Chapter 1
Earth Science
Course: Elementary Education Multiple Subjects 5001
Subject: Elementary Education Science Subtest 5005
Chapter: Life Science
1. Characteristics of Living Things
Living organisms can be identified by specific characteristics that separate them from non-living things. These characteristics are universal across all forms of life, from simple bacteria to complex animals and plants.
Cellular organization
All living things are composed of one or more cells. Cells are the smallest units capable of carrying out life processes.
- Unicellular organisms consist of a single cell that performs all necessary functions (e.g., bacteria, amoeba).
- Multicellular organisms have specialized cells grouped into tissues, organs, and systems (e.g., humans, oak trees).
Metabolism
Metabolism is the sum of all chemical reactions occurring in an organism. These reactions allow organisms to obtain and use energy.
- Example: In humans, food is broken down in the digestive system, converted to glucose, and used in cellular respiration to generate ATP (energy). The waste products are then excreted.