Recognition, Identification and Names

Spring 2013

• Recognition relies upon previous experience with the organism. You “know” it is this, because you’ve seen it before, and have learned the name from some authority.

• The process of identification relies upon an analytical review of the characters observed, and following a logical order of inclusion and exclusion, to finally arrive at the name through the use of identification keys, for example, or some other resource.

• Confirmation of the name is done through comparison with a known “standard” (e.g., checking the specimen against previously identified specimens in a reference collection, the herbarium), or consulting with an authority who has much experience with the plant group, or checking a published treatment of the plant diversity of your region (flora) or a photographic atlas or web resource for that group of plants.

Recognition versus Identification

Elements of UnderstandingBiological Diversity

Description of Diversity

Classification of Diversity

Naming of Diversity

Identification of Diversity

Elements of UnderstandingBiological Diversity

Description: requires observation and measurement of characters and their states and synthesis of this information

Classification: requires hierarchical organization of taxa based on evolutionary relationships

Naming: requires following nomenclatural conventions and enables communication

Identification: requires tools such as keys that are based on previous description, classification, and naming of taxa

Description• Provides some basic identifiable set of

characteristics to associate with the organism.

• Can be as general or as detailed as practicality dictates.

• Needs to contain enough data to provide adequate discrimination between similar organisms.

• Needs terminology.• Descriptions are linked with a name when

there is consistency in the set of observed characters for a given organism.

Fig. 16.2

Description of Bambusa fromthe Flora of China

Classification• Classification provides ORDER to the group of entities.

• Relies on observations, many definable and comparable characters, and an ability to discern them.

• Completely effective classifications can be artificial, that is, not necessarily reflecting evolutionary relationships: i.e., trees vs. shrubs vs. herbs.

• But modern classifications are based on evolutionary history (phylogeny) because this provides predictive power.

• Biological classifications are hierarchical.

Hierarchical (nested) categories and phylogeny

PHYLUM

CLASS

ORDER

FAMILYGENUS

TIME

…have only RELATIVE meaning, not absolute meaning! …are artificially created to accommodate different hierarchical levels of organization.

…rely on inclusiveness of various shared characteristics that all members of the group should possess.

…are subject to modification as data accrue!

Taxonomic Ranks…

Naming and Nomenclature • We need names to communicate about plants with

others.• Organized system of names enables fitting the plant

into an accepted scheme.• Following formal naming rules is nomenclature (International Code of Botanical Nomenclature; ICBN)• The system must allow for changes as new

information (and other species) are discovered.• Will discuss the rules of nomenclature in more

detail later in the semester.

Names of taxonomic ranks: standardized endings*

Kingdom Chlorobionta (Viridiplantae) Phylum/Division: Magnoliophyta

(Angiospermae) Class: Liliopsida Order: Poales Family: Poaceae

Subfamily: Bambusoideae

*These are for plants and fungi; there are different ones for animals.

Names of taxonomic ranks: standardized endings*

Kingdom Chlorobionta (Viridiplantae) Phylum/Division: Magnoliophyta

(Angiospermae) Class: Liliopsida Order: Poales Family: Poaceae

Subfamily: Bambusoideae

*These are for plants and fungi; there are different ones for animals.

Name of a bamboo

Class: Liliopsida (Monocots) Order: Poales Family: Poaceae

Subfamily: Bambusoideae Genus: Chusquea Kunth Species: Chusquea pohlii L. G. Clark

Genus names

• Do not have standardized endings• Must be italicized• Often the name of the author follows

the genus name

Chusquea Kunth

Species names

• Are always a binomial (genus name or epithet + species name or epithet)

• Must be italicized• Often appear with the name of the

author(s) of the species

Chusquea pohlii L. G. Clark

Classification and Names

• Ideally, classification should reflect phylogeny

• And names should reflect the classification and phylogeny

Identification

• Relies on previous description, classification, and naming of taxa

• Keys are the primary means of plant identification

• Keys can take different forms, but the most common is still the dichotomous key

Dichotomous keys

• Consists of a series of two contrasting statements (each called a lead); each pair of statements is called a couplet

• Should be able to eliminate one set of possible identifications at each couplet

• Rules for constructing dichotomous keys are found on pp. 29-31 of the lab manual

Fig. 15.1

http://www.eeob.iastate.edu/research/bamboo/keys.html

Interactive keys