BIOLOGICAL CLASSIFICATION
 |
| biological classification class 11 notes for neet |
SYSTEMS OF CLASSIFICATION
Earliest Classification was given by Aristotle. Divided plants into herbs, shrubs and trees. Animals into those with RBC’s and those who do not have it.
Two kingdom classification :Given by Carolous Linnaeus − Plant kingdom and Animal kingdom.
Five kingdom classification : By R. H. Whittaker. Monera, Protista, Fungi, Plantae and Animalia are the five kingdoms.
Kingdom Monera
Found in
- normal habitat
(air, water, soil)
-unfavorable conditions
(High temperature, desert, snow, deep sea, gut of animal, as a parasite)
Bacteria
- Bacteria are the sole member.
-unicellular
-Shape of bacteria :
Coccus (spherical), Bacillus (rod-shaped), Vibrio (comma shaped) and sprillum (spiral shaped).
- Nutrition
1) Autotrophic
a) chemo autotrophic
b) photoautotrophic- i) oxygenic
ii) anoxygenic
2) Hetero trophic
a) saprophyte
b) parasitic
c) symbiotic
-Reproduction
1) asexual reproduction (fission, spore formation)
2) sexual reproduction ( some primitive method of DNA transfer - transformation, conjugation, transduction)
Archaebacteria
->Differs from bacteria having different cell wall structure.
->They live in most harsh habitats
->Halophiles (extreme salty areas)
->Thermoacidophiles (in hot springs)
->Methanogen (marshy area)
->Methanogen are also found in the gut of ruminant(cow, buffaloes)and responsible for production of methane (biogas).
Eubacteria
- true bacteria
-Rigid cell wall and if motile a flagellum
- Also known as blue green algae or Cyanobacteria.
- Cyanobacteria are photosynthetic autotrophs.
- Cyanobacteria have chlorophyll a pigment
- Cyanobacteria are unicellular, colonial or filamentous, marine and terrestrial algae.
- Colonies are surrounded by gelatinous sheath.
- Often form blooms in polluted water bodies
- Some of these can fix atmospheric nitrogen by specialized cells called heterocyst, e.g. Nostoc and Anabaena.
- Chemosynthetic autotrophs: Oxidize various inorganic substances like nitrates/nitrites, ammonia and use released energy for their ATP production.
Heterotrophic bacteria
- Most abundant in nature
- Mostly decomposer
- Helpful in making curd from milk
- Production of antibiotics
- Symbiotically associated with leguminous plant and fix nitrogen.
- Some are pathogen causing diseases like cholera ( Vibrio cholerae),typhoid (Salmonella typhi), tetanus (Clostridium tetani), pneumonia (Streptococcus pneumoniae), citrus canker (Xanthomonas citri)
- Bacteria reproduce mainly by fission, also produce spore in unfavorable condition.
Reproduce sexually by transfer of DNA form one bacteria to other, the process called conjugation.
Mycoplasma
->Completely lack cell wall.
->Smallest living cells.
->Can survive without oxygen.
->Pathogenic in animals and plants.
Kingdom Protista
->All are unicellular and eukaryotic.
->Mostly aquatic, can live in moist places.
->Forms a link between plants, animals and fungi.
->The cell contain nucleus and membrane bound organelles.
Chrysophytes
->Includes diatoms and golden algae (desmids)
->Found in freshwater or marine water.
->Mostly planktonic ( passive swimmer)
->Photosynthetic.
->Cell walls overlap to fit together like a soap box.
->Cell wall contains silica hence indestructible.
->Their accumulation forms ‘Diatomaceous Earth’.
->Used in polishing, filtration of oils and syrups.
->Diatoms are the chief ‘producers’ in the oceans.
Dinoflagellates
->Marine, photosynthetic.
->Cell wall has stiff cellulose plates.
->Appears yellow, green, brown, blue or red depending on the pigments.
->Have two flagella − one longitudinal and other transversely in a furrow between wall plates.
->Red Dinoflagellates (Gonyaulax) form red tides.
Key words
class 11 biology chapter 2 biological classification notes
biological classification class 11 notes for neet
ncert biology class 11 chapter 2 notes
Youtube channel : Suman Pratihar
Also visit :
the living world class 11 notes for neet
Can I crack neet without coaching in first attempt?
How to prepare for neet examination at home without coaching
How to study NCERT Biology for neet exam preparation.