Student Investigation Journal

The Forest Beyond the Flood

Ecology & Speciation

Student Name

Class Period

Date

Part 1: The Isolated Creek & First Contact

Rollins and Kevin had been best friends since the third grade. Every Saturday morning, they explored the woods near their neighborhood in East Texas. They carried backpacks filled with snacks, water bottles, notebooks, and a small pair of binoculars that Rollins had received for his birthday. The boys loved science, especially animals and nature. They hoped one day to become wildlife biologists.

One cool spring morning, Rollins rushed to Kevin’s house with excitement.
“Kevin! Come on! My uncle said the creek is lower than it’s been in years. We can finally cross into the flooded forest!”

Kevin grabbed his backpack and ran outside. Four years earlier, a massive flood had swept through the region after weeks of nonstop rain. The rushing water destroyed bridges, uprooted trees, and separated part of the forest from the rest of the land. Since then, the isolated area had remained difficult to reach.

The boys followed the narrow trail until they reached the creek. Fallen trees now formed a natural bridge across the shallow water.

“This used to be too deep to cross,” Kevin said.
“Not anymore,” Rollins replied with a grin.

The boys carefully crossed and entered the isolated section of the forest. The trees looked different there. Thick vines twisted around trunks, and patches of bright moss covered the ground.

Suddenly, Kevin froze. “Did you see that?” A small animal darted across a branch. “It looked like a squirrel,” Rollins whispered, “but something seemed strange about it.”

The boys crouched behind a bush. A group of squirrels leaped through the trees, but they did not look like ordinary gray squirrels. Their fur had a dark reddish-green tint that blended into the mossy forest. Their tails were thinner, and their front teeth looked longer and sharper.

Field Observation

Rollins and Kevin noted critical changes in this population:

Reddish-green tinted fur
Thinner, streamlined tails
Longer, sharper incisors
Smaller ear structure
Diet includes amphibians (frogs)

Key Term Spotlight

Isolation: The complete separation of a population of organisms from others of the same species, preventing interbreeding.

Unit: Ecology & Speciation Page 1 Topic: Geographic Isolation

Student Work Packet

Name: ______________________

Field Notes Analysis: Part 1

1. Who were the two boys that discovered the new squirrel species? Explain their background interest.

2. What natural disaster caused the squirrel population to become isolated in this specific forest?

3. How long had the squirrels been isolated from the other squirrel population before Rollins and Kevin crossed over?

4. Describe at least three distinct physical differences the boys observed between these squirrels and normal gray squirrels.

5. What unusual food did the swamp squirrels begin eating that shocked the boys during their observation?

Unit: Ecology & Speciation Page 2 Topic: Field Notes Analysis 1

Student Investigation Journal

The Science of Speciation

Genetic Drift & Selection

Part 2: The Investigation & The Genetic Code

The boys quietly observed the animals for nearly an hour. The squirrels moved differently than normal squirrels. They jumped lower to the ground, searched near ponds, and hunted frogs hiding beneath wet leaves. When Rollins snapped a photo with his phone, one squirrel stood upright and made a sharp clicking sound unlike any squirrel call they had heard before.

The next Monday, the boys showed their science teacher, Mrs. Hernandez, the photos and notes. Mrs. Hernandez contacted a wildlife research team at a nearby university. Within days, scientists arrived with Rollins and Kevin guiding them.

Dr. Samuel Greene, a mammalogist, carefully examined the squirrels. “Incredible,” he whispered. “I’ve never seen squirrels behave like this.” Over several weeks, scientists trapped several squirrels safely for testing. They discovered the squirrels had changed rapidly over the four years since the flood.

Because the forest became wetter after the flood, many nut-producing trees died. The isolated squirrels struggled to survive. Over time, they adapted to their environment by eating frogs, insects, and small wetland animals. The squirrels with sharper teeth and stronger jaws survived better and passed those traits to their offspring.

Scientists also discovered genetic differences. The isolation caused the squirrel population to stop breeding with outside squirrels. Eventually, enough changes occurred that they became a completely new species: Sciurus amphibionis, nicknamed “Swamp Squirrels.”

Scientific Process

How did Sciurus amphibionis emerge in just four years?

1 Barrier: Flooding isolates the population.
2 Pressure: Oaks die; food source becomes scarce.
3 Selection: Sharp-toothed frog hunters survive.
4 Speciation: Breeding stops; genetic separation occurs.

The Path of Speciation

Step A: Isolation

A geographical barrier (floodwater) divides one parent population into two separate groups.

Step B: Adaptation

Natural selection favors individuals with traits suited to the wet environment.

Step C: Speciation

Sufficient genetic mutations accumulate so populations can no longer interbreed.

Unit: Ecology & Speciation Page 3 Topic: Evolutionary Adaptation

Student Work Packet

Name: ______________________

Scientific Analysis: Part 2

6. Why did scientists believe the isolated squirrels had changed enough to be classified as a completely new species? What did they find during genetic testing?

7. What specific scientific term describes the process of one species changing and branching into a completely new species over time?

8. Explain the role of natural selection in the development of the swamp squirrels. Which individuals survived better, and why?

9. How did Rollins and Kevin help the professional university scientists study this new species? What does this tell you about citizen science?

Unit: Ecology & Speciation Page 4 Topic: Field Notes Analysis 2

Student Investigation Journal

The Ecological Ripple Effect

Invasive Species Study

Part 3: The Threat of the Invasive Swamp Squirrels

At first, everyone celebrated the new species. Environmental groups wanted to protect the isolated forest habitat. However, problems soon began appearing. The swamp squirrels multiplied quickly. Since they had few predators and plenty of frogs to eat, their population exploded.

Within months, the squirrels spread beyond the isolated forest into nearby wetlands and neighborhoods. Biologists noticed frog populations dropping rapidly. At a local pond, researchers counted almost half the normal number of frogs.

“This could become dangerous for the ecosystem,” Dr. Greene warned on TV. Frogs played an important role in controlling insects such as mosquitoes. Without enough frogs, mosquito populations increased dramatically. People complained about bites and swarms around homes.

One evening, Rollins and Kevin returned to the forest with Dr. Greene. The forest sounded quieter. “There used to be frogs everywhere,” Kevin said softly. Dr. Greene nodded. “Invasive species can upset the balance of an ecosystem very quickly.”

Rollins looked worried. “But these squirrels belong here now, don’t they?”

“They evolved here,” Dr. Greene explained, “but because they spread so rapidly and began harming other species, they became invasive in nearby ecosystems.”

Months later, Rollins and Kevin stood before their classmates at the school science showcase, explaining the process. After the presentation, a student asked, “So… discovering a new species is cool, but can it also be dangerous?” Rollins nodded. “Yes. Nature is all connected. Even exciting discoveries can affect ecosystems in unexpected ways.”

Ecosystem Impact

The introduction of an invasive species creates a cascade effect:

1. Predator Explosion Swamp squirrel population grows without biological controls.

2. Prey Depletion Frogs are overhunted, resulting in a 50% population collapse.

3. Pest Surge Mosquitoes multiply rapidly, affecting surrounding neighborhoods.

Unit: Ecology & Speciation Page 5 Topic: Ecosystem Dynamics

Student Work Packet

Name: ______________________

Ecosystem Analysis: Part 3

10. Why did the swamp squirrels become considered an invasive species, even though they evolved naturally in that Texas forest?

11. How did the growing swamp squirrel population affect the local frog population? Provide specific details from the text.

12. Why are frogs important to this East Texas ecosystem? What happened when their numbers dropped?

Trophic Cascade Diagram

Fill in the boxes with key ecosystem responses based on the reading:

1. Cause

Swamp Squirrel population explodes

2. Direct Effect (Prey)

3. Indirect Effect (Pest)

Unit: Ecology & Speciation Page 6 Topic: Trophic Cascades

Student Work Packet

Name: ______________________

Personal Explorer Reflections

13. What would you do if you discovered a completely new species in a forest near your home? Who would you contact first?

14. How would you handle the attention from news reporters and television stations if you became famous overnight for a scientific discovery?

15. What would you do if the species you discovered started harming the local environment or surrounding neighborhoods?

16. How would you feel if scientists officially named a species after you or something you discovered? Why?

17. If you were Rollins or Kevin, would you continue studying wildlife after this intense experience? Explain your reasoning.

Unit: Ecology & Speciation Page 7 Topic: Explorer Reflections

Swamp Squirrel Student Packet

Swamp Squirrel Student Packet

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