This worksheet will help you understand the key characteristics that define living organisms. Use it to test your knowledge and learn more about what makes something "alive."
What Makes Something Alive? A Closer Look at the Characteristics of Life
All living things share several key characteristics. Let's explore them!
Instructions: For each characteristic below, provide a brief definition and give at least one example of how that characteristic is demonstrated in a living organism.
| Characteristic of Life | Definition | Example |
|---|---|---|
| Organization | Living things are highly organized, from the level of atoms and molecules to cells, tissues, organs, and organ systems. | A plant's organized structure, from cells forming tissues, to tissues forming leaves and stems. |
| Metabolism | The sum of all chemical reactions occurring within an organism to maintain life. | Photosynthesis in plants (converting light energy into chemical energy). Cellular respiration in animals (breaking down food for energy). |
| Growth | An increase in size or number of cells. | A seed germinating and growing into a plant. A child growing taller. |
| Adaptation | The ability to adjust to changes in the environment. | A cactus developing thick stems and spines to survive in arid environments. Camouflage in animals. |
| Response to Stimuli | The ability to react to changes in the internal or external environment. | A plant bending towards sunlight (phototropism). An animal running away from danger. |
| Reproduction | The ability to produce offspring. | A bird laying eggs. A human giving birth. Bacteria splitting into two. |
| Homeostasis | Maintaining a stable internal environment despite external changes. | Sweating to regulate body temperature in humans. A plant closing its stomata to conserve water. |
People Also Ask (PAA) Questions & Answers
Here are some frequently asked questions about the characteristics of living things, with detailed answers to help deepen your understanding:
What is the difference between growth and development?
Growth refers to an increase in size or number of cells. Development, on the other hand, involves the progression through different stages of life, accompanied by changes in form and function. While a human baby grows larger, it also develops by learning new skills, growing its brain, and undergoing physiological changes. Growth is a quantitative change, while development encompasses both quantitative and qualitative changes.
How does adaptation differ from evolution?
Adaptation is a characteristic that enhances an organism's survival and reproduction within its environment. Evolution, however, is the change in the heritable characteristics of biological populations over successive generations. Adaptation is a process that contributes to evolution. For example, the long neck of a giraffe is an adaptation that allows it to reach high branches. Over generations, the giraffes with longer necks were more likely to survive and reproduce, leading to the evolution of the long-necked giraffe population.
Can a virus be considered a living thing?
This is a complex question that often sparks debate. Viruses possess some characteristics of living things, such as organization (genetic material encased in a protein coat) and reproduction (though they require a host cell to reproduce). However, they lack other key characteristics, such as metabolism and homeostasis. Therefore, whether or not viruses are considered living is a matter of ongoing scientific discussion and depends on how strictly one defines "life."
What are some examples of homeostasis in plants?
Plants maintain homeostasis through various mechanisms. Closing stomata to reduce water loss during drought is a key example. Other examples include regulating the opening and closing of flowers to optimize pollination, and adjusting the concentration of solutes within their cells to maintain osmotic balance.
This worksheet provides a foundation for understanding the characteristics of life. Remember to consult further resources for a more in-depth exploration of this fascinating topic.
