Transcript Phylogenetic Tree (Cladogram) Notes

Because of
evolution there is
great diversity of
life!
Scientists need to
organize over 2 million
organisms!
Classification
Classification: grouping
organisms based on common
ancestors and characteristics.
What are some common
characteristics you can think of?
Development of
Classification
At first…
Classified organisms as
either plants (plantae) or
animals (animalia)
Is every living thing a plant or
animal?
Carolus Linneas
Hierarchical system =
classifies in levels
**On the EOC you may see
this attributed to
Aristotle**
Kingdom < most general
Phylum
Class
Order
Family
Genus
Species < most specific
Carolus Linneas
Binomial nomenclature = naming
organism types with two names
Genus: Second smallest level
Species: Smallest level
Homo sapiens
Genus species
Systems of Classification
What organism do you think this is based on the
binomial (species name)?
Canis familiaris
dog
What organism do you think this
is based on the binomial
(species name)?
Felis domesticus
cat
What organism do you think
this is based on the binomial
(species name)?
Homo sapiens
Humans!
Modern Classification
Uses evolution!
Scientists use the following criteria
to classify organisms:
Structural similarities: similar
fossils
Biochemical analysis: DNA,
proteins and amino acids
Embryology: similar embryos
Think:
What is classification?
What were the 2 kingdoms at
first?
What is the most GENERAL
level?
What is the most SPECIFIC
level?
Phylogenetic trees
Phylogenic trees show what traits species
have
You can use them to:
1. Find which organisms are most
primitive.
2. Find which organisms are most
closely related
Primitive:
Primitive = old, simple
The most primitive species are at the
bottom (left)
The most recent species are at the top
(right)
Most primitive
Most recent
Closely related:
Organisms have the traits that come
before them
ex. Perch has jaws
Species are closely related if they branch
off close together
Think:
In the cladogram, what
species is most primitive?
In the cladogram, what
species is least primitive?
What traits does the lizard
have?
What traits does the
salamander have?
What is the chimp most
closely related to?
Is the lizard more closely
related to the salamander or
the perch?