Chapter 2 : Biological Classification

What is biological classification?

What is biological classification?

The process of grouping organisms based on certain similarities.

Who proposed the two-kingdom classification system?

Carl Linnaeus

What were the limitations of the two-kingdom classification system?

It did not distinguish between eukaryotes and prokaryotes, unicellular and multicellular organisms, and photosynthetic and non-photosynthetic organisms.

What are the five kingdoms in the five-kingdom classification system?

Monera, Protista, Fungi, Plantae, and Animalia

Criteria for five kingdom classification

Cell structure, Body organisation, Mode of nutrition, Reproduction, Phylogenetic relationship

Kingdom Monera includes

Archaebacteria, Eubacteria.

Archaebacteria Include

Halophiles, Thermoacidophiles, Methanogens

Living conditions for (1)Halophiles (2)Thermoacidophiles, (3)Methanogens

(1)Extreme Salty areas (2)Hot springs (3)Marshy areas&guts of ruminent animals

Explain Features&Function of Cyanobacteria(blue-green algae) with examples

Photosynthetic autotrophs, unicellular, colonial, filamentous. Cells covered with mucilaginous sheath.Function - Fix atmospheric nitrogen in specialized cells called heterocysts.eg:Nostoc&Anabaena

Function of Chemosynthetic bacteria

Oxidise compounds like Nitrites,Nitrates&ammonia. Energy released during this process is used for ATP synthesis.

Diseases caused by bacteria

Cholera,Typhoid, Tetanous(In humans),Citrus canker(In plants)

Kingdom Protista Includes

Chrysophytes, Dinoflagellates, Euglenoids, Slime moulds& Protozoans

Who proposed the five-kingdom classification system?

R.H. Whittaker

What categories are Bacteria grouped under based on their shape

Coccus (Spherical), Bacillus (Rod), Vibrio (Coma), Spirillum (Spiral)

Usage of Methanogens

Produce methane from cow dung,hence it is used in the production of biogas

What is Algal bloom?

Excessive growth of cyanobacteria in polluter water bodies is called algal bloom

Uses of bacteria

-Production of curd from milk

-Production of antibiotics

-Helps in nitrogen fixation of leguminous plants

Explain Chrysophytes

Includes Diatoms&Desmids(golden algae)

Desmids are chief producers of the ocean

Cell wall made of silica thus indestructable

What is Diatomaceous earth? Uses?

Cell wall deposits of Diatoms over millions of years form the Diatomaceous earth.

-Used in polishing

-Filtration of oil and sugar

-Used as fire retardant

What is Red tide?

Excessive growth of red dinoflagellate(Gonyaulax) gives red colour to the sea.This is known as red tide. Toxins released during red tide may kill aquatic organisms.

Features of Euglenoids & Example

Have a Protein rich body layer is called Pellicle which gives flexibility to the body.In presence of sunlight - Photosynthetic, Deprived of sunlight - heterotrophic

Eg : Euglena

Features of Slime moulds

Ancestors of Fungi, Saprophytic protists, During favourable condition the form an aggregation called Plasmodium

What are the major groups of Protozoans with example

(1) Amoeboid protozoans eg: Amoeba,Entamoeba

(2) Flagellated protozoans eg: Trypanosoma (causes African sickness)

(3) Ciliated protozoans eg: Paramecium

(4) Sporozoans eg: Plasmodium (causes Malaria)

What is Mycelium?

Network of hyphae in fungi is known as Mycelium

State the 3 stages of Sexual Reproduction

(1) Plasmogamy - Fusion of protoplasm

(2) Karyogamy - Fusion of two nuclei

(3) Dikaryophase - The condition where, After plasmogamy the two nuclei may remain as such without fusion

What are the criteria for Fungal classification?

Morphology of mycelium, Mode of spore formation & Fruiting bodies

Name the classes of Fungi

Phycomycetes, Ascomycetes, Basidiomycetes & Deuteromycetes

Give the Mycelium, Fruiting Body, Asexual spore, Sexual spore and Examples for Phycomycetes

Mycelium - Coenocytic

Fruiting body - Absent

Asexual spore - Zoospores

Sexual spore - Zygospores

Eg: Rhizopus, Albugo, Mucor

Give the Mycelium, Fruiting Body, Asexual spore, Sexual spore and Examples for Ascomycetes

Mycelium - Septate

Fruiting body - Ascocarp

Asexual spore - Conidia

Sexual spore - Ascospores

Eg: Penicillium, Yeast, Aspergillus, Claviceps, Neurospora

Give the Mycelium, Fruiting Body, Asexual spore, Sexual spore and Examples for Basidiomycetes

Mycelium - Septate

Fruiting body - Basidiocarp

Asexual spore - Absent

Sexual spore - Basidiospores

Eg: Agaricus, Puccinia, Ustilago

Give the Mycelium, Fruiting Body, Asexual spore, Sexual spore and Examples for Deuteromycetes

Mycelium - Septate

Fruiting body - Absent

Asexual spore - Conidia

Sexual spore - Absent

Eg: Alternaria, Colletotrichum, Trichoderma

Why are Deuteromycota called the "imperfect fungi"?

Because they lack perfect or sexual stage.When their sexual stages are known they are moved to either Ascomycetes or Basidiomycetes.

Examples for Insectivorous plants & Parasite

Insectivorous plants - Venus fly trap, Bladderwort

Parasite - Cuscuta

Who discovered that certain microbes cause mosaic disease in Tobacco plants?

Dimitri Ivanowsky

What is the contributions of M W Beijerinek & W M Stanley

M W Beijerinek : Leaf extract from a mosaic affected plant can cause disease in healthy plants

W M Stanley : Crystallised virus

What is Capsid? What is it made up of?

Viruses have a genetic material protected in a protein coat called Capsid. Capsid is made up of many sub units called Capsomeres. Capsomeres are arranged in helical or polyhedral geometric forms.

Viruses which attack bacteria are called

Bacteriophages

Diseases caused by viruses

AIDS, Mumps, Small pox, Herpes, Influenza

What are the symptoms of viral disease in plants

Mosaic formation, Leaf rolling&curling, Yellowing, Vein clearing ,Dwarfing and Stunted growth

Explain Lichen

Symbiotic association between Algae and Fungi, Pollution indicators

Algal component - Phycobiont

Fungal component - Mycobiont

Algae prepare food for Fungi and Fungi provide shelter and absorb mineral nutrients and water.

What is Mycorrhiza?

A symbiotic association between Fungus and roots of higher plants.

Explain Viroids, Discovered by & Disease

Free infectious RNA, Have no protein coating

Discovered by T O Diener

Disease : Potato spindle tuber disease

What are Prions & Diseases caused by it.

Prions are abnormally folded protein similar to the size of viruses.They cause

Spongiform Encephalopathy(BSE) aka Mad cow disease in cattles

Cr-Jacob disease(CJD) in humans