Definition: The system emphasizes the separation of prokaryotes into two domains, Bacteria and Archaea and 3^rd Eukarya.
(ii) Carl woese (1977) divided Domains into three types. They are
a. Domain Archaea
b. Domain Bacteria and
c. Domain Eukarya
a) Domain Archaea:
Eg: Single celled organisms (prokaryotes)
(i) They live under extreme climatic conditions
(ii) As they have the ability to grow under extreme conditions like volcano vents, hot springs and polar ice caps, the prokaryotes are called as extremophiles
(iii) Chemosynthetic bacteria can synthesize food by the oxidation of inorganics like hydrogen sulphide (H₂S)
(iv) Methane producing organisms are methanogens
(v) Organisms living in salty environment are halophiles
(vi) Organisms live under higher temperatures are thermoacidophiles.
b) Domain Bacteria:
(i) Members are prokaryotes like bacteria
(ii) Cells have no definite true nucleus
(iii) DNA is large, circular, coiled, doubled stranded and naked
(iv) Histones are absent
(v) No membrane bound organelles
(vi) Sub-organelles like 70s type of ribosomes are membranous
(vii) Cell wall is made up of peptidoglycans
(viii) Many bacteria are decomposers (eat on dead decaying organisms)
(ix) Some are photosynthetic and pathogenic
(x) The beneficial probiotic and harmful pathogenic bacteria are diversely populated
(xi) Blue-green algae (prokaryotic plants) like cyanobacteria are photosynthetic they release O₂
(xii) Such bacteria balance atmospheric O₂ level and these were previously anaerobic and become aerobic during the advancement of changes of geographical periods.
c) Domain Eukarya:
(i) All animals belong to Eukarya
(ii) True nucleus and membrane bound organelles and sub-organelles are found-
(iii) DNA in the nucleus is arranged as a linear chromosome
(iv) Histones proteins are present
(v) Ribosomes are of 80s type but 70s type of ribosomes are found in chloroplasts and mitochondria (like in prokaryotes)
(vi) Animals in this domain are classified into Protista, Fungi, Plantae and Animalia

Rules of Nomenclature:
1. The scientific name should be italicized in printed form and if handwritten, it should be underlined separately.
2. The generic name's (Genus) first alphabet should be in uppercase.
3. The specific name (species) should be in lowercase.
4. The scientific names of any two organisms are not similar.
5. The name or abbreviated name of the scientist who first publishes the scientific name may be written after the species name along with the year of publication. Eg: Lion-Felis leo Linn., 1758 or Felis leo L., 1758.
6. If the species name is framed after any person's name the name of the species shall end with i, ii or ae.
7. Eg: A new species of a ground-dwelling lizard (Cyrtodactylus) has been discovered and named after Scientist Varad Giri, Cyrtodactylus varadgiri.

(i) The word biology itself is a greek word where bios means life and logos means study.
(ii) The role for latin and greek words are used in classification especially in Binomial classification.
(iii) Named to understand and remember the scientific names of organisms.
(iv) The Binomial nomenclature (L.Bio-two; Nomen-Name) Vector animals and Plants is largely derived from latin and Greek words.
(v) Binomial nomenclature was originally codified in the works of Carolus Linnaeus (1753), Species Plantarum.
(vi) Latin is now used by classical scholars, certain purpose in botany and in the medicine field.
(vii) The purpose is to give every species a distinct name which will be recognized everywhere became common names abundant species vary from country to country or even from region to region within a country.
(viii) using latin and greek forms simply refresh the main language of science when this system was invented.
(ix) Other languages words now used are given grammatical endings derived from the classical languages. Ex: Blakea atton boroaghi.