Download Classification - Groby Bio Page

Starter: Group the TV Shows
Sponge Bob
Squarepants
Star Trek
ER
Friends
Heroes
Neighbours
Big Brother
X factor
Doctor Who
House
Lost
The Simpsons
Eastenders
Futurama
Desperate
Housewives
Learning objective
 To understand how and why we classify organisms
Success criteria
 Define the terms classification, phylogeny and taxonomy
 Discuss the changes to classification systems over time
 Describe the classification of species into the taxonomic
hierarchy of domain, kingdom, phylum, class, order, family,
genus and species
 Compare and contrast the five kingdom and three domain
classification systems
 Explain the relationship between classification and
phylogeny
Key Terms
 Taxonomy
 The study of the principles behind classification
 Classification
 The process of organising of living organisms into
groups.
 Natural classification – grouping according to how
closely organisms are related and reflects evolutionary
relationships
 Phylogeny
 The study of evolutionary relationships between
organisms
Classification and Phylogeny
 Classification of organisms depends their evolutionary
relationships
 Phylogeny is the study of the evolutionary
relationships between organisms
Phylogeny Questions


1.
2.
3.
Turn to page 200 and look at Fig 1
Which two are closer related?
Gorilla, Thrush, Snake
Man, Gorilla, Snake
Snake, Frog, Trout
Phylogeny Answers
Gorilla, Thrush, Snake
1.
1.
Thrush and Snake, share a more recent common
ancestor
Man, Gorilla, Snake
2.
1.
Man and Gorilla, share a more recent common
ancestor
Snake, Frog, Trout
3.
1.
All same relation, have the same common ancestor
(this is known as monophyletic: all evolved from
same species)
Taxonomic Hierarchy: Domain
Evolution of classification systems
 Carl Linnaeus started it all off 250 years ago using visible
features of organisms - limited
 C17th microscopes allowed us to look at cells, later electron
microscopes allowed us to look inside cells
 Physiology
 How living organisms work
 Biochemistry
 Comparison of biological molecules eg. Cytochrome c
(protein used in respiration: almost all species have it, but it is
not identical in all, the more similar the amino acid sequence
the more closely related the organisms)
 DNA
 Comparison of DNA sequences – probably most accurate
Classification systems (from GCSE)
Organisms can only belong to one group in the taxonomic hierarchy.
As you rise through the ranks of classification (taxa) the individuals
grouped together show more and more diversity
Levels of Classification
K
 Kingdom
P
 Phylum
 Crisps
 Class
 Only
 Order
 Fry
 Family
 Good
 Genus
 Spuds
 Species
Activity
 Come up with a mneumonic to remember the taxa of
classification
D
K P
C
O
F
G
S
Taxonomic Hierarchy
Taxonomic
Hierarchy
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Humans
Eukaryote
Animalia
Vertebrate
Mammal
Primate
Hominid
Homo
sapiens
Chimpanzee
Eukaryote
Animalia
Vertebrate
Mammal
Primate
Hominid
Pan
troglodites
The 5 kingdoms
(We’ll come back to this next
lesson in more detail)
PROKARYOTES
Prokaryotes
Kingdom vs Domain
 In 1990 Carl Woese suggested 3 Domain classification
system based on fundamental differences in RNA
 He divided the prokaryotes into
 Bacteria (Eubacteria)
 Archaea (Archaebacteria)
 This is now widely accepted
Taxonomic Hierarchy: Domain
What is a species?
The hierarchy ends with species. A group that can
contain only one organism.
A species is a group of similar organisms able
to reproduce and produce fertile offspring.
Scientists constantly update the classification systems
because of discoveries about new species and new
evidence about known organisms.
Exam question June 2010 Q.2
a)
placing, living things / organisms /
named organisms, into, groups /
categories / taxa / named taxonomic
groups ;
based on / AW, similarity / difference ;
b)
1. morphology / anatomy / (observable /
physical) features / appearance / AW ;
ACCEPT ‘grouping living things’
Look for the idea of similar organisms being
placed in the same group or different
organisms being placed in different groups
2. biochemistry / cytochrome C ;
1 CREDIT cell features e.g. nucleus /
membrane- bound organelles / cell wall /
prokaryotic-eukaryotic features /
unicellular
2 CREDIT component of cell wall
3. genes / DNA / genetics / RNA ;
3 IGNORE chromosomes
4. behaviour / physiology / embryology ;
4 ACCEPT ‘how they feed’ / nutrition / ‘how
they reproduce’
5. idea of shared, evolutionary past /
phylogeny ;
5 ACCEPT ‘how closely related’
IGNORE refs to interbreeding / fertile
offspring
Exam question June 2010 Q.2
b ii)
TSRWUQ;;;
c)
1. 3 domains AND 5 kingdoms ;
2. domains are, bacteria / eubacteria, AND,
archaea / archaebacteria, AND,
eukarya / eukaryotes ;
3. kingdoms are prokaryotes AND
protoctists AND fungi AND plants
AND animals ;
4. eukaryotes split into different kingdoms
/ all eukaryotes are in the same domain ;
5. all prokaryotes are in the same kingdom
/ prokaryotes split into different
domains ;
6. domain classification based on, rRNA /
ribosomes / RNA polymerase / protein
synthesis / enzymes / flagella /
membrane structure ;
Mark the order of letters (ignoring
the dotted lines)
All 6 in correct order = 3 marks
If any incorrect, then credit
T S in order at beginning = 1 mark
U Q in order at end = 1 mark
R before W anywhere in the sequence = 1
mark
ACCEPT phonetic spellings
ACCEPT alternative terms for names of
kingdoms and domains throughout (e.g.
plants / plantae)
2 ACCEPT ‘eukaryota’
3 DO NOT CREDIT protists / protozoa
6 IGNORE RNA unqualified
DO NOT CREDIT other forms of RNA
ACCEPT any detail of protein synthesis
Plenary
 Why do we study how closely related we are to other
species?
 To help us understand our own evolution. By studying
the organisms that are closely related to us can help us
to understand our own biology and behaviour.
Homework
 Find 3 closely related organisms (same from the
Domain to the Genus taxa)
 Find 3 organisms that are not closely related (different
at the Domain taxa)
 Write out their full classification: domain to species
taxa