1. LOOKING AT PLANTS AND ANIMALS
LIFE SCIENCE
Third Grade

2. Vocabulary Preview organism,A6 leaf,A18 reproduction,A7 energy,A18
environment,A oxygen,A19
respond,A life cycle,A26
cell,A embryo,A26
mineral,A heredity,A27
root,A flowering plant,A28
stem,A conifer,A28

3. FEATURES OF LIVING THINGS
Grow and change
Reproduce

4. Smaller Parts of Living Things
Plant Cells
Cell membrane
Nucleus
Cytoplasm
Cell wall
chloroplast
Animal Cells
Nucleus
Cytoplasm
Cell membrane

5. The Needs of Plants Review Vocabulary Mineral, A16 Root,A17 Stem,A17
Leaf,A18
Energy,A18
Oxygen,A19

6. Basic Needs Minerals Sunlight Water Air leaves stems
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roots

7. Why Does A Plant Need Leaves?
Leaves are the main food-making part of the plant.
Leaves take in sunlight.
Leaves are green because of chlorophyll.
Chlorophyll traps the energy in sunlight for the plant.
Leaves also help the plant get the air it needs.
It uses carbon dioxide from air.
The plant uses the Sun’s energy to combine carbon dioxide
and water to make food.
8. Plants use food to stay alive and give off oxygen.

8. How Do Plants Respond To Their Environment?
One way plants respond
is by growing toward the
sunlight.
Trees respond to cooler
weather when their leaves
turn color.

9. Why It Matters
We depend on plants for food. We eat the roots,
Stems, and leaves of plants. The cereals we eat
Are made from plants. We eat animals that eat
Plants. However, people need plants for more
Than food. We also breathe the oxygen that plant
Leaves make.

10. The Life Cycle of a Plant
Vocabulary Preview
Life cycle,A26
Embryo,A26
Heredity,A27
Flowering plant,A28
Conifer,A28

11. How Does a Plant’s Life Begin?
A seed begins a plant’s life cycle. A plant
begins life, grows, develops, reproduces,
and dies.

12. Think On a cold day, you might see icicles that have grown
from the roof of a building. Does this mean icicles are
living? Explain.