Natural environmental changes can take a really long time. Deserts
and mountains can take millions of years to form. Other
environmental changes can be quick like when a river floods because
of heavy rain. People can also change the environment quickly by
building dams and cutting down trees.
When the environment changes, plants and animals living in that
environment must respond to those changes in order to stay alive.
Environmental
changes affect the survival of entire
populations of plants
and animals. Sometimes a species will die out, or go
extinct, when the environment changes too rapidly. If the change is very
slow, plants and animals can adapt to the new environment.
Sometimes, a new species
evolves
that is adapted to the new
environment.
In this activity, you will speed up time and
watch Mystery Plants grow in a changing environment.
Will they
go extinct or will they evolve?
Experiment: Mountain range
It takes millions of years for a mountain range to form, way too
long to see in real life. In this experiment, you will plant Mystery
Plants and speed up time to see what happens when mountains form.
What will happen to the Mystery Plants as the mountains get higher
and higher?
Instructions
1. Click the plant
button to plant lots of seeds. Click the Play button
to
start growing the plants.
2. Move the slider up to watch the
mountains grow taller. Click the Reset button
to
clear all the plants and mountains and start over. Run the model as
many times as you want.
Take a picture after the mountains
have formed. Describe what happened to the plants in your Lab Book.
Mountain height:
High
Low
fallPlants1. What happened to the environment on each side of the mountain as the mountains grew taller?Both sides of the mountains stayed the same.Both sides of the mountains became more sunny.One side of the mountains became more sunny and the other side became more shady.Both sides of the mountains became more shady.One side became sunnier and the other side became shadier.2. What happened to the plants when the mountains grew quickly?The plants and their babies died.
Extinction: What happened?
You sped up time and watched what happened to the population of
Mystery Plants when mountains formed in their environment. The
mountains rose in the middle and the environment on each side
changed. If the environment changed too quickly, the plants all died.
One
way for plants or animals to survive a change in environment is to
adapt to the new environment. This takes a long time! On the next
page, your challenge will be to see if Mystery Plants can adapt if
the environment changes very slowly.
Challenge: Help the Mystery Plants survive
Do you think the population of Mystery Plants will be able to adapt
to the new environments on each side of the mountains if the
mountains change more slowly? Here is your chance to find out!
Instructions
1.
Click the plant button to plant lots of seeds. Click the Play button
to
start growing the plants.
Take a picture of the plants when there
are no mountains.
2. Move the slider up and watch the
mountains grow taller. Click the Reset button
to
clear all your plants and mountains and start over. Run the model as
many times as you want.
Then take a picture when the mountains
are highest.
3. Compare the plants when there are no
mountains to when there are tall mountains. Use the the Information
button
and
the graph.
Mountain height:
High
Low
fallPlants
Populations: Changes over time
Did your Mystery Plants go extinct or evolve?
Leaf size 10
Leaf size 6
Leaf size 2
3. What happened to the population of plants as the environment changed slowly?They evolved into other plants that were slightly different.4. Open your Lab Book. Compare the plants and environment before and after the mountains grew.When there were no mountains, all the plants looked the same. After the mountains grew, one side of the mountain was sunny and the other side was shady. The plants on one side were the big leaf plants and the plants on the other side were the thin leaf plants. The medium leaf plants, which were there originally, went extinct.5. Which plants grow best on side A?Leaf size 2 PlantsLeaf size 6 PlantsLeaf size 10 Plants6. Which plants grow best on side B?Leaf size 2 PlantsLeaf size 6 PlantsLeaf size 10 Plants
Common Ancestors: Mystery Plants
The medium leaf Mystery Plant was able to adapt to the change in the
environment if the environment changed very slowly. If the
environment changed slowly, variations in the baby plants helped
some of the babies grow better in the new environment. If the
environment changed too quickly, the plants died.
The medium
leaf plant evolved into two different species, a larger leaf plant
that grows well in a shadier environment and a smaller leaf plant
that grows well in a sunnier environment. The medium leaf plant went
extinct, but it is the
common ancestor
of the two new plants.
Remember, when a population of plants or animals evolve, it takes
many, many years. One particular plant or animal doesn't change. For
example, the plant on your teacher's desk does not become a new
plant. Over a long time, small changes in a whole population of
plants or animals can happen. These changes happen because of
natural variation in the offspring. Some plant seeds have traits
that give them a small advantage over their brothers and sisters.
They grow and produce seeds of their own, passing along these
traits.
7. Why did the medium leaf plant go extinct?The medium leaf plant went extinct because the environment changed. The environment no longer supported this type of plant.
Common Ancestors: Elephants and manatees
Elephants and manatees may not look alike, but they are related!
They share a common ancestor that lived on land. Their ancestor went
extinct millions of years ago, but evolved into other species.
Elephants stayed on the land while manatees evolved to live in
coastal waters.
This drawing shows a possible common ancestor.
Manatee
Elephant
There are many interesting similarities between the two animals.
Manatees even have toenails on their flippers!
Manatee Flipper
Elephant Foot
8. Why do you think manatees have toenails on their flippers?
Conclusion
On Earth, there have been a few times when the environment changed
too quickly for most plants and animals to adapt to the new
environment. For instance, scientists believe that a long time ago,
a giant meteor hit the Earth and caused a mass extinction of the
dinosaurs. The dinosaurs could not live after the meteor because
their environment was not the same. When the environment has
changed slowly, new species have time to evolve.
You have
completed Activity 3. Good job! Click the X at the top of this
window to close the activity and save your work.