Chapter 2 Biological Classification

Systems of Classification

Systems of Classification

Artificial, natural and phylogenetic

Who proposed 2 kingdom classification? Which were the 2 kingdoms?

Carolus Linnaeus (1758) Planta and Animalia

What were the drawbacks of 2 kingdom classification?

It does not distinguish between 1) Unicellular and multicellular 2) Prokaryote and Eukaryote 3) Autotrophic and Heterotrophic

Who proposed 3 kingdom classification? Which were the 3 kingdoms?

Ernst Haeckal (1866) Plant , Animalia and Protista

Who proposed 4 kingdom classification? Which were the 4 kingdoms?

Copeland (1956) Plant , Animalia , Protista and Monera

Who proposed 5 kingdom classification? Which were the 5 kingdoms?

R. H Whittaker (1969) Plant , Animalia , Protista, Fungi and Monera

Who proposed 6 kingdom classification? Which were the 6 kingdoms?

Carl Woese, Gray and Doolittle, Plant , Animalia , Protista, Fungi , Archaebacteria and Eubacteria (Monera)

What are the three domains of life? Who proposed it and what was it based on?

Three domains - Archaea, Bacteria and Eukarya. It was proposed by Carl Woese and was based on genetic analysis of 16s RNA.

What was the criteria for 5 kingdom classification ?

Complexity of - 1) Cell structure 2) Body organization 3) Nutrition 4) Reproduction 5) Phylogenetic relationships

Which kingdoms are unicellular and which are multicellular?

Monera and Protista are unicellular . Plantae, Fungi and Animalia are multicellular.

Which kingdoms are prokaryotic and which are eukaryotic?

Monera is Prokaryotic. Protista,Plantae, Fungi and Animalia are eukaryotic.

What are the basic properties of Monera?

unicellular, Prokaryotic,
nutrition - hetero or auto,
cell wall - amino acids + non - cellulosic polysaccharides (peptidoglycan),
Ecologically - producers or decomposers.

Who discovered Bacteria and who coined the term bacteria?

It was discovered by Anton Von Leewenhoek. and the term was coined by Ehrenberg.

What are all the structures present in the structure of eubacteria?

Glycocalyx, Cell wall, cell membrane, Flagella, Fimbride, Pilli , Mesosome, Nucleoid/Genophore, Plasmid, Ribosome, Inclusion bodies and Chromatophore,

What is the Glycocalyx ?

Present in Eubacteria -
It is an Outer mucilaginous covering around bacteria made of heteropolysaccharides which protects it from the external environment.
It can be capsule form (tightly arranged) or slime layer form (loosely arranged)

What is the cell wall in eubacteria made up of?

It is made up of Peptidoglycan/Murein/Mucopeptide and consists of amino acids and sugar units.

What is NAG and NAM?

It is present in cell wall of eubacteria. NAG (N - acetyl glucosamine) and NAM (N - acetyl muramic acid)

What is the cell membrane of Eubacteria made up of?

Made up of lipid , protein and polysacchride (like in eukaryotes)
Respiratory enzymes and Sterol compound Hopanoid is present in membrane.

What is flagella? what does it consist of ?

Flagella is a locomotory outgrowth from cell membrane made up of flagellin protein. It consists of basal body, hook and filament.

What are fimbride?

They are small hair like outgrowth which heelp bacterium to attach to substratum.

What are Pili?

They are small hollow outgrowths which are involved in making conjugation tubes between bacterial cells.

What are mesosomes?

They are internal folds of the cell membrane in the cytoplasm

what are the functions of mesosome?

1) cellular respiration 2) DNA replication 3) cell wall formation 4) increase surface area

What is nucleoid/genephore?

It is a primitive , genetic material of bacterial cell which is circular, ds naked DNA.

What are Plasmids?

They are extrachromosomal , circular, ds DNA which contains genes for antibiotic resistance, genetic varaition and feritility factor etc.

Which is only cell organelle in bacteria?

Ribosomes. They are 70s (50 + 30s).
Sometimes many ribosomes attach on single mRNA strand to form Polysome/Polyribosome.

What are inclusion bodies?

They are small storage granules in cytoplasm.
eg - Glycogen granules, Lipid Granules,
Cyanophycean granules and Gas vacuoles

What are Chromatophores?

They are specialized, internal , membraneous, sac like structures present in photosynthetic bacteria which carry pigments like Bacteriochlorophyll, bacteriovirdin etc.

What is the classification of bacteria based on shape?

1) Coccus (spherical),
Bacillus (rod shaped),
Vibria (comma shaped),
Spirillum (spirally coiled)

What is the classification of Flagella based on number?

1) Monotrichous - single flagella at one end 2)Amphitrichous - single flagella at both ends 3)Cephalotrichous- Group of flagella at one end 4)Lophotrichous- Group of flagella at both end 5)Petritrichous- flagella all around the body
6)Atrichous - Flagella is absent

Types of nutrition in bacteria

1) Autotrophic - Photosynthetic or chemosynthetic
2) Heterotrophic - Saprophytic, Symbiotic or Paraasitic

What is a unique fact about bacteria?

Bacteria shows most extensive metabolic diversity.

write a short note about photosynthetic bacteria?

They prepare food in presence of light.
Types -
1) Oxygenic - cyanobacteria
2) Anoxygenic - Green sulphur bacteria and purple bacteria

write a short note about chemosynthetic bacteria

They prepare organic substances from organic substances and do it in presence of energy from oxidation of chemicals.
eg - nitrifying bacteria - Nitrosomonas,
nitrococcus, Nitrobacter
*Iron bacteria , sulphur oxidising bacteria

write a short note about symbiotic nature in bacteria

bacteria live in mutual relationship with others organisms.
eg - Rhizobium lived with root nodules of legumes
E. coli live in human intestine.

write a short note about saprophytic nature in bacteria

They obtain food from dead remains. eg - Psuedomonas

write a short note about parasitic nature in bacteria

they obtain nourishment from other living beings and are pathogenic since they cause diseases.

Examples of parasitic bacteria.

1_ Plant - Xanthomonas citri - Citrus canker
2 - Animmal - Bacillus anthracis - anthrax
3- humans - vibrio cholerae - cholera
4_ humans - clostridium tetani- tetanus
5 -humans - salmonella typhi - typhoid

How does asexual reproduction take place in bacteria?

Binary fission. here cell divides, nucleoid divides and constriction forms at central region.

Write a short note about spores in bacteria

endospore - thick-walled asexual spores resistant to adverse conditions, when it is a favorable condition, cell wall ruptures and grows into new fungi.

Write a short note about sexual reproduction in bacteria

gamete formation and true sexual rep is absent. here only primitive, recombination occurs.

three types of sexual reproduction in bacteria

1) conjugation - transfer of genetic material from one cell to another through tube
2) transformation - involves direct pickup of genetic material from surrounding of dead donor bacterium
3) Transduction - Involces transfer of genetic material from one cell to another due to bacteriphage.

who discovered conjugation?

Lederberg and Tatum in E. coi

who discovered transformation?

griffith in diplococcus pneumoniae

who discovered transduction?

Zinder and Lederberg in salmonella

importance of bacteria

1) decomposition
2) sewage treatment
3) milk to acid
4) regulating n2 cycle
5) source of antibiotic (bacillus subtillis subtilin)
6) source of vitamin (e coli - vit B &K)
7) Source of acid - acetic acid from acetobacter aceti

PROPERTIES OF ARCHAEBACTERIA -

Live in extreme conditions like high salty , high acidic and high temp.

what is the cell wall and cell membrane of archaebacteria made up of ?

cell wall - pseudopeptidoglycan
cell membrane - branched chain lipids
this chemical composition helps them to live in extreme conditions

three types of archaebacteria

1. Methane producing bacteria - Methanogen
occur in marshy places and cow gut
eg - methanobacterium , methanococcus

2. Salt loving bacteria - Halophiles
eg- halobacterium, halococcus

3. Heat and acid loving bacteria - Thermoacidophiles
above 80 C and ph <2. they have special resistant enzymes.
eg - Thermoplasma

write about samllest bacteria?

Mycoplasma - lack cell wall.
discovered by nocard and raux and term given by nowak. causes diseases in plants and animals.
eg - Pleuro pneumonia in cattle,
witches broom disease

What are actinomycetes? (ray fungi)

filamnetous form of fungi which grow in radiating colonies in culture.
eg - frankia( symbiosis with alnus , casuorina) and streptomyces (antibiotics streptomycin and erythromysin)

write a short note on Cyanobacteria / blue green algae

algal like prokaryote,
show oxygenic photosynthesis.
possess pigment, chlorophyll a (green), phycocyanin, phycoerythrin
they can be unicellular, colonial or filamentous
they lack flagella and filamental body is called trichome.
food is cyanophycean starch in granules

Reproduction of archaebacteria

unicellular form- binary fission
filamentous - fragmentation

importance of archaebacteria

1) N2 fixing
a) free living - nostoc , anabaena , oscillatoria , aulosia
b) symbiotic - nostoc with coralloid root
anabaena with azolla

2) source of protein - spriulina

3) causes algal bloom in polluted water bodies and cause 02 depletion

4) Develops red sea - eg - trichodesmium erythreum

feautures of fungi

eukaryotics, multicellular (exp yeast) , cosmopolitan, decomposers,
cell wall made up of chitin
reserve food - glycogen

body of fungi

consists of long , slender , thread like filament structure called hyphae, network of hyphae - mycelium
fungi can either be septate or aseptate or coenocytic

Nutrition of Fungi

heterotrophic
1) saprotrophs - rohizopus, muccus
2) sumbiotic 0 fungi with lichen and mycorrhiza
3_ parasitics puccinia (rust fungi), ustilago (smut fungo)
4) coprophilous - peziza

asexual reproduction in fungi

1) vegetative- fragmentation
2) budding
3) asexual spores - zoospres( have flagella), sporangiospores ( non motile, no flagella) - aplanospores
condiospores - non flagellate , exogenous at tip of hyphae

sexual organs in fungi

here fusion of gametes take place.
sex organs are called gametangium
male - anthredium
female- oogonium/ascogonium

3 sexual processes in fungi

1) plasmogamy
2) Karyogamy
3) Meiosis
occurs in phyco, asco , basidio

fun fact about fungi

in ascomyctes and basidiomycetes, plasmogamy is not immediately followed by karyogamy and here dikaryon stage takes place

classifciation of fungi is based on

mycelium , spore formation and fruiting body

phycomyctes - algal fungi

1) phycomyctes - aquatics/terrestrial
saprophyte/ obligate parasite
mycelium - aseptate and coenocytic
aexual spores - zoospores and aplanospores
sexual spores - oospores or zygospores


eg - rhizopus - bread mould
muccor
albugo - white rust on mustard
phytophthora infestans - late blight of potato

ascomycetes - sac fungi

unicellular (yeast ) or multicellular
saprophytic, parasitic, symbiotics, or coprophilous
mycelium - septate and branched
asexual spores - condiospores
sexual spores - ascospores in ascus sac in ascocarp

classification of ascocarp based on shape

1) apothecium - cup shaped
2) perithecium - flask shaped
3) cleistothecium - closed type

examples of ascocarp

1) yeast - saccharomyses cerviside
2) Pencillium - antibiotic from penicillium notatum in 1929
3) aspergillus
a niger - source of citric acis
a flavus - aflatoxin
4) Neurospores - used for lab research
5) claviceps - ergot fungi. produce hallucinogen LSD
6) Morels - spony mushroom. morchella is edible.
7) truffles - edible
8) peziza - coprophilous

basidiomyctes

saprophyte/ parasite
mycelium -septate and branched
veg- fragmentation
aexual spores - none
sexual rep- sex organs absent,, dikaryon takes place
sexual spores - basidiospore in club shaped basidium in body basidiocarp


eg - agaricus - gill fungi
toad stool - poisonous
puff balls - plycoperson
brackert fungus - polyporous
puccinia - rust fungi
ustilago - smut fungi barley

deuteromyctetes

saprophyte/ parasite
mycelium -septate and branched

aexual spores - condiospores
sexual rep- absent


eg - alternia solani - early blight of potato
colletotrichum falcatum- red rot of sugarcane
trichoderm polysporum - prodece cyclosporin a (medicinal drug)

Importance of fungi

1) source of food
2) source of antibiotic - pencillin
3) fermentaion baking and alcohol
4) source of acid - citric - A. niger
5) Medicinal drug - cyclosporin - A

protista

unicellular, eukaryotics, autotrophic/heterotrophic, cell wall - present or absent
producers/consumers/decomposers
poses cilia and flagella and are mostly aquatic

nutrition in protista

1) Photosynthetic - diatoms, euglena
2) holozoic - amoeba, paramoecium,
3) saprophytic - slime mould
4) parasitic - plasmodium

reproduction in protists

1) asexual - binary fission
2) sexual - involves meiosis, fertilization, zygote formation

types of photosynthetic protistans

chrysophytes, dianoflagellates, and euglena

Chrysophytes

eg 0 diatoms , desmids (golden algae)
foundin fresh or marine ahabiat
flagella absent and they float on water
cell wall - silica rich,
forms soap box - frustule epitheca (big), hypotheca ) small)
common reproduction - binary fission

importnace - diatoms, uses - polishingh filtration , toothpaste

importance of dianofalgellates

1) red tide - gonyalux
2) toxin - gonyalux ( causes psp in human)
3) bioluminiscence

Dianoflagellates (golden brown algae)

mostly marine
colours- yellow, green , blue, brown , red
pigments- chlorophyll a,c, xanthophyll, carotene
cell wall- cellusoic plates
2 flagella - longtitudinal transverse

euglenoids

mostly fresh water,
cell wall absent has flexible protenaceous covering called pellicle.
2 flagella- one long and 1 short
many pigments - chlorophyll a,b, xanthophyll, carotene
mixotrophic nutrition
light sensing - eye spot/stigma
stored food- paramylum granules
reproduction - longtidunical binary fission

slime moulds

saprophytic decomposers
eg - physarum , dictyostelium
lack cell wall in somatic phase, spores have true walls

reproduction in slime moulds

fav - aggreagte of wall less multinucleate protoplasm. called plasmodium.
unfav- plasmodium becomes fruiting body and germinate in fav conditions

protozosan protists

ancestor of animals
they have cilia , flagella, pseudopodia for locomotion
four types - amoeboid, flagellated, ciliated , sporozoans

Amoeboid Protists

predator or parasitic
have pseudopodia
marine forms - have silico shells
eg - amoeba, entamoeba - cause amoebiasis

Flagellated Protozoans

free living or parasite
eg - lesihmania - kala azar
trypnosoma-- african sleeping sickness
hiardia interstinals
trichomonas viginalis- leucorrhaea

What are ciliated protozoans?

They are aquatic
eg - paramoecium (they have micro and macronucleus)
the body cavity has gullet for food cap and steering
reproduction by - transverse binary fission

What are sporozoans?

They have infectious spore-like stages and cause diseases.
eg - plasmodium - malaria
plasmodium vivax and p. falciparum - female anopheles mosquito