BIOL1130 Lecture Notes - Lecture 3: Cuticle, Paraphyly, Saprotrophic Nutrition
7 Jun 2018
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Biodiversity
• All the different forms of life on earth
• Species; appearance, kind, all the individuals of a single form.
• Biologists have named 1.8million species
• Australian hosts about 7-8% of the worlds biodiversity
• 1.8 million named species
• 10 million living species
• I billion species ever
What is a species?
• Basic unit of taxonomy
• Different concepts of how the species taxon is defined
o Morphological species concept
▪ Based on phenotypic difference between species
o Biological species concept
▪ Based on reproductive isolation between species
▪ Defined as a group of individuals who have the potential to
interbreed with one another in nature to produce viable,
fertile offspring.
Endemism
• Endemic: a species unique to a specific geographic region assumed to
have evolved there.
• Classify: group species according to similarities.
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Systema Naturae
• Founded by Carl Linnaeus (1707-1778) – Swedish physician and botanist
• Published 10 editions of Systema Naturae between 1735 and 1758
• Consolidated a convention for naming species
• Organisms grouped into two kingdoms: plants and animals
• Used a nested hierarchy, based on shared physical characteristics
Taxonomic Hierarchy
1. Domain
2. Kingdom
3. Phylum
4. Class
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5. Order
6. Family
7. Genus
8. Species
Principles of Classification
• Taxonomy: branch of biology concerned with naming and grouping
organisms
• Every life form should have a unique name that all scientists recognize
• Binomial naming system – Genus species
• Binomials are italicized, genus is capitalized, species is not.
Biological Nomenclature
• All taxa except species have a single-word name
o E.g. Chordata (phylum), Mammalia (class), Felidae (family)
• Usually more than one species in a genus
• Specific name (epithet) can be used in any genera, e.g.
o Litoria nasuta (rocket frog)
o Perameles nasuta (long-nosed bandicoot)
o Acropora nasuta (staghorn coral)
Other eccentricities
• Species are meaningful – other rankings are subjective
• Different taxa can have the same names (e.g. Drosophila is both a species
of fruit fly and a fungus)
• Families are named after on of the genera in the clade (branch)
o Animal families: end with suffix idae
o Plant families: end with suffix aceae
Monophyletic, paraphyletic and polyphyletic taxons
• Hierarchical classification reflects phylogeny
• Each named group should be monophyletic
o Containing all descendants of a common ancestor
o Non-monophyletic groups: paraphyletic, polyphyletic
• Traditional classifications often include non-monophyletic groups
o Changing as we uncover more data about morphological and
molecular characters.
The six kingdoms of life
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Document Summary
Endemism: endemic: a species unique to a specific geographic region assumed to have evolved there, classify: group species according to similarities. Principles of classification: taxonomy: branch of biology concerned with naming and grouping, every life form should have a unique name that all scientists recognize organisms, binomial naming system genus species. Biological nomenclature: binomials are italicized, genus is capitalized, species is not, all taxa except species have a single-word name, e. g. The prokaryotes: two kingdoms: bacteria and archea, first forms of life, smallest cellular organisms, unicellular, but can form colonies, cells lack nuclei, tough cell walls. Eukaryotes: third domain of life, organisms with a membrane-bound nucleus, often have membrane bound organelles, usually multicellular, but can be uni. Kingdom animalia: appeared about 600 m. y. a, multicellular and eukaryotic, no cell walls, heterotrophs by ingestion, tissue organized in to complex organ systems, animals often have bilateral symmetry. Protostomes: simple to complex: developed body cavity, platyhelminthes flatworms, annelida earthworms, leeches, mollusca snails, octopus.
