What is biological classification?
Scientific approach to grouping organisms based on current understanding of - the cell, organisation in living systems, molecular basis of heredity and behaviour of micro-organisms
Define the modern hierarchal classification
8 taxonomic categories
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Define the traditional five kingdom system
- Monera - single cell prokaryotes, absorb/photosynthesize food => (split into TWO KINGDOMS - 1.BACTERIA –> 2. ARCHAEBACTERIA,
The division of Monera into Bacteria and Archaea is based on differences in ribosomal RNA genes) - Protista - single cell eukaryotes, absorb ingest/photosynthesize food
- Plantae - multi-cellular eukaryotic organisms, photosynthesise food
- Fungi - multi-cellular eukaryotic organisms, absorb food
- Animalia - multi -cellular eukaryotic organisms, able to move/ingest food
How is the traditional five kingdom system classified?
By phylogenetic relation
Define the traditional six kingdom system
- Bacteria
- Archaea
- Protista
- Plantae
- Fungi
- Animalia
How is the traditional six kingdom system classified?
From RNA
Define the three domain system
- Bacteria
- Archaea
- Eukarya
How is the three domain system classified?
Based on phylogenetic relationship
What are some difficult cases to classify?
- Fungi = classed as fungi but are unicellular
- Viruses = not considered ‘alive’ => contains RNA /DNA but don’t grow on their own
- Prions = denatured proteins which can cause other proteins to do the same
Define engineering classifications
In the way they function, environmental requirements (pH, temp etc.)
What are the four functional aspects of engineering classifications?
· 4 functional aspects
- Free oxygen requirements
- Carbon source
- Energy source
- Temperature preference
Describe the free oxygen requirements
· Free oxygen requirements
- Obligate aerobic organisms require free oxygen for aerobic cellular respiration
- Obligate anaerobic organisms are inhibited by oxygen presence => obtain energy through respiration by alternate sources e.g. sulphate, nitrate
- Facultative aerobes/anaerobes have preference but can operate in opposite mode
- Aerotolerant anaerobes can tolerate oxygen presence but cant use it for growth
Describe the energy sources
· Energy source
- Phototrophy - light –> chemical energy
- Chemotrophy - energy obtained by oxidising chemical compounds
Describe the carbon sources
- Autotrophy - CO2 and H2O used to produce organic compounds
- Heterotrophy - complex organic compounds used for biosynthesis
Describe the temperature preferences
· Temperature preference
- Mesophiles - grow best in range 25-40
- Psychrophiles - grow well at temps near 0
- Thermophiles - prefer higher temps i.e.»_space;55
