Changing Times Changing Organisms Activity Sheet (Honors)
Name_____________________________
Change in Atmospheric Oxygen in Earth Overtime
Date______________ Per._____
Inquiry Activity #1: Timeline of life.
Instructions:
The fossil record and radiometric dating reveal that the oldest rock fossil was formed 4.6
billion years ago (b.y.a.) (4600 million years ago (m.y.a.). The oldest fossil of a living
organism is 3.5 billion years old (3500 m.y.a.).
Task 1: Timeline of Life on Earth
Arrange the cards at your table in the order that you think they appeared in the fossil
record. Use the pictures, descriptions on the back of each card, graph about oxygen rising,
and the timeline below to help you. (Hint: Some billion year markers will not have
organisms)
As you work, think about this essential question:
What makes an organism more or less complex?
Timeline of Life:
1
Changing Times Changing Organisms Activity Sheet (Honors)
Name_____________________________
Date______________ Per._____
1. Generate a theory on what makes organisms less complex and more complex. (In your
own words and a complete sentence)
Share theories as a class.
Task 2: Classifying Life on Earth
Words to know as you go:
Mammary gland- gland to produce milk to feed infants
Ectothermic (Cold-blooded)- blood must be warmed by environment
Endothermic (warm-blooded)- Blood is warmed by body heat
Live birth- newborn grows inside the mother and is born alive
Vertebrate- Animal has a backbone and spinal cord
Photosynthetic- conducts photosynthesis
Eukaryotic- cell with a nucleus and membrane-bound organelles
prokaryotic- cell without a nucleus and membrane-bound organelles
Now that we organized organisms in a timeline of life based on their complexity, let’s plot
them in a way that shows how organisms are related and change overtime. In evolutionary
biology we use a phylogenetic tree or cladogram.
To make a cladogram, begin by collecting data on the organisms. Use the chart below to
collect data on the organisms you arranged in your timeline. Mark an ‘X’ for ‘yes’ traits
and (--) for ‘no traits’. If an organism has two similar characteristics, (ex. amphibians have
hair or fur) mark an ‘X’ for both traits.
2
Changing Times Changing Organisms Activity Sheet (Honors)
Name_____________________________
Traits:
Genetic
Prokar Eukar
Character
yote
yote
Trait
Photosynt X
X
hetic
Nucleus
X
Membrane
X
-bound
organelles
Unicellular
Multicellular
Vertebrate
(backbone
)
Lays eggs
Live birth
Gills
Lungs
Four legs
Mammary
glands
Skin:
Scales
Skin:
Feathers
Skin: Fur
Total “yes”
Date______________ Per._____
1st
Multicelled
X
Fish
X
X
X
X
Amph
ibian
Reptil
e
Bird
Mam
mal
Total
“yes”
3
X
X
X
X
X
X
X
X
7
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Understanding Cladograms
Words to know as you go:
Cladogram- Diagrams used to show phylogenies
Phylogenetic tree- another word for a cladogram
Phylogeny hypothesized evolutionary history between species based on physical traits,
biochemical traits and fossil records.
Divergence- When a common ancestor evolves into tow or more distinct species
Node- area on cladogram where two or more species share a common ancestor
3
Changing Times Changing Organisms Activity Sheet (Honors)
Name_____________________________
Date______________ Per._____
Outgroup- species that is most closely related to the common ancestor (most primitive
organisms in a cladogram)
Branch- extension of a cladogram devoted to a specific species
Derived trait- trait that is favored by evolution, leads to a diverse species, and trait not
found in the outgroup
Shared derived trait- trait that is shared between two or more species that was favored
by evolution, leads to diverse species, and distinct from the outgroup
Mammary glands- glands that produce milk for infant offspring
Speciation- When a new species is formed due to evolution
Interpreting a Cladogram
First, let’s practice interpreting some cladograms. Looking at the image and answer the questions
below.
1. Which species is the outgroup?
a. lizard
b. mouse
c. hagfish
d. chimp
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Changing Times Changing Organisms Activity Sheet (Honors)
Name_____________________________
Date______________ Per._____
2. After which animals did mammary glands develop?
a. hagfish
b. mouse
c. pigeon
d. salamander
3. What animal does not have jaws?
a. perch
b. hagfish
c. monkey
d. pigeon
4. Which animals have lungs?
a. salamander
b. pigeons
c. hagfish
d. Both a. and b.
5. What character trait separates salamanders and lizards?
a. feathers
b. mammary glands
c. lungs
d. claws or nails
6. List at least one shared derived character and explain who it is shared by.
7. List at least one derived character and explain why.
8. Based on the cladogram, which shared a common ancestor most recently?
a. a mouse and a lizard
b. a mouse and a perch
c. a mouse and a hagfish
9. What evolutionary event occurs when a species branches off from the main line?
a. speciation (new species evolves)
b. extinction (species dies)
c. endangered species status (species in danger of dying out)
5
Changing Times Changing Organisms Activity Sheet (Honors)
Name_____________________________
Date______________ Per._____
Practice Timeline Cladogram
Connect the timeline organisms from least to most complex on the cladogram
provided:
Most ancient
Most recent
Label: a) names of organisms, b) character traits that lead to a divergence
(see example cladogram above for help).
Practice:
Use this evidence diagram of embryos to make a cladogram showing the relationship
between fish, salamander, tortoise, chicken pig, cow, rabbit, and human.
Include: a) names of organisms b) 8 nodes branching from a common ancestor
(see example cladogram above).
6
Changing Times Changing Organisms Activity Sheet (Honors)
Name_____________________________
Date______________ Per._____
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