Transcript 17 1 17 2 Classification and Cladograms

Mon., 12/3
Something to think about…READ it, write a paragraph. 
When you’re in a crowd, look around at all the different
people. Notice their clothes, faces, hair, sizes. Look at
their gestures and movements, noticing if they are
loose, stiff, or free. Just take it in, without judgment, as
if you were looking at a garden of people. Then see
them all as energy fields, the same as you. Just energy.
As you continue watching, think to yourself, Every
person here has had to live every day, decide what to
wear, face loss, success, hurt, shame, just like me.
Everyone fell down while learning to walk, everyone
probably felt anxious on their first day of school, just
like me. Each person has a story to tell. Some of the
chapters are heroic. Some of them are about loss, some
about fear, some about achievement or joy, just like my
story. When you encounter someone, remember that
you are a moment in their story. Make it a story that
doesn’t leave a scar.
• How would you ORGANIZE these items
into categories?
17. 1 KEY CONCEPT
Organisms can be classified based on
physical similarities!
Linnaeus developed the scientific naming system still
used today.
the science of naming and
classifying organisms
White oak:
Quercus alba
• A taxon is a group of organisms in a
classification system.
– 2-part scientific name
– Latin/Greek
– ALWAYS underline or italics !!!
– Includes 1 or more species
– Species in same genus = closely
related
– Genus name is ALWAYS
CAPITALIZED!!!
Tyto
Ex:
2nd part of scientific name
ALWAYS lowercase
always follows genus name,
(never written alone)
Ex:
alba
• So, What’s the big deal?!?!?!
– Some species have very similar common names.
– Some species have many common names.
•Unique to the
organism!
Ex:
•INTERNATIONAL use!
K
P
C
O
F
G
S
• 7 levels, each included in the
1 above it.
• Kingdom = general;  Species =
specific
What’s the order????
13.1
Ecologists
Study Relationships
YOUR
Classification!
•Homo sapiens
– Kingdom – Animalia
– Phylum – Chordata
– Class – Mammalia
– Order – Primate
– Family – Hominidae
– Genus – Homo
– Species – sapiens
The Linnaean classification system has limitations!!
• Didn’t include molecular
evidence.
– Technology didn’t exist
yet
– Based only on physical
similarities.
• Physical similarities are
not always the result of
close relationships.
• RED PANDA 
• ACTUALLY: closer
to raccoon than
panda!
• Genetic
similarities more
accurately show
evolutionary
relationships!
REVIEW!
• How do you properly write a scientific
name? (use any example!)
– 1st part =
– 2nd part =
• Which two are more closely related:
– Ursus maritimus
– Ursus americanus
– Bufo americanus
Geological Time Scale Activity
PBS Videos
17.2 KEY CONCEPT
Modern classification is based on
evolutionary relationships.
Cladistics is classification based on
common ancestry!!!
1. Phylogeny: the evolutionary history for a
group of species.
4. Use evidence from:
• living species, fossil record, and
molecular data
Diagrams?
2. Phylogenetic trees
– Scientific diagram, biologists
use to classify species
& common ancestors
• Constructed by identifying
– (#3) evolutionary relationships
• Speciation = branch
• Extinction = loss of branch!
Ex. - Phylogenetic tree
Some
show
time
&
order
Hmmm…
• Which groups
are most
closely
related?
• Which groups
are least
closely
related?
• Which group
diverged first
(longest ago)
in the lineage?
Cladogram = evolutionary tree made using
cladistics.
group of species
that share a
common
ancestor.
– Each species in a clade shares some traits
with the ancestor.
BUT…
– Each species also has traits that have
changed over time
Cladistics is a common method to make
evolutionary trees.
– classification based on common
ancestry
– species placed in order that they
descended from common ancestor
group of species
that share a
common
ancestor.
•“New” trait
•Evolution: more
related = share
more traits
•Arranging diagram!
• @ Branch splits off
• Represents most
recent common
ancestor of a clade
Derived characters = traits shared in
different degrees by clade members.
– more closely
related
species share 1 Tetrapoda clade
more derived
characters
– hash marks
2 Amniota clade
3 Reptilia clade
4 Diapsida clade
5 Archosauria clade
FEATHERS &
TOOTHLESS
BEAKS.
SKULL OPENINGS IN
FRONT OF THE EYE &
IN THE JAW
OPENING IN THE SIDE OF
THE SKULL
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
FOUR LIMBS WITH DIGITS
DERIVED CHARACTER
CLADE
1 Tetrapoda clade
2 Amniota clade
3 Reptilia clade
4 Diapsida clade
5 Archosauria clade
FEATHERS AND
TOOTHLESS BEAKS.
SKULL OPENINGS IN FRONT
OF THE EYE AND IN THE JAW
p. 527—
OPENING IN THE SIDE OF THE
SKULL
Which groups are
in the amniota
clade?
Who’s more
closely related to
turtles…rabbits
or birds?
SKULL OPENINGS BEHIND THE EYE
EMBRYO PROTECTED BY AMNIOTIC FLUID
NODE
FOUR LIMBS WITH DIGITS
DERIVED CHARACTER
So, Scientists use a VARIETY of
evidence, right?!?!?!
• Molecular data
– may confirm classification based on physical
similarities.
– Or…lead scientists to propose a NEW classification!
• DNA is usually given the last word by scientists.
Let’s Practice this so it
makes sense!
1. Critter Cladogram Activity
– BY YOURSELF!
2. Another one with REAL data!
Page 529
– BY YOURSELF!