Classification, Species Concepts, and Domains

Vocabulary flashcards generated from lecture notes covering taxonomic hierarchy, species definitions, the three domains, the four eukaryotic kingdoms, viruses, and biological nomenclature.

Biological species

A group of organisms that appear similar and can breed together to produce fertile offspring, having similar morphology and physiology with no successful exchange of genes between different species.

Ecological species

A group of organisms that all live in the same habitat at the same time.

Morphological species

A group of organisms that share many physical features that distinguish them from other species.

Population

All of the organisms of the same species present in the same place and at the same time that can inbreed with one another.

Taxonomy

The study and practice of classification, which involves placing organisms in a series of taxonomic units.

Domain

The highest taxonomic rank in the hierarchical classification system.

Archaea (Archae)

A domain of prokaryotic single-celled organisms, many of which inhabit extreme environments, featuring unique membrane lipids, cell walls not made of peptidoglycan, and $70\text{s}$ ribosomes with small subunits similar to eukaryotic ribosomes.

Bacteria

A domain of prokaryotic single-celled organisms with peptidoglycan cell walls, circular DNA, $70\text{s}$ ribosomes, and no nucleus or membrane-bound organelles.

Eukarya

A domain of organisms containing cells with a nucleus, membrane-bound organelles, linear chromosomes with histone proteins, and $80\text{s}$ ribosomes in the cytosol.

Plasmids

Smaller circular molecules of DNA found in prokaryotic cells such as Bacteria and Archaea.

Kingdom Protoctista

A kingdom of eukaryotic organisms that are single-celled or made up of groups of similar cells, including protozoans and algae, representing any eukaryote that is not a fungus, plant, or animal.

Kingdom Fungi

A kingdom of eukaryotic heterotrophic organisms that do not photosynthesise, obtain carbon and energy from dead matter or living parasites, and have cell walls containing chitin without cellulose.

Kingdom Plantae

A kingdom of multicellular eukaryotic organisms with cells differentiated to form tissues and organs, possessing cell walls containing cellulose, large permanent vacuoles, and chloroplasts for autotrophic nutrition.

Kingdom Animalia

A kingdom of multicellular heterotrophic eukaryotic organisms with differentiated cells, tissues, and organs, lacking cell walls, and possessing a unique nervous system for communication.

Hyphae

Long threads that form the body form of a fungus, which grow from a single spore and can form a mycelium.

Mycelium

The body of a fungus formed from a network of long threads called hyphae.

Fruiting bodies

Large compacted masses of hyphae produced by fungi, such as mushrooms, to release spores.

Viruses

Acellular entities visible only with an electron microscope that have no metabolism when free in the environment and rely on host cell machinery and host respiration energy to replicate nucleic acids and make viral proteins.

Nomenclature

The study of naming organisms.