Warm Up to Science:
TEKS-Based Engagement Activities for Grade 7
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79: Odd One Out—Levels of Organization
TEKS 7.12C
Reporting Category: Organisms and Environments
TEKS
7.12C: The student is expected to recognize levels of organization in plants and animals, including
cells, tissues, organs, organ systems, and organisms.
Answer
1. brain, red blood cell, lung, skin (not an organ)
2. circulatory, respiratory, nervous, liver (not an organ system)
3. heart, elephant, human, tree (not an organism)
4. blood, cell membrane, chloroplast, cell wall (not a cell organelle)
5. esophagus, eye, stomach, small intestine (not a digestive system organ)
6. heart, white blood cell, neuron, red blood cell (not a cell)
7. bacteria, grass, cats, fish (not multicellular/not eukaryotic)
Teacher Notes
Living things are made of one or more cells. Bacteria are examples of one-celled, or unicellular,
organisms. All of the functions needed for life are performed by these unicellular organisms. In
contrast, multicellular organisms like dogs and humans contain many specialized cells that work
collectively in tissues. Tissues working together form an organ. Groups of organs working together
are an organ system. An organism contains many different organ systems.
