Butterflies undergo complete metamorphosis during their life cycles, which means they pass through four distinct development stages: egg, larvae, pupa and adult. During the summer months, you can organize a trip to a nearby garden or forested area to observe milkweed that may containing eggs, larvae or pupa of the monarch butterfly. Eggs are white and small and are often located on the underside of the leaves. As eggs hatch in three to five days, go back daily to observe the changes that occur in their coloration and size. Students can record all stages of the development of the monarch butterfly in daily charts and also by using drawings.
Fruit flies (Drosophila melanogaster) have short life cycles, which can last for only 20 days. You can test how temperature interferes in the life cycle and development of fruit flies. As adults are sometimes more difficult to capture, you can collect maggots often found in decaying fruit. Create two glass vivariums to put your collected maggots or flies. Cover them with a thin mesh. While keeping one of them at normal ambient temperature, increase the temperature in the other by placing two lamp bulbs on its top. Students can observe the differences in the development of the insects day by day.
Organize a trip with the students to a nearby pond to collect tadpoles by placing them in a big jar or fish tank. Provide food to the young frogs by adding algae or other organic material found at the pond into the jar or tank. Using drawing, video or photography, students may record the the development of the rear legs first and the front legs later. They will create hypotheses to explain this order of events. At the same time, they will observe the shrinking of the tail and gills. They will compare hypotheses and check bibliographic references to see if hypotheses are correct.
Students in the second or third grade can investigate the life cycles of different mammal species during a guided visit to a farm. First, check what is the best time of the year to see young animals, such as lambs, chicks and piglets. Create an individual form or chart where students can write the name of the animals observed, number of offspring, age of both mothers and babies, as well as other relevant information you can later use in the classroom to create a comparative panel. Students can also photographs or draw the animals.