Life Cycling On-site Activities

Grade Level: 2
Content Area: Science
Time to Complete: 2 hours in structured program; 1½ hours on trail around lake doing life cycling stations at posts
Title of Lesson: Life Cycling In and Around the Lake

Students investigate life cycles in and around Lake Placid, and or/Mountain Creek. In the park lab, they discuss the life cycles of a variety of lake and stream animals, and the needs of animals at various points in their life cycle. They compare those that resemble their parents right after birth to those that go through metamorphosis. They collect animals at the lake, including dragonfly nymphs, fish, and other aquatic animals, including possibly tadpoles and salamanders. They also take temperature measurements and measure the length of animals found. Back in the lab, students observe the animals collected under the microscope, noticing adaptations to their environment, such as gills. Finally, students classify them according to their life cycle stage. The importance of good habitat with clean water is emphasized.

Paris Mountain is located in the northeastern part of Greenville County, within the piedmont region of South Carolina. It is the southernmost extension of the Blue Ridge mountains. The area is a watershed: a region in a green mountain valley, where water drains into a common area, often a river or lake. Lake Placid is one of four lakes in the park, created in the 1890s as a source of drinking water for the people of Greenville. The park land has been protected since the 1800s, originally to protect the drinking water. The protection of forests around an aquatic area prevents muddy run-off, pollution, and flooding, with rainwater being slowly filtered through the forest soil, into the lakes and streams.

The students will be scientists, studying life cycles of animals in the park. Initial discussion will focus on animals that go through metamorphosis (to change in form during growth), versus those that resemble their parents at birth. Some insects, like dragonflies and mayflies, go through a three-stage metamorphosis: egg, nymph and adult.

Other insects, such as beetles and craneflies, go through a four-stage metamorphosis: egg, larva, pupa, adult. Students are likely to find each of these animals while collecting at the park.

After using nets to collect animals in Mountain Creek, students will measure the temperature of the air and water. They will also use a 6-inch ruler to measure the length of some of the animals found in the water. When studying life cycles of cold-blooded animals, like insects, amphibians, fish and reptiles, temperature plays a major role in their growth and development. Growth is determined by temperature and food supply. Each species of animal in a particular habitat (for example, the Eastern pond hawk dragonfly at Paris Mountain State Park), has an optimum temperature in which its larva stage, which lives underwater in Lake Placid, will grow quickly. Beyond a certain temperature, development stops. Depending on temperatures in a region of the country, a dragonfly can take from 1 to 5 years to become an adult. Adult dragonflies must wait until the air warms to a certain temperature before it can fly each day. Temperature can even determine if a water turtle hatches as a male or a female. A warmer nest results in more females.

When you have a sample of animals that are the same kind, and living in the same habitat, you can compare their sizes to guess which is youngest and which is oldest. This can be done by measuring length with a ruler. Often, the point at which an animal, such as a dragonfly nymph, metamorphoses into an adult, is determined by how large it grows.

If a dragonfly nymph or other nymph does not reach its largest size before cold temperatures set in for the winter, it will over-winter in the water as a nymph and continue growth in the spring.

Good water quality is needed at all stages of an animal’s life cycle. A toad in the woods needed good water as an egg in a lake, as a tadpole in a lake, and then as an adult in the woods. Adult toads get water through their skin, while sitting in moist areas on the ground.

1.	Students are introduced to the park and its role as an ideal place to study a variety of life cycles. Students are also introduced to their role as scientists. Safety rules for themselves and for the park are discussed. Note: If two classes, one class will go around the lake with a Volunteer Naturalist, experiencing a life cycling nature hike based on state science standards. Activities and/or discussion are involved at each of seven stations. A kit covering the points of the life cycling hike is available, and can be used by the teacher if a volunteer is not available. After lunch, the two classes will switch.
2.	With Park Interpreter, class walks to a sitting area, for a discussion about metamorphosis, and the importance of temperature in determining how fast a cold-blooded animal (such as a dragonfly nymph) grows. The importance of good water quality (and how forests contribute to good water quality), at all stages of an animal’s life cycle are discussed. Students are given a clipboard with a life cycling data sheet.
3.	With Park Interpreter, class walks down to creek, observing life cycles along the way (e.g. tadpoles in lake, insect galls on leaves, caterpillars on plants, variable by season).
4.	Class is divided into two groups. One group uses nets to collect animals in the water. The other group starts measuring air and water temperature, and filling out their data sheets. They draw one animal found in creek, use a 6-inch ruler to measure the length of the animal, and identify the animal including its life cycle stage.
5.	Class walks up to the lab with their pans of aquatic animals. Using a microscope and video monitor, the class observes the magnified organisms, noting structures that help them survive in their aquatic environment, and discussing their life cycle stages. The role of the forest in creating suitable habitat at all stages of life is discussed: the forest prevents erosion, pollution, and drought in the stream and lake, and becomes a home for some of the animals after they leave the water.