Biological Classification

Vocabulary practice flashcards covering Chapter 2: Biological Classification, including systems of classification, Kingdom Monera, Kingdom Protista, Archaebacteria, Eubacteria, Cyanobacteria, and related concepts.

Aristotle's Classification System

The earliest scientific classification system, which categorized plants into trees, shrubs, and herbs based on simple morphological characters, and divided animals into two groups: those with red blood and those without.

Two Kingdom System

A classification system developed in Linnaeus' time that divided organisms into Kingdom Plantae and Kingdom Animalia, without distinguishing between eukaryotes and prokaryotes, unicellular and multicellular organisms, or photosynthetic and non-photosynthetic organisms.

Five Kingdom Classification

A classification system proposed by R.H. Whittaker in 1969 comprising Kingdom Monera, Kingdom Protista, Kingdom Fungi, Kingdom Plantae, and Kingdom Animalia.

Whittaker's Classification Criteria

The main criteria used by R.H. Whittaker for classifying organisms, which include cell structure, body organisation, mode of nutrition, reproduction, and phylogenetic relationships.

Three-Domain System

A classification system that divides Kingdom Monera into two domains and places all eukaryotic kingdoms in a third domain, resulting in a six kingdom classification.

Monera Cell Wall Composition

A noncellulosic cell wall structure composed of polysaccharides and amino acids, characteristic of Kingdom Monera.

Chitin Cell Wall

The characteristic cell wall structure found in fungi, distinguishing them from green plants which have cellulosic cell walls.

Kingdom Monera

A kingdom comprising all prokaryotic, single-celled organisms, of which bacteria are the sole members.

Coccus

A category of bacteria characterized by a spherical shape (plural: cocci).

Bacillus

A category of bacteria characterized by a rod shape (plural: bacilli).

Vibrium

A category of bacteria characterized by a comma shape (plural: vibrio).

Spirillum

A category of bacteria characterized by a spiral shape (plural: spirilla).

Bacteria Shapes

The categorization of bacteria into four groups based on shape: spherical Coccus, rod-shaped Bacillus, comma-shaped Vibrium, and spiral Spirillum.

Archaebacteria

A group of special bacteria with a unique cell wall structure enabling them to survive in harsh extreme habitats, such as extreme salty areas, hot springs, and marshy areas.

Halophiles

Archaebacteria that inhabit extreme salty areas.

Thermoacidophiles

Archaebacteria that inhabit hot springs and acidic extreme habitats.

Methanogens

Archaebacteria found in marshy areas and in the gut of ruminant animals (such as cows and buffaloes) that produce methane (biogas) from animal dung.

Eubacteria

Also known as 'true bacteria', characterized by the presence of a rigid cell wall and, if motile, a flagellum.

Cyanobacteria

Photosynthetic autotrophic eubacteria, also referred to as blue-green algae, which contain chlorophyll a similar to green plants and are often surrounded by a gelatinous sheath.

Heterocysts

Specialised cells found in certain cyanobacteria, such as Nostoc and Anabaena, that perform atmospheric nitrogen fixation.

Nostoc

A filamentous blue-green alga (cyanobacterium) that forms colonies with a mucilaginous sheath and contains specialized heterocysts for nitrogen fixation.

Chemosynthetic Autotrophic Bacteria

Bacteria that oxidise inorganic substances such as nitrates, nitrites, and ammonia to release energy for ATP production, playing a major role in recycling nitrogen, phosphorus, iron, and sulphur.

Heterotrophic Bacteria

The most abundant bacteria in nature, acting primarily as decomposers and playing key roles in curd production, antibiotic synthesis, and nitrogen fixation in legume roots.

Mycoplasma

Organisms that completely lack a cell wall, representing the smallest living cells known; they can survive without oxygen and are often pathogenic to plants and animals.

Kingdom Protista

A kingdom containing all single-celled eukaryotic organisms, primarily aquatic, which form a link with plants, animals, and fungi.

Chrysophytes

A group of aquatic, microscopic, photosynthetic protists that includes diatoms and golden algae (desmids).

Diatomaceous Earth

Large cell wall deposits formed over billions of years from silica-embedded, indestructible cell walls of diatoms, used in polishing and filtration of oils and syrups.

Dinoflagellates

Mostly marine, photosynthetic protists with stiff cellulose wall plates and two flagella, some of which multiply rapidly causing 'red tides' and releasing lethal toxins.

Euglenoids

Freshwater stagnant-water protists that lack a cell wall, possess a flexible protein-rich pellicle, have two flagella, and behave photosynthetically in sunlight or heterotrophically in darkness.

Pellicle

A protein-rich layer covering the body of euglenoids instead of a cell wall, making their body flexible.

Slime Moulds

Saprophytic protists whose body moves along decaying twigs and leaves engulfing organic material, forming plasmodium aggregates or spore-bearing fruiting bodies under unfavourable conditions.

Plasmodium (Slime Moulds)

An aggregation formed by slime moulds under suitable conditions that can grow and spread over several feet.