4/9 Daily Catalyst
Pg. 45 Classification
1. What do we expect about the ancestary from two
homologous organisms?
2. Which is most likely to become fossilized?
a. Teeth
b. flowers
c. worms
d. eggs
3. Why don’t intrusion layers contain fossils?
4/9 Class Business
Pg. 45 Classification
 Quiz #11 on Friday
 Evidence for Darwin’s Theory
 Evolution test on Thursday, April 16th
 Study guide due test day
 Review day on Wednesday, April 15th
 Quiz #12 on Review day
 Human body begins on Friday, April 17th
4/9 Agenda
Pg. 45 Classification
Daily Catalyst
Class Business
Review questions
Classification Notes
Dichotomous Key stations
4/9 Objective Pg. 45 Classification
 Today, we will be able to classify organisms
from different kingdoms at several taxonomic
levels, using a dichotomous key and compare
characteristics of the major kingdoms.
Darwin’s evidence Pg. 24
Fossils
Biogeography
Comparative
anatomy
Classification
Review questions
 Please raise your hands to answer the questions for a
treat
Groups of fossils that are similar, but found in different
INDEX
FOSSILS
places are known as ________
________.
 Birds and insects both have wings to fly the sky
ANALOGOUS
Which fossil layer is older, 3 or 3?
 Snakes don’t have legs, but they do have small hip
and leg bones. What type of structure?
VESTIGIAL
Review
 Label the diagram:
Explore activity
 Directions: Group the provided shark teeth into groups of
your choice.
 What characteristics did you use to group the shark teeth?
 How would you classify the shark teeth?
 Are there multiple categories you could put them in? If so,
what are they?
 Noise: 2 (with group)
 Time: 6 minutes
Classification
 Before Darwin:
organisms were
classified based on
physical similarities
and differences
 After Darwin:
organisms were
classified based on
how recent their
common ancestor is
and how much DNA
they have in common
Key point #1:
 Scientists classify organisms based on
characteristics.
 Key Point #1:
 Homologies: similarities in DNA between organisms
 Share an ancestor= share more DNA
 Show patterns of descent
 Place relations on a evolutionary tree
Evolutionary
Tree
 Key Point #2:
 Branches are determined by:
 Anatomical (structures) similarities
 DNA similarities
Two types of classification:
 Cladograms
 Dichotomous Keys
Key Point #3: A cladogram shows DNA
similarities between organisms
The more recent the common ancestor,
DNA
the more ________
they have in
common!
Cladograms
 Cladograms are based on Darwin’s theory of natural
selection:
 Evolution means new heritable traits develop in a
population
 These traits are passed on to generations
How to read a cladogram
Key Point #4:
Branch: the closer branches
mean closely related
organisms
Node: the last shared
ancestor/trait
Root: the common ancestor
for all organisms
Common ancestor
Class Questions
What organism is most
closely related to the
Caiman?
Melanosuchus
Class Questions
Tomistoma shares a close
common ancestor with
which two organisms?
Osteolaemus and
Crocodylus
Class Questions
Which organism is
most closely related
to primates?
Rodents and
rabbits
Class Questions
What can you
tell me about
the DNA of
the primates
and rodents?
They must
be similar
Class Business
What
characteristic do
ray-finned fish
and birds have in
common?
Bony Skeleton
Dichotomous Key Explore
 All members of the class will receive one piece of
candy.
 When you receive your piece of candy, DO NOT OPEN
IT or EAT IT.
 Please leave your candy on your desk
Dichotomous Key
 1a. You have a piece of candy… go to 2
 1b. You do not have a piece of candy… stop
Dichotomous Key
 2a. Candy has a wrapper… go to 3
 2b. Candy does not have a wrapper… go to 4
Dichotomous Key
 3a. Candy has a solid tin foil wrapper… go to 5
 3b. Candy has a stripped tin foil wrapper… go to 6
Dichotomous Key
 5a. Candy wrapper is a silver
color… go to 7
 5b. Candy wrapper is a red and
gold color… go to 8
 6a. Candy wrapper is gold
and brown stripped… go
to 7
 6b. Candy wrapper is red
and white striped
… Candy Cane
Dichotomous Key
 7a. Candy is raindrop
shop…go to 9
 7b. Candy is rectangle
shape…go to 10
 8a. Candy is square
shape…go to 9
 8b. Candy is circular in
shape…got to 10
Dichotomous Key
 9a. Candy has a white tag in the wrapper …go to step 11
 9b. Candy has sugar on the outside…gum drop
Dichotomous Key
 11a. Candy has caramel on
the inside …. Hershey
caramel Kiss!
 11b. Candy is made of
chocolate…Hershey Kiss
 12a. Candy is striped
chocolate…Hugs
 12b. Candy has caramel
and dark chocolate
inside…Milk way Night
Key Point #5:
Key Point #5: Scientist use a
dichotomous key to classify based on
physical characteristics.
 Classify based on what?!
Physical appearance!
Just like taking a quiz in a magazine!
If you like comedies go to
#3…
If you like dramas go to
#4…
To use a dichotomous key
1.Begin with step 1a.
2.Look at the organism you are classifying.
3. If step 1a is true, do what this step tells
you to do.
4.If step 1a is NOT true go to step 1b. If step
1b is true, do what it says.
5.Repeat this until you can name the
organism
Let’s practice!
1a. Tail fins are horizontal…………….. Go to 2
1b. Tail fins are vertical…………………Go to 3
Let’s go to 3!
Let’s practice!
3a. Has gill slits behind mouth……………go to 5
3b. Has no gill slits…………………………
Lepidosiren paradoxa
Let’s go to 5!
Let’s practice!
5a. Head is hammer shaped………Sphyrna
mokarran
5b. Tail fins are half the body lenth…Alopias vulpinus
Sphyrna mokarran
 Based on physical appearances that other scientists
have discovered, we can name any organisms that we
do not know!
 What is one downside of this style of classification?
 It is based purely on physical characteristics that
could be misinterpreted by people.
Work time
 Directions: As a group, complete the 3 dichotomous
key at each station. You have 7 minutes to complete
each key. When you have finished the keys, return to
your desk. The keys will be completed on a lined
sheet of paper. This paper need to be turned in Friday
for credit.
 Time: 21 minutes
 Noise: 1(with groups)
1
2
3
4
5
6
7
8
Fabien
Amani
Stephe
n
Smoke
y
Ridel
Avery
Eliud
Nicoh
Jonath
an
Hefer
Daniel
G.
David
Eric
Mickey
Daniel
V.
Barrian
Brian
Stepha
nie
Eva
Kayla
Francis
co
Zaven
Chris E. Chase
Terriya
n
Andrea Nick
Darrius
Eduard
o
Travis
Conclusion
 With a partner, answer the following question in your notes.
 Draw a cladogram depicting relationship between the
species (including humans) with the following information in
the chart.
Species
Percent DNA similarity
Chimpanzee
99.6%
Dog
91.3%
Fruit Fly
74.2%
Roundworm
50.8%
CHIMP
DOG
FRUIT
FLY
ROUND
WORM
HUMANS