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Activity 4: Changes in the Environment
Introduction: Changing environments
Natural environmental changes can take a very 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 survive in the new environment over many generations. This process is called evolution.

In this activity, you will speed up time and watch Mystery Plants grow in a changing environment. Click the blue arrow to begin. Will the plants go extinct or will they evolve?
Click the blue arrow to begin.
Virtual Field: Same level of sunlight
So far you have planted Mystery Plants in a Virtual Greenhouse and in the Virtual Field. The field had areas with different amounts of sunlight. What happens to the Mystery Plants in a field that has the same sunlight all over?

Instructions

1. Click the plant button. Notice that one click plants several seeds in the field. Click the Play button to start growing the plants.

2. When the flowers drop seeds, pause the model, and use the Information Tool to learn more about the plants.
Your challenge: Find out why some of the offspring plants are wilted.

Mystery Plant variations
For a population of plants or animals to 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 grow bigger leaves if it needs more sun. It might wilt and die, but some of its seeds might grow into plants with larger leaves and be able to live in the same flowerpot.

In the Virtual Field model, you planted Leaf Size 5 Plants. The plants grew up, made flowers, and dropped seeds. Most of the offspring grew well in the Virtual Field, but some of the offspring did not grow well in that environment.





1. Why did some plants have flowers while others were brown and wilted? 2. If the environment became shadier, which plant would grow better? Offspring with slightly smaller leaves (Leaf Size 4) Offspring with the same size leaves (Leaf Size 5) Offspring with slightly larger leaves (Leaf Size 6)
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 in the middle of the Virtual Field. 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. Click the button for "Mountain height" to watch the mountains grow (remember: this would take millions of years in real life).

Your challenge: To get flowering plants on both sides of the mountains. Take a picture when you do.


Mountain height: High

Low
fall Plants http://otrunk.concord.org/examples/EvolutionReadiness/models/species/images/plants/varied-plants/flower10cropped.png http://otrunk.concord.org/examples/EvolutionReadiness/models/species/images/plants/varied-plants/flower5cropped.png http://otrunk.concord.org/examples/EvolutionReadiness/models/species/images/plants/varied-plants/flower1cropped.png
Extinction: What happened?
You watched Mystery Plants grow as mountains formed in the middle of their environment. Did you notice that the environment changed on each side of the mountains? Look in your Lab Book to answer the following questions.





Leaf Size 9
Leaf Size 5
Leaf Size 1

3. 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. 4. Which plants grow best on side A? Leaf Size 1 Plants Leaf Size 5 Plants Leaf Size 9 Plants 5. Which plants grow best on side B? Leaf Size 1 Plants Leaf Size 5 Plants Leaf Size 9 Plants 6. What happened to the population of plants as the environment changed slowly? The whole plant population went extinct. The parent plants changed their leaf size to grow better in the new environment. Some offspring that were different than their parents were able to survive in the new environment. 7. What happened to the plants when the mountains grew quickly? The offspring died.
Populations: Changes over time
Only over a long time can small changes in a whole population of plants or animals happen. These changes happen because of natural variation in the offspring. Some plant babies have traits that give them a small advantage over their brothers and sisters. The plants that live best in an environment have more babies. Those babies grow and produce seeds of their own, passing along these traits.






Graphing changes in the environment
As the mountain height changed, the environment on both sides of the mountains changed. What does this mean for the plants that lived there? These graphs show what happened to the plants as the mountains formed. Look at the graphs, then answer the questions below.










8. In Graph A, how many types of plants are there? 1 2 5 9. In Graph B, how many types of plants are there? 1 2 5 10. In Graph D, are there more Leaf Size 2 plants or Leaf Size 8 plants? More Leaf Size 2 More Leaf Size 8 Leaf Sizes 2 and 8 have the same number of plants. I don't know. 11. Look at all four graphs above. Tell a story to describe what happened to the plants when the mountains formed and the environment changed.
Common Ancestors: Mystery Plants
The Leaf Size 5 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 offspring helped some of them grow better in the new environment. If the environment changed too quickly, the plants died.

The Leaf Size 5 plant evolved into two different plants, 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.




12. Why did the Leaf Size 5 plant go extinct? More animals liked to eat the flowers on the Leaf Size 5 plants. The environment had the wrong level of sunlight for the Leaf Size 5 plant. There was too much water for the Leaf Size 5 plant to live.
Common Ancestors: Elephants and manatees
Just like plants, animals evolve over a long time as the environment changes. When the environment changes slowly, variations in a population of animals help them live under different conditions. Over a long time, animal bodies can adapt to live in different environments.

Did you know that elephants and manatees are related? They share a common ancestor that lived on land. Their ancestor went extinct millions of years ago, but evolved into other animals. Elephants are suited to live on 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



13. Why do you think manatees have toenails on their flippers? Because they use their toenails to scratch when they are itchy. Because they evolved from an ancestor that had toenails. Because they evolved from an ancestor that had a long trunk. Because they need toenails to swim.
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 the environment changed too quickly for them to adapt. When the environment changes slowly, new species have time to evolve.

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