Biological Classification [NCERT] Flashcards
who was the first to give a scientific basis for classification?
Aristotle
aristotle’s classification was based on?
morphological characters
aristotle classified plants into?
trees. herbs & shrubs.
Aristotle divided animals into:
those who have red blood & those who don’t.
two kingdom classification did not distinguish between:
the eukaryotes and prokaryotes, unicellular and multicellular organisms
and photosynthetic (green algae) and non-photosynthetic (fungi)
organisms.
who proposed 5 kingdom classification?
R.H. Whittaker.
kingdoms defined in 5 kingdom classification?
Monera, Protista, Fungi, Plantae
and Animalia.
The main criteria for classification used by R.H. Whittaker ?
1. cell structure 2. body organisation, 3. mode of nutrition, 4. reproduction 5. phylogenetic relationships.
sole members of kingdom monera?
bacteria
Bacteria are grouped under what categories based on their shape?
the
spherical Coccus (pl.: cocci), the rod-shaped Bacillus (pl.: bacilli), the
comma-shaped Vibrium (pl.: vibrio) and the spiral Spirillum (pl.: spirilla)
_________ as a group show most extensive metabolic diversity?
bacterias
bacteria that live in some of the most harsh habitats
Archaebacteria
halophiles??
bacterias living in extremely salty areas
thermoacidophiles?
bacterias living in hot springs
methanogens
bacterias living in marshy areas
archaebacteria differ from other bacteria in?
they have a different cell wall structure and this feature is responsible for
their survival in extreme conditions.
________ present in the gut of several ruminants?
methanogens
methanogens are responsible for? (related to ruminants)
production of biogas from the dung of these animals
eubacteria are characterised by the presence of?
~ a rigid cell wall
~ if motile,, a flagellum
cyanobacteria has what type of chlorophyll?
chlorophyll a (similar to green plants and are photosynthetic autotrophs)n
cyanobacteria are
unicellular, colonial or filamentous,
freshwater/marine or terrestrial algae.
colonies are generally surrounded by?
gelatinous sheath
Some of
these organisms can fix atmospheric nitrogen in
specialised cells called:
Heterocysts, e.g., Nostoc and
Anabaena.
Chemosynthetic autotrophic bacteria oxidise …………………??
oxidise various inorganic substances such as
nitrates, nitrites and ammonia and use the released
energy for their ATP production.
___________ play a great role
in recycling nutrients like nitrogen, phosphorous,
iron and sulphur.
chemosynthetic autotrophic bacterias
heterotrophic bacteria are helpful in :
helpful in making curd from milk,
production of antibiotics, fixing nitrogen in legume roots etc.
some bacterial diseases :
Cholera, typhoid, tetanus, citrus canker
bacteria mainly reproduce by?
FISSION
bacterias under unfavourable conditions form? ,
spores
sexual reproduction in bacteria by?
by adopting a
primitive type of DNA transfer from one bacterium
to the other.
The ____________ are organisms that
completely lack a cell wall
Mycoplasma
smallest living cells?
Mycoplasma
can Mycoplasma survive without oxygen?
yes
all single celled eukaryotes are placed under
protista
are the boundaries of PROTISTA well defined?
no
members of protista are primarily ____________
aquatic
which kingdom forms a link with the others dealing with plants, animals
and fungi.
protista
the protistan cell body contains……………
a well defined
nucleus and other membrane-bound organelles. Some have flagella or
cilia.
protista reproduce asexually and sexually by
a process involving
cell fusion and zygote formation.
protista includes
- Chrysophytes,
- Dinoflagellates
- Euglenoids,
- Slime moulds
- Protozoans
Chrysophytes
includes
diatoms and golden algae (desmids)
chrysophytes are found in…
in fresh water as well as in marine environments
cell walls in diatoms form…….
In diatoms the cell walls form two thin overlapping shells,
which fit together, The walls are embedded with silica
and thus the walls are indestructible.
…………………….. have left behind
large amount of cell wall deposits in their habitat
diatoms
this accumulation of diatoms’ cell wall deposits over
billions of years is referred to as
‘diatomaceous earth’.
‘diatomaceous earth’ is used in _____________
in polishing, filtration of oils and syrups
chief producers in the oceans?
diatoms
Dinoflagellates may appear……………………
They appear yellow, green, brown, blue or red depending
on the main pigments present in their cells.
Dinoflagellates are mostly ……
mostly marine and photosynthetic.
cell wall of dinoflagellates have ………………………..
stiff cellulose plates on the outer surface
flagella in dinoflagellates……………
Most of
them have two flagella; one lies longitudinally and the
other transversely in a furrow between the wall plates.
red dinoflagellates cause ……………….. after going through rapid multiplication
red tides ( sea appears red)
example of red dinoflagellates
Gonyaulax
majority of euglenoids are
fresh water organisms found in
stagnant water
instead of cell wall, euglenoids have
pellicle (a protein rich layer)
pellicle makes their body
flexible
euglenoids have ____ flagella
2 flagella; a short & long one
euglenoids are ________ in presence of sunlight
photosynthetic
when
deprived of sunlight euglenoids behave like
heterotrophs by
predating on other smaller organisms.
pigments of euglenoids are identical to those present in
higher plants.
example of euglenoids
euglena
slime moulds show what type of nutrition
saprophytic
Under suitable conditions, slime moulds form an
aggregation called
plasmodium which may grow and
spread over several feet
During unfavourable conditions,
the plasmodium ________________________
differentiates and forms fruiting bodies
bearing spores at their tips.
all protozoans are
heterotrophs & live as predators or parasites
4 major groups of protozoans :
- AMOEBOID PROTOZOANS
- Flagellated protozoans
- Ciliated protozoans
- Sporozoans
marine amoeboid protozoans have ________ shells
silica shells on their surface
a parasitic amoeboid protozoa
entamoeba
a parasitic flagellated protozoa
Trypanosoma ( causes sleeping sickness )
example of Ciliated protozoans
paramoecium (has thousands of cilia)
have an infectious spore- like stage in their life
sporozoans
example of sporozoans
Plasmodium
malarial parasite
wheat rust causing fungi
puccinia
fungi are mainly _______
filamentous, with a few exceptions like unicellular yeast
what are hyphae?
fungi consist of long, slender thread-like structures
called hyphae.
network of hyphae is called
mycelium
some hyphae are continuous tubes filled with multinucleated cytoplasm, what are these called?
coenocytic hyphae.
cell wall of fungi made of
chitin & polysaccharides
fungi live in association with algae as
lichens
fungi live with roots of higher
plants as
mycorrhiza.
vegetative reproduction in fungi by
fragmentation, fission and budding
asexual reproduction in fungi by
spores called conidia, or sporangiospores or zoospores
sexual reproduction
in fungi by
by oospores, ascospores and basidiospores
the various spores in fungi are produced in
distinct structures called fruiting bodies.
steps of sexual cycle in fungi
(i) Fusion of protoplasms between two motile or non-motile gametes
called plasmogamy.
(ii) Fusion of two nuclei called karyogamy.
(iii) Meiosis in zygote resulting in haploid spores
dikaryon ?
in some
fungi (ascomycetes and basidiomycetes), an intervening
dikaryotic stage (n + n, i.e., two nuclei per cell) occurs;
such a condition is called a dikaryon and the phase is
called dikaryophase of fungus
mycelium in phycomycetes `
aseptate & coenocytic
Members of phycomycetes are found in what kind of habitats
aquatic habitats
and on decaying wood in moist and damp places or as
obligate parasites on plants.
asexual reproduction in phycomycetes takes place by
zoospores (motile) & aplanospores (non-motile).
examples of phycomycetes
Mucor, Rhizopus (the bread
mould) and Albugo (the parasitic fungi
on mustard).
ascomycetes commonly called as
sac-fungi
mycelium of ascomycetes
branched and septate.
asexual repro in ascomycetes by
The asexual spores are conidia produced
exogenously on the special mycelium called conidiophores
conidia on germination produce
mycelium
sexual repro in ascomycetes by
Sexual spores are called ascospores
which are produced endogenously in sac like asci (singular ascus). These
asci are arranged in different types of fruiting bodies called ascocarps
examples of ascomycetes
aspergillus, Claviceps and Neurospora
Neurospora is used extensively in
biochemical and genetic work
edible members of ascomycetes/ considered delicacies
morels and truffles
Commonly known forms of basidiomycetes are
mushrooms, bracket fungi
or puffballs.
basidiomycetes grow in/on
They grow in soil, on logs and tree stumps and in living
plant bodies as parasites, e.g., rusts and smuts.
mycelium of basidiomycetes
branched & septate
reproduction in basidiomycetes ……..
asexual spores are generally not found, but vegetative
reproduction by fragmentation is common. The sex organs are absent,
but plasmogamy is brought about by fusion of two vegetative or somatic
cells of different strains or genotypes
Karyogamy and meiosis take
place in the______ producing ____ basidiospores.
basidium ; 4
how are basidiospores produced
exogenously produced on the basidium
The basidia are
arranged in fruiting bodies called
basidiocarps
members of basidiomycetes
Agaricus (mushroom) , Ustilago (smut) and Puccinia (rust
fungus).
deuteromycetes commonly known as
imperfect fungi (( because only the asexual or vegetative phases of these fungi are known. ))
he deuteromycetes reproduce only by
asexual spores
known as conidia
The mycelium of deuteromycetes
is
septate and branched
large number of deuteromycetes are
decomposers of litter and help in mineral cycling.
examples of deuteromycetes
Alternaria, Colletotrichum and Trichoderma
Kingdom Plantae includes
all eukaryotic chlorophyll-containing
organisms commonly called plants
A few members of plantae partially
heterotrophic such as the
insectivorous plants ( venus fly trap ) or parasites ( cuscuta)
animalia is characterised by
heterotrophic eukaryotic organisms
that are multicellular and their cells lack cell walls.
holozoic nutrition in
kingdom animalia
reserve food in animalia
glycogen or fat
what are viruses?
The viruses are non-cellular organisms that are
characterised by having an inert crystalline structure outside the living cell.
the name virus means
venom or poisonous fluid
virus was named by
Dmitri Ivanowsky (1892)
W.M. Stanley (1935)
showed that
viruses could be crystallised and crystals consist largely of
proteins.
genetic material in virus
either DNA or RNA
can a virus contain both DNA & RNA
no
A virus is
a _____________ and the genetic material is infectious.
A virus is
a nucleoprotein
viruses
that infect plants
have single stranded RNA
viruses that infect animals
have
either single or double stranded RNA or double stranded DNA.
Bacterial viruses or bacteriophages (viruses that infect the bacteria)
are
usually double stranded DNA viruses
protein coat of virus called
capsid
capsid is made up of
small subunits called capsomeres (( protects the
nucleic acid ))
These capsomeres are arranged in
helical or polyhedral
geometric forms.
diseases caused by viruses
mumps, small pox, herpes and influenza. AIDS. In plants, the symptoms can be 1. mosaic formation, 2. leaf rolling and curling, 3. yellowing 4. vein clearing, 5. dwarfing and stunted growth.
viroids discovered by
T.O. Diener
viroids cause
potato spindle tuber disease
RNA of viroids was of
low molecular weight
SMALL NOTE ABOUT VIROIDS
infectious agent that
was smaller than viruses. It was
found to be a free RNA; it lacked the protein coat that is found in viruses,
certain infectious neurological diseases
were found to be transmitted by
an agent consisting of abnormally folded
protein called PRIONS.
prions have size
similar to viruses
prions cause
bovine spongiform
encephalopathy (BSE) commonly called mad cow disease in cattle and
its analogous variant Cr–Jacob disease (CJD) in humans.
what are lichens
Lichens are symbiotic associations i.e. mutually useful
associations, between algae and fungi.
algal component of lichens is called
phycobiont ( autotrophic )
fungal component of lichens is called
mycobiont (heterotrophic)
role of algae in lichen
prepare food for fungi
role of fungi in lichen
provide shelter and absorb mineral nutrients and water
how do lichens indicate pollution?
they do not grow in polluted areas
