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2. Biological Classification Flashcards

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1
Q

Who was the first one to classify? How did he classify plants and animals into?

A
  1. Aristotle was first to classify.
  2. He classified on the basis of simple morphological characteristics (height)
    3.Plants: Herbs, Shrubs, Trees
  3. Animals: Red blood animals and non-red blood animals.
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2
Q

Who was the second one to classify? What are the groups he classified into? What was this classification called as?

A
  1. Carolus Linnaeus was the second one.
  2. He classified 2 kingdoms: Kingdom Plantae and Animalia with plants and animals resp.
  3. This type of classification was called as Two-kingdom classification.
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3
Q

What are the demerits of Two- Kingdom classification?

A

The demerits of two kingdom classification are:
1. Didn’t distinguish b/w eukaryotes & prokaryotes.
2. Didn’t distinguish b/w unicellular & multicellular.
3. Didn’t distinguish b/w photosynthetic (green algae) & non-photosynthetic (fungi).
4. Many organisms didn’t fall into either of the category.

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4
Q

Who proposed Five kingdom classification? Name the five kingdoms.

A

R.H.Whittaker proposed five kingdom classification.
The kingdoms are: Monera, Protista, Fungi, Plantae & Animalia.

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5
Q

What are the main criteria used for five kingdom classification?

A

The criteria:
1. Cell structure: Presence / Absence of cell wall, Prokaryotic/ eukaryotic
2. Body org.: Cell / tissue / organ / organ system & unicellular/ multicellular
3. Reproduction: Asexual/ Sexual
4. Mode of nutrition: Autotropic / Parasitic / Saprophytic
5. Evolutionary relationships: Ancestral History

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6
Q

What is three-domain system?

A

Three domain system has been proposed dividing Kingdom Monera into two domains and leaving other kingdoms in the third domain and thereby a six kingdom classification.

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7
Q

What are the merits of five kingdom classification?

A

Merits are:
1. Bacteria, blue green algae, fungi, mosses, ferns, gymnosperms & angiosperms under kingdom Plantae: due to presence of cell wall
2. Brought together prokaryotic bacteria and blue green algae (cyanobacteria) with other eukaryotic groups.
3. Grouped unicellular & multicellular organisms: Chlamydomonas & Spirogyra were placed under algae.
4. Did not differentiate b/w heterotrophic group - fungi and autotrophic green plants (fungi had chitin cell walls while green plants : cellulosic cell walls)
5. Thus, fungi placed in separate kingdom.
6. All prokaryotic org. were grouped under kingdom Monera and unicellular eukaryotic org. in kingdom Protista.
7. Chlamydomonas along with chlorella ( earlier placed in algae within plants and both have cell walls) with Paramoecium and Amoeba ( lack cell wall and earlier placed in animal kingdom) were brought together.

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8
Q

What are the characteristic features of Kingdom Monera? How are they grouped?

A
  1. Bacteria ; sole members
  2. Most abundant
  3. Live in extreme regions: hot springs, deserts, snow and deep oceans
  4. Most are parasitic
  5. Show most extensive metabolic diversity.
  6. They are grouped on the basis of shape:
    a. Rod-like: basillus; Lactobacillus
    b. Spherical: coccus; Streptococcus
    c. Coma shaped: vibrio; Vibrio Cholerae
    d. Spiral; spirillium; Spirochetae
  7. Majority are heterotrophic.
  8. Reproduce mainly by fission.
  9. Under unfavourable conditions, they produce spores.
    a. Formation of cyst
    b. Metabolic activities slow down
    c. Under favourable conditions, cyst breaks and duaghter
    cells come out
  10. Reproduce by sort of sexual reproduction by adopting a primitive type of DNA transfer from one bac. to another. (formation of clamp)
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9
Q

What are the two different categories of Kingdom Monera? Describe their features.

A

The two categories are:
1. Archaebac.: Primitive bac.
a. Live in harsh habitats
b. Motile flagella, rigid cell wall made up of highly resistant
peptidoglycon (responsible for survival in harsh
conditions)
c. Halophiles: extreme salty areas
Thermoacidophiles: hot springs
Methanogens: Marshy areas
i. In gut of ruminants (cows, buffaloes)
ii. Responsible for production of methane (biogas)
from dung of ruminants

  1. Eubac.: True bac.
    a. Rigid cell wall and a motile flagellum (not mandatory)
    b. Photosynthetic autotrophs: Cyanobac.
    i. Blue green algae have chlor. a similar to green plants.
    ii. Unicellular, colonial, filamentousn freshwater/marine
    or terrestrial algae
    iii. Colonies are surrounded by gelatinous sheath called
    mucilagenous sheath.
    iv. Often form blooms in polluted water bodies.
    v. Some fix atmospheric nitrogen in specialised cells:
    heterocysts in nostoc (filamentous blue-green algae) ,
    anabaena
    c. Chemosynthetic:
    i. Oxidise various inorg. substances: nitrates, nitrites,
    ammonia
    ii. use released energy for ATP production
    iii. Play a imp. role in recycling nutrients like nitrogen,
    phosphorous, iron & sulphur
    d. Heterotrophic:
    i. Most abundant
    ii. Functions:
    ii.i. Imp. decomposers (majority)
    ii.ii. Making curd from milk
    ii.iii. Production of antibiotics
    ii.iv. Fixing nitrogen in leguminous roots
    ii.v. Pathogens causing damage (Cholera, typhoid,
    tetanus, citrus canker)
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10
Q

What are the characteristics of mycoplasma?

A
  1. Completely lack cell wall
  2. Smallest living cells known
  3. Cant survive with oxygen
  4. Many are pathogenic in animals and plants.
  5. eg: PPLO - Pluera Pneumonia like org.
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11
Q

What are the main features of Kingdom Protista?

A
  1. Unicellular eukaryotes
  2. Forms a link b/w plants, animals and fungi.
  3. Primarily aquatic
  4. Well defined nucleus, membrane bound organelles
  5. No specific mode of nutrition.
  6. Reproduce asexually or sexually: cell fusion / zygote formation.
  7. Cellulosic cell wall if present.
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12
Q

What are the characteristics of Chrysophytes?

A
  1. Includes diatoms, golden algae (desmids)
  2. Found in fresh / marine environ.
  3. Microscopic and float passively in water currents (plankton)
  4. Mostly photosynthetic
  5. In diatoms: cell walls form two thin overlapping shells which fit together as soap box.
  6. Walls are embedded with silica, and thus indestructible.
  7. Diatoms have left large amounts of cell wall deposits in their habitat: diatomaceous earth (granular)
  8. This soil is being gritty and hence used in polishing, filtration of oils and syrups.
  9. Diatoms: “ chief producers” in oceans
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13
Q

What are the imp. characteristics of Dinoflagellates?

A
  1. Mostly marine and photosynthetic
  2. Many pigments present in their cells
  3. Cell wall made up of stiff cellulose plated on outer surface.
  4. Bi-flagellated: one longitudinally and other transversely in a furrow b/w wall plates
  5. Red dinoflagellates (Gonyaulax) undergo such rapid multiplication that they make the sea appear red - red tides.
  6. Toxins are released in large nos. that they might kill other marine animals.
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14
Q

Describe the unique features of euglenoids.

A
  1. Fresh water org. found in stagnant water.
  2. Instead of cell wall, they have protein rich layer called pellicle which adds flexibility to their body.
  3. Bi-flagellated: long and short one
  4. Photosynthetic in presence of light and predate over small org. in the absence of sunlight (heterotrophic)
  5. Pigments are identical to those of higher animals.
  6. Biologist puzzle
  7. eg: Euglena
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15
Q

What are the unique features of Slime Moulds?

A
  1. Saprophytic protists
  2. Body moves along decaying twigs and leaves engulfing org. material
  3. Under suitable conditions, they form an aggregation called plasmodium which may grow and spread.
  4. During unfavorable conditions: plasmodium differentiated and forms fruiting bodies bearing spores at tips.
  5. Spores possess true walls and are extremely resistant and survive for many years even under adverse conditions. They are dispersed by air currents.
  6. Resembles fungi
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16
Q

Describe the features of protozoans.

A
  1. Heterotrophs: predators or parasites
  2. Primitive relatives of animals.
  3. Four major groups:
    a. Amoeboid:
    i. Fresh water, sea water, moist soil.
    ii. Locomotion and capture food by pseudopodia - false
    feet
    iii. Many have silica shells on their surface
    iv. Parasitic forms: Entamoeba
    b. Flagellated:
    i. Free living / parasitic
    ii. Have flagella (brittle)
    iii. Parasitic forms cause diseases such as sleeping
    sickness. (Trypanosoma)
    c. Ciliated:
    i. Aquatic
    ii. Actively moving org. because of the presence of cilia.
    iii. Have cavity (gullet) that opens to the outside of cell
    surface
    iv. Coordinated movement of rows of cilia causes water
    laden with food to be steered into the gullet.
    v. eg: Paramoecium: sexual dimorphism (micro and
    macro nucleus)
    d. Sporozoans:
    i. Have infectious spore-like stage in their life cycle
    ii. Most notorious plasmodium (malarial parasite) which
    causes malaria.
17
Q

What are the general features of Kingdom Fungi?

A
  1. Heterotrophic, cell wall: chitin and polysaccharides
  2. Common mushrooms and Toadstools: fungi
    White spots on mustard leaves: parasitic leaves
    Unicellular fungi, yeast: used to make bread & beer
    Wheat rust causing Puccinia, Penicillium: used to make
    antibiotics.
  3. Cosmopolitan and occur in air, water, soil and on animals and plants.
  4. Grow in warm and humid places.
  5. Filamentous
  6. Bodies consist of long, slender thread-like structures called hyphae.
  7. Network of hyphae: mycelium
  8. Two types of hyphae:
    i. Aseptate: Acellular - no partition in cells of hyphae and
    continuous.
    ii. Septate: Cellular - Partition in cells of hyphae.
    iii. Coenocytic: some hyphae are continuous tubes filled
    with multinucleated cytoplasm
  9. Symbiotic relationships:
    a. Lichens: fungi (gives water, mycobiont) + algae (gives
    nutrition, phycobiont)
    b. Mycorrhiza: (Roots of higher plant + Fungi) provides
    phosphate to plants
  10. Saprophytes: zbsorb soluble org. matter from dead
    substrates
18
Q

Explain the reproduction in fungi.

A

Vegetative means:
1. Fragmentation
2. Fusion
3. Budding

Asexual reproduction:
By spores called conidia/ sporangiospores/ zoospores
Sexual reproduction:
By oospores, ascospores, basidiospores

19
Q

What are fruiting bodies?

A

Various spores in distinct structures are called fruiting bodies.

20
Q

What are three events involved in sexual cycle of fungi?

A
  1. Fusion of protoplasms b/w two motile or non-motile gametes: plasmogamy
  2. Fusion of two nuclei: karyogamy –> leads to dikaryon stage
  3. Meiosis in zygote resulting in haploid spores
21
Q

Briefly explain the process of sexual reproduction in fungi.

A
  1. Two haploid hyphae (n): which immediately results in diploid cells (2n)
  2. In basidiomycetes and ascomycetes: 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.
  3. Later, parental nuclei fuse and cells become diploid (zygote)
  4. The fungi form fruiting bodies in which reduction division (meiosis) occurs leading to formation of haploid spores.
22
Q

What forms the basis for division of kingdom into various classes?

A
  1. Morphology of mycelium
  2. Mode of spore formation
  3. Fruiting bodies
23
Q

Describe Phycomycetes.

A
  1. Aquatic habitat
  2. On decaying wood in moist and damp places or as obligate parasites on plants.
  3. Mycelium: aseptate and coenocytic & unbranched hyphae.
  4. Asexual reproduction: takes by zoospores (motile) or by aplanospores (non-motile). These spores are endogenously produced in sporangium.
  5. Sexual reproduction: A zygospore is formed by fusion of two gametes are similar in isogamous or dissimilar (anisogamous or oogamous)
  6. eg: Mucor, Rhizopus (bread mould) & Albugo - parasitic fungi on mustard
  7. Different from others in mode of reproduction
24
Q

Describe Ascomycetes.

A

1.Sac fungi
2. Multicellular (Penicillium)
3. Unicellular (Yeast - Saccharomyces)
4. Saprophytic, decomposers, parasitic, coprophilous (growing on dung)
5. Mycelium branched, septate
6. Asexual spores: conidia produced exogenously on special mycelium called conidiophores. Conidia on germination produce mycelium.
7. Sexual spores: ascospores produced endogenously in sac like asci (singular ascus). Asci are arranged in diff. types of fruiting bodies called ascocarps.
8. eg: aspergillus, claviceps, neurospora.
9. Neurospora is used extensively in biochemical and genetic work.
10. Many members like morels and truffles are edible and are considered delicacies.

25
Q

What are Basidiomycetes? Describe their features.

A
  1. Mushrooms, bracket fungi or puffballs - also known as
  2. In plants, they grow as parasites ( rusts & smuts )
  3. Mycelium is branched and septate.
  4. Fragmentation: veg. reproduction is common.
  5. Sex organs are absent
  6. Advanced stage of fungus
  7. Plasmogamy is brought by fusion of two somatic cells of diff. strains or genotypes. Resultant structure is dikaryotic which gives rise to basidium.
  8. Karyogamy and meiosis take place in basidium producing 4 basidiospores.
  9. Basidiospores are exogenously produced on basidium.
  10. Basidia are arranged in fruiting bodies called basidiocarps.
  11. eg: Agaricus (mushroom), Ustilago (Smut) & Puccinia ( rust fungus)
26
Q

Describe Deuteromycetes.

A
  1. Imperfect fungi as only asexual / veg. phases are only known.
  2. asexual spores: conidia.
  3. Mycelium: septate & branched
  4. Some are saprophytes or parasites while many are decomposers of litter and help in mineral cycling.
  5. eg: Alternaria, Collectotrichum & Trichoderma.
27
Q

Describe the features of kingdom plantae

A
  1. Eukaryotic chlorophyll-containing org.
  2. Insectivorous plants: Venus fly trap, Bladderwort
  3. Parasite: Cuscuta
  4. Prominent chlorophylls and cell wall mainly made of cellulose.
  5. Includes algae, bryophytes, pteridopytes, gymnosperms, angiosperms.
  6. Life cycle: diploid sporophytic and haploid gametophytic and they alternate with each other. This phenomenon is called alternation of generation.
28
Q

Describe the features of Kingdom Animalia.

A
  1. Heterotrophic eukaryotic org.
  2. Multicellular and lack cell wall
  3. Digest food in internal cavity and store food reserves as glycogen or fat.
  4. Holozoic nutrition: ingestion of food.
  5. Elaborate sensory and neuromotor mech.
  6. Capable of locomotion.
  7. Sexual rep: copulation of male and female followed by embryonical development.
29
Q

What are viruses? What are there characteristics?

A
  1. Non-cellular org. that are characterised by having an inert crystalline structure structure outside the living cell.
  2. They infect a cell they take over the machinery of the host cell to replicate themselves, killing the host.
  3. Virus means venom or poisonous fluid.
  4. No virus contains both RNA and DNA. (Either RNA/DNA)
  5. A virus is nucleoprotein and the genetic material is infectious.
  6. Viruses that infect plants: single stranded RNA, viruses that infect animals have either single or double stranded RNA or double stranded DNA.
  7. Can cause diseases like: Mumps, small pox, herpes and influenza, AIDS in animals.
  8. In plants: Mosaic formation, leaf rolling or curling, yellowing and vein clearing, dwarfing and stunted growth.
30
Q

What are the discoveries regarding viruses?

A
  1. Dmitri Ivanowsky recognised certain microbes as casual org. of mosaic disease tobacco. They were found to be smaller than bac. because they passed through bacteria proof filters.
  2. M.W. Beijerinek demonstrated that the extract of infected plants of tobacco could cause infection in healthy plants and named it as virus and called the fluid as Contagium vivum fluidum (infectious living fluid).
    3.W.M. Stanley showed that virus could be crystalline and crystals consists largely of proteins. They are inert outside their specific host cell. Viruses are obligate parasites.
31
Q

What are the viruses that infect bacteria are called as?

A

Bacteriophages usually have double stranded DNA.

32
Q

Describe the structure of Virus.

A
  1. The protein coated capsid made of small subunits called capsomeres which protects the nucleic acid.
  2. Capsomeres are arranged in helical or polyhedral geometric forms.
33
Q

Who discovered Viroids? What does it mean? Describe its characteristics.

A
  1. T.O Diener discovered a new infectious agent that was smaller than viruses and caused potato spindle tuber disease.
  2. It was found to be free DNA.
  3. It lacked protein coat that is found in viruses and hence named viroid.
  4. RNA of viroid was of low molecular weight.
34
Q

What are prions? Write their characteristics.

A
  1. Infectious neurological diseases were found to transmitted by an agent consisting of abnormally folded protein.
  2. Agent was similar in size to viruses. It was called prion.
  3. Diseases caused: bovine spongiform encephalopathy (BSE) - mad cow disease in cattle and its analogue variant Cr-Jacob disease (CJD) in humans.
35
Q

What are lichens?

A

Lichens are symbiotic associations i.e. mutually useful associations b/w algae and fungi.

36
Q

What are the components of lichens?

A

Algal component is called as phycobiont and fungal component is called as mycobiont which are autotrophic and heterotrophic respectively.

37
Q

How do lichens work symbiotically?

A

Algae prepare food and fixes nitrogen for fungi and fungi provide shelter and protects it and absorb mineral nutrients and water for algae. Fungi also attaches the plant body / thallus to the substratum (rocks)

38
Q

What is ecological importance of lichens?

A

Lichens are very good pollution indicators. They do not grown in polluted areas.

Biology (2 decks)

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