Plant and Animal Life Cycles, Gr. 2

 Plant and Animal Life Cycles, Gr. 2  

In this unit, students study the properties of living things. By the end of the unit, they compare plants and animals to see what properties they have in common and what properties are unique to plants or to animals. One thing that can be confusing to students is the concept of food.

All living things burn food by combining it with oxygen to release energy. This use of food is officially called respiration. Animals get their food by eating. Green plants actually make their own food using chemicals from the air and water and energy from sunlight. Both animals and plants also need nutrients to be healthy. These are not used to provide energy but are needed for different processes to work right in the plant or animal. When talking about animals, we call these nutrients vitamins and animals get them from the food they eat. When talking about plants, they are called nutrients or mineral nutrients and plants get them in the water they take in from the soil. If there are not enough nutrients in garden soil, gardeners often add fertilizer. Fertilizer is sometimes called plant food but it is not really a food because it can not be "burned" by the plant to release energy.

For Plants:

Tip: Some schools do not allow the use of bleach in any form. When preparing the germination bags in Activity 5, you can dip the seeds in a 3 percent solution of hydrogen peroxide to prevent mold instead of using bleach.

Visit Gardener's Supply - Gardening Information for indoor and outdoor gardening resources.

If students want to try growing seeds from some of the fruits in their lunches, visit our page on "Mistreating Seeds" for tips for getting them to grow.

Solve mysteries at the Great Plant Escape. Why do many plants have leaves? Why do many plants have flowers?

Iowa State University Extension's Home Horticulture site is useful for indoor and outdoor gardening information.

See also our From Seed to Plant page.

For animals:

Milkweed bugs are found on milkweed plants and have a life cycle that is a little different from the insects students usually study. The milkweed bug is considered a regulated organism by the US Department of Agriculture and can not be released. Please drown them in soapy water or freeze them at the end of the unit.

Tip: When setting up the milkweed bug culture, put just a spoonful of sunflower seeds in the bottom of the container. Tape the water source down with a loop of tape underneath to keep it from tipping over. You may also want to tape the lid on the water source. Spilled water in the culture container can cause mold to form in the culture. Some classes find putting a damp cottonball in the water source instead of using the wick and lid is a good way to avoid water spills.

Tip: Cleaning the milkweed bug culture container is easier than it may seem. Wait until the culture container is looking very soiled. Set up the new container with seeds and water source. Transfer the nylon netting, the cotton ball, and the lid of the culture container to the new culture. Most of the milkweed bugs will now be moved to the new culture. If you have at least half of them, you could drown the rest in soapy water in the old culture container. Generally, the lid does not require washing. Since these insects take about a month to mature, you should only have to clean the culture two or three times.

Mealworms are the larvae of the Darkling Beetle. The basic biology of mealworms is summarized on a page on TeacherNet. Visit Raising Mealworms for tips on how to take care of them. For information about beetles visit a website about Coleoptera or beetles.

There are a number of excellent general websites for insects. These include:

  • Bugbios
  • Entomology for Beginners
  • Minibeasts Fieldtrip
  • Using Live Insects in Elementary Classrooms
    View text-based website