Glossary of Terms
See the Glossary of Phylogenetic Systematics for a more complete listing and in depth discussion of terms
Adaptive radiation
The evolution of new species or sub-species to fill unoccupied ecological niches.
Adequacy
(in relation to a Protected Area System) The principle that the system is capable of maintaining biodiversity and associated ecological patterns and processes.
Allele
One of the alternative forms of a gene. Most genes in natural populations occur in more than one form.
Biogeography
The study of the geographic distributions of species and the historical explanation of these patterns.
Biota
The plant and animal life of a particular region or period.
Character
A heritable feature (e.g. tooth shape or DNA sequence) of a group of organisms that exists in multiple forms.
Cladistics
The practice of classifying organisms based on their phylogenetic relationships and evolutionary history. Its goal is to delineate 'natural' groups which reflect 'true' relationships.
Clade
A monophyletic group containing an ancestral taxon and all of its descendants.
Chromosomes
Structures in the cell nucleus, each containing the DNA for many hundred genes, packaged with proteins.
Comprehensiveness
(in relation to a Protected Area System) The principle that the system encompasses the full range of biological/biophysical diversity.
Conspecific
Belonging to the same species.
Dispersal
The spread of animals, plants or seeds to new areas.
Endemism
Presence within a localised area; peculiar to that area.
Extant
Still in existence, surviving. Antonym: extinct.
Genus
(pl. Genera) A taxonomic group containing one or more closely-related species
Genome
The complete collection of the genetic material of an organism.
Gondwanaland
The supercontinent formed by the union of Australia, South America, Africa, India and Antarctica during the late Palaeozoic and Mesozoic eras (up to 120 million years ago).
Haplotype
The combination of alleles of different genes that are present in an individual.
Hybridization
The interbreeding of animals or plants of different species.
Intergeneric
Between genera
Maximum parsimony trees
The phylogeny of a group of species can be represented by a branching diagram called a tree. If the changes in characters between species required by a particular tree is counted, the tree which requires the least number of changes is said to have the maximum parsimony.
Mesozoic Era
The era between about 225 and 65 million years ago, comprising the Triassic, Jurassic and Cretaceous periods.
Mid-Cretaceous
About 110 to 80 million years ago - the middle of the Cretaceous period (145 to 65 million years ago).
Mitochondria
Small organelles in the cell where energy from electron transport between molecules is converted into energy for biological activity. Mitochondria also possess their own genome, which is inherited maternally.
Monophyletic
A clade that comprises an ancestral taxon and all of its descendants, and no other taxa.
Morphology
The study of the form of animals - usually external and often contrasted with anatomy, the study of the internal form.
Niche
The range of environmental variables such as temperature, humidity, etc. in which a species can survive and reproduce.
Nuclear genome
The portion of the genome contained in the nucleus ie the chromosomes.
Paraphyletic
A group of taxa that includes an ancestral taxon but not all descendants of that taxon - e.g. "fish" is a paraphyletic group because it does not include the other vertebrates, which undoubtedly also derive from the ancestral fish species.
Phylum
A large group of supposedly monophyletic species - such as the Arthropods (spiders, insects, crustaceans and millipedes)
Phylogeny
The genealogical history and evolutionary development of a species or higher taxon.
Polymorphism
The occurrence of more than one form of, for example, a DNA sequence, type of protein or morphological trait in a group of organisms, revealing underlying genetic variation in the population.
Pseudogene
A gene copy created by a gene duplication event that is no longer functional due to a disabling mutation.
Ranking metrics
(in relation to a Protected Area System) Statistics that rank various geographic areas in terms of their priority for inclusion in conservation reserves. Using genetic data forexample, the metrics may include the number of alleles seen only at one site, the amount of genetic variation at the site and the degree of genetic differentiation.
Representativeness
(in relation to a Protected Area System) The principle that the system samples known biological and biophysical diversity and other values.
Restriction Fragment Length Polymorphisms
Restriction enzymes cut DNA wherever their "recognition site" (usually between 4 and 8 bases in length) occurs in the DNA sequence. When there are changes between sequences, a recognition site may appear or be lost. This can be detected by electrophoresis, and is called a polymorphism.
Ribosomal DNA genes
The genes that make the three RNA components of the ribosome - the particle (also containing 60 or more proteins) that is responsible for making proteins within the cell.
Species
A classification of related organisms that can freely interbreed.
Speciation
The processes by which a single species splits into two or more species
Sympatric
Occurring in the same place.
Synapomorphy
Shared derived characters that are regarded as homologous are called synapomorphies, e.g. the presence of mammary glands in all three lineages of mammals (monotremes, marsupials and placentals). These sorts of characters suggest a close relationship of the organisms that share them.
Taxon
(pl. taxa) A group of animals classified as a named set, supposedly of the same type.
Tectonics
The process by which the earth's surface has attained its present structure.
Copyright © 2003, Australian Museum
