Binomial Nomenclature And
The Future of Classification
Know how the Linnaeus system should be used.
Describe how biochemistry can be used in
classification.
Compare and Contrast the five kingdom and
three-domain classification systems.
Binomial Nomenclature
• Use the first name from the Genus. This
must have a capital first letter!
• Use the Species name as the second
name. This must have a lower case first
letter!
• Both words should be written in italics
Why Change?
• Original classification was based entirely
on physiology that can be observed.
• By the seventeenth century microscopes
had been developed to allow us to look at
differences between single celled
organisms, fungi and plants etc.
• Now electron microscopes help highlight
specific differences that could not be
observed earlier.
Aristotle’s Method
• All living things are either plants or
animals.
• Animals can be divided into three groups:
• Live and move in water.
• Live and move on land.
• Move through the air.
• What problems might this cause?
• Where does man fit into this?
The Five Kingdom classification
system
• Prokaryotes
•
•
•
•
•
•
No nucleus
Loop of naked DNA
No membrane bound organelles
Smaller ribosomes than other groups.
Respiration occurs in cytoplasm.
Small cells
The Five Kingdom classification
system
• Protoctists
•
•
•
•
•
Eukaryotes
Mainly single celled (some multicellular)
Large variety of types
Plant or animal like features
Autotrophic or heterotrophic
The Five Kingdom classification
system
• Fungi
• Eukaryotes
• Chitin based walls surround cytoplasm
• Network of strands form body (mycelium) strands
are called Hyphae.
• Multinucleate cytoplasm
• saprophytic
The Five Kingdom classification
system
• Plants
•
•
•
•
•
Eukaryotes
Multicellular
Cellulose cell wall surrounds the cell
Produce multicellular embryos from fertilised egg!
Autotrophic
The Five Kingdom classification
system
• Animalia
•
•
•
•
Eukaryotes
Multicellular
Heterotrophic
Fertilised eggs develop into a ball of cells called a
blastula.
• Often free moving.
Biochemistry
• Simple differences in the enzymes and
biomolecules used by different organisms can
show us how species have been related in the
past.
• Cytochrome C is used in the respiration process.
Nearly all organisms must respire, but many
have different forms of Cyt-C.
• By looking at the amino acid structure we can
identify how similar the Cyt-C is in between
species. The more similar the Cyt-C, the more
closely they are related!
Three Domain System
• Carl Woese based ideas on RNA studies
in 1990 to develop a biochemical method
of classification.
• He divided the prokaryote kingdom in two
(Eubacteria and Archaebacteria).
• He had another domain called Eukaryote.
• This system also made use of structural
differences, but relied on bichemistry as
well.
What do Eubacteria have that
Archaebacteria Do Not?
• Different cell membrane structure.
• Flagella with different internal structures.
• Different enzymes (RNA polymerase) for
building RNA
• No protein bound to their genetic material.
• Different mechanism for DNA replication
and building RNA.
Archaebacteria Have Similarities
With Eukaryotae!
• Similar enzymes (RNA polymerase) for
building RNA.
• Similar mechanisms for DNA replication
and building RNA.
• Productions of some proteins that bind to
their DNA.
Questions
• What is the main difference between the
two classification systems?
• Will this have an effect on the Linnaeus
method of naming new organisms?
• Which is the most specific way to group
and classify species?
• Which do you think should be used and
why?