1.1 Taxonomy
Taxonomy
Definition
Taxonomy: The practice of classifying biodiversity; aims to classify all organisms within the biosphere, including both living and fossilized organisms.
Organisms are grouped into classifications called taxa (singular: taxon).
Importance of Classification
Reasons for Classification
Identifying and classifying organisms in the biosphere is crucial for:
Effectively using them as resources.
Protecting them from invasive species or other dangers.
Real-World Application of Classification
Example of Classification Importance: Identifying which plants are safe to eat.
Plants to Assess:
Hemlock
Foxglove
Carrot
Poison Ivy
Buttercup
Monkshood
Case Study: The Emerald Ash Borer
An invasive species from Asia that has significantly impacted ash trees in Ontario.
By identifying the pest and its prey, control measures have slowed the infestation.
Biomonitoring
Definition
Biomonitoring: A strategy to identify specific organisms’ presence or absence to assess the health of ecosystems.
Often used for monitoring water quality.
Historical Context
Carl Linnaeus
Carl Linnaeus (1707-1778):
Swedish botanist and medical doctor known as the "Father of Modern Taxonomy".
Grouped organisms based on structural similarities.
Proposed the binomial nomenclature system in 1758 for naming organisms.
Binomial Nomenclature
Overview
Binomial Nomenclature: A two-word system for uniquely naming organisms.
Binomial = two; Nomenclature = naming.
Uses the two smallest taxa: genus (plural: genera) and species.
Example of Naming
Common Name: Briar Rose
Pre-Linnaeus Names:
Rosa sylvestri inodora seu canina (odourless woodland dog rose)
Rosa sylvestris alba cum rubore folio glabro (pinkish white woodland rose with smooth leaves)
Linnaeus Binomial Nomenclature: Rosa canina
Genus: Rosa
Species: canina
Formatting Rules
Generic name (genus) is capitalized; both words are italicized.
Examples:
Lynx rufus (Bobcat)
Felis catus (Domestic Cat)
Canis lupus (Wolf)
Taxonomic Hierarchy
Structure of Taxonomy
Organisms classified beyond just genus and species; further grouped into levels based on shared characteristics.
Linnaean Classification System contributes to an understanding through 8 taxa:
Domain (broadest)
Kingdom
Phylum
Class
Order
Family
Genus
Species (most specific)
Mnemonic Device
A popular mnemonic for remembering order: "Dear King Philip Called Out For Good Soup".
Taxonomy Examples
Common Name: Brown Bear
Taxonomic Hierarchy:
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Ursidae
Genus: Ursus
Species: arctos
Example with Common Name: Killer Whale
Taxonomy:
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Family: Delphinidae
Genus: Orcinus
Species: orca
Methods of Classification
Classification Methodologies
Biological
Morphological
Phylogenetic
Biological Grouping
Organisms grouped by reproductive ability. This is commonly accepted as the definition of a species.
Species: Group of organisms that can naturally breed and produce fertile offspring.
Hybrid: An organism produced through the successful mating of two different species.
Example: Labradoodle (cross of Labrador and Poodle).
Morphological Grouping
Organisms grouped by similarities in structural and physical features (morphology) like colour, size, and shape.
Limitations to Morphological Grouping
Taxonomy based on morphology can be challenging due to:
Significant physical variance within a species.
Minor visible differences between species.
Genetic structures leading to similar physical traits.
Mutations causing incorrect classifications.
Developmental stages concealing relationships.
Phylogenetic Grouping
Phylogenetics: The study of evolutionary relationships.
Organisms grouped based on their evolutionary paths.
Limitations of Phylogenetic Grouping
There are challenges in phylogenetic grouping as evolutionary histories of all organisms may not be fully known.