Biological Classification – Lecture Flashcards

Question-and-Answer flashcards covering the major concepts, definitions, and examples from the lecture on Biological Classification (Chapter 2).

What three categories did Aristotle use to classify plants?

Trees, shrubs, and herbs.

Into which two groups did Aristotle divide animals?

Animals with red blood and animals without red blood.

Which two kingdoms were recognised in Linnaeus’ classification system?

Kingdom Plantae and Kingdom Animalia.

Give two major limitations of the two-kingdom system of Linnaeus.

It failed to separate (1) prokaryotes from eukaryotes and (2) photosynthetic from non-photosynthetic organisms; many forms did not fit either kingdom.

Who proposed the five-kingdom classification and in which year?

R.H. Whittaker in 1969.

List Whittaker’s five kingdoms.

Monera, Protista, Fungi, Plantae, and Animalia.

Name four key criteria Whittaker used for classifying organisms.

Cell structure, body organisation, mode of nutrition, and reproduction/phylogenetic relationships.

What more recent system divides Monera into two separate domains?

The three-domain system, giving six kingdoms in total.

Which cell-wall component distinguishes fungi from green plants?

Fungal walls contain chitin; green-plant walls contain cellulose.

Which kingdom contains all prokaryotic organisms?

Kingdom Monera.

Name the four basic shapes of bacteria.

Coccus (spherical), Bacillus (rod-shaped), Vibrio (comma-shaped), and Spirillum (spiral).

How do chemosynthetic autotrophic bacteria obtain energy?

By oxidising inorganic substances such as nitrates, nitrites, or ammonia to produce ATP.

Which bacteria thrive in extreme habitats like hot springs and salty lakes?

Archaebacteria.

Which archaebacteria live in ruminant guts and generate methane?

Methanogens.

What photosynthetic pigment in cyanobacteria is identical to that in higher plants?

Chlorophyll a.

What specialised cells in some cyanobacteria (e.g., Nostoc) fix atmospheric nitrogen?

Heterocysts.

Which wall-less bacteria are the smallest known living cells and can survive without oxygen?

Mycoplasma.

What single attribute unites all members of Kingdom Protista?

They are single-celled eukaryotes.

Which protist group includes diatoms and golden algae?

Chrysophytes.

What embeds the overlapping shells of diatom cell walls, making them virtually indestructible?

Silica.

What is ‘diatomaceous earth’ and give one industrial use.

Accumulated silica walls of dead diatoms; used for polishing or filtration of oils and syrups.

Rapid multiplication of red dinoflagellates such as Gonyaulax produces what phenomenon?

Red tides.

What flexible, protein-rich layer replaces a true cell wall in euglenoids?

The pellicle.

How do euglenoids obtain food when sunlight is unavailable?

They become heterotrophic and prey on smaller organisms.

What multinucleate, creeping mass is formed by slime moulds under suitable conditions?

Plasmodium.

Name the four major groups of protozoans.

Amoeboid, Flagellated, Ciliated, and Sporozoans.

Which flagellated protozoan causes African sleeping sickness?

Trypanosoma.

Which sporozoan parasite causes malaria?

Plasmodium.

What term describes the network of fungal hyphae?

Mycelium.

List the three sequential steps in the fungal sexual cycle.

Plasmogamy, karyogamy, and meiosis.

Which fungal class is commonly called the sac fungi?

Ascomycetes.

Give one edible member of Ascomycetes considered a delicacy.

Morels or truffles.

Which fungal class includes mushrooms and produces basidiospores externally on basidia?

Basidiomycetes.

Why are deuteromycetes referred to as ‘imperfect fungi’?

Because only their asexual or vegetative stages are known; sexual stages are absent or unknown.

What is alternation of generations in plants?

The alternation between diploid sporophytic and haploid gametophytic phases during the life cycle.

In animals, food reserves are stored mainly as _ or _.

Glycogen or fat.

Outside a host cell, what physical form do viruses exhibit?

An inert crystalline structure.

Who coined the term ‘virus’ for the infectious fluid causing tobacco mosaic disease?

M.W. Beijerinck in 1898.

Most plant viruses contain which type of nucleic acid?

Single-stranded RNA.

What protein structure encloses the nucleic acid of a virus?

A capsid composed of capsomeres.

Of what are viroids composed, and who discovered them?

Free, low-molecular-weight RNA without a protein coat; discovered by T.O. Diener in 1971.

What infectious agents consist solely of abnormally folded proteins and cause diseases like BSE?

Prions.

What two partners form a lichen, and what are they individually called?

A fungus (mycobiont) and an alga (phycobiont).

Why are lichens considered good indicators of air pollution?

They do not grow in polluted environments, so their presence indicates clean air.