Life in the Dark
These activities align with the following National Science Education Standards: Content Standard C: Life Science–Regulation and Behavior; Populations and Ecosystems; and Diversity and Adaptations of Organisms.
Part 1 –Adaptations
Like all living things, cave animals are adapted to their environment. Structural adaptations involve some part of the animal's body, while behavioral adaptations are actions that help the animal survive. By filling in the blanks on an adaptation chart, students can learn about the kinds of adaptations cave animals possess.
1. Create a chart on a chalkboard or pad of easel paper with the following headings across the top: Animal; Adaptation; Structural/Behavioral; Advantage.
2. Have your students look closely at the animals illustrated on the poster and note the type of animal in the left-hand column of the chart.
3. Next, have them list in the second column at least one adaptation for each animal, such as the claws on the bat, the long antennae of the cricket and crayfish, or the web-making ability of the spider.
4. In the third column, students should identify whether the adaptations they have listed are structural or behavioral adaptations.
5. The fourth column should be used to note student suggestions about the advantages that each adaptation would provide to the animal.
Note: Depending on the age and abilities of your students, you may want to fill in some parts of the chart in advance. For instance, you could list the adaptation "echolocation" for bats and allow students to come up with the type of adaptation it is and the advantage(s) it provides. Alternatively, you could list a particular advantage for an animal and ask students to suggest an adaptation that provides it.
Extension: Encourage students to research cave animals other than the ones shown on the poster, and have them create adaptation charts for these additional animals. They could consult encyclopedias, books, or the following website:
Part 2 –Web of Life
As the article states, the number and variety of organisms living in a cave are small compared to populations in aboveground ecosystems. As a result, the natural balance existing in a cave can be easily upset. By creating cave food chains and discussing possible scenarios, students will come to realize how fragile cave ecosystems are.
1. Have your students create examples of cave food chains from the list of organisms below. Students can also create their own lists by consulting the website mentioned above. An animal encyclopedia might also come in handy, so students can research cave animal diets.
- nuts & seeds
- leaves & twigs
- guano (feces of bats)
- cave cricket
- cave crayfish
2. Once the class has developed an assortment of food chains, ask students to identify producers, consumers, and decomposers.
3. Next, discuss some of the following scenarios. Have students consider what might happen to the cave food web in each of these situations.
- A drought or wildfire on the surface kills most vegetation surrounding the cave. Little or no plant material blows or is washed in through the cave entrance.
- A predator such as a raccoon takes up temporary residence in the cave and eats all the crayfish in the cave's tiny pool.
- Human visitors leave trash, including spent batteries and remains of their lunch, inside the cave.
- A gate is installed to keep people out and protect the cave, but the gate also keeps out bats and wildlife and restricts the flow of air and water into the cave.
- Groundwater pollution kills cave shrimp and crayfish.
Adapted with permission from Project Underground.