What does it take to be a living organism?
Living things share 8 characteristics that are listed in Chapter 1 of your textbook on page 19. Think of an organism or cell in which all 8 characteristics are not obvious. For example, coral looks like it does not move, red blood cells do not reproduce and have no DNA, frogs freeze in the winter therefore it seems as if they do not maintain homeostasis, and so on.
Focus your discussion on the following:
• Make comparisons between living things and nonliving things that have some of the characteristics that define life.
• Compare the following pairs and explain what the differences are using the 8 criteria:
o A rock to a snail
o A rock to a tree
o A dog to a TV
• Explain why electricity is sometimes called live, or discuss some of the characteristics fire shares with living things (it can grow, it metabolizes, and so on).
To determine what it takes to be a living organism, we can refer to the 8 characteristics commonly associated with life. These characteristics are outlined in Chapter 1 of your textbook on page 19. Let's discuss an organism or cell where these characteristics are not apparent, and compare it to nonliving things that possess some of these traits:
1. Organization: Living organisms have a complex and organized structure. For example, comparing a rock to a snail, we can observe that the snail has a more complex organization. While the rock is composed of minerals arranged in a non-specific manner, the snail has distinct organ systems, such as a digestive system, a circulatory system, etc.
2. Energy Utilization: Living organisms require energy to carry out their functions. A rock, being inanimate, does not require energy for any biological processes, whereas a snail relies on energy from food to perform activities like movement, growth, and reproduction.
3. Homeostasis: Living organisms maintain a relatively stable internal environment despite varying external conditions. If we compare a rock to a tree, the tree exhibits homeostasis by regulating its temperature, maintaining water balance, and adapting to changing environmental factors. In contrast, a rock does not possess any mechanisms to maintain a stable internal environment.
4. Growth and Development: Living organisms grow and undergo developmental changes over time. A rock does not exhibit growth or developmental processes, while a tree grows in size, develops new branches, and produces leaves throughout its lifespan.
5. Reproduction: Living organisms have the capacity to produce offspring. In the case of a rock, it does not reproduce, whereas a snail can reproduce by laying eggs and fertilizing them.
6. Response to Stimuli: Living organisms can respond to changes in their environment, whereas nonliving things are unable to do so. A rock does not exhibit any response to stimuli, whereas a snail will respond to environmental factors such as temperature changes, predators, or food availability.
7. Adaptation: Living organisms can adapt and evolve over time in order to survive in their environment. In contrast, nonliving things lack the ability to adapt. For example, a snail can develop certain adaptations, such as a protective shell, to improve its chances of survival, while a rock remains unchanged and does not adapt.
8. Possession of Genetic Material: Living organisms possess genetic material that determines their characteristics and allows for the transmission of traits to offspring. While a rock does not possess genetic material, a snail has DNA that carries the necessary information for its growth, development, and function.
Now, let's discuss the idea of electricity being sometimes called "live" or the characteristics fire shares with living things:
Electricity is sometimes referred to as "live" because it exhibits some characteristics associated with life. Just like living organisms, electricity can grow (increase in voltage or current), reproduce (create duplicate circuits or connections), and metabolize (convert electrical energy into other forms, such as heat or light). However, it's crucial to note that electricity itself is not alive, but the term "live" is used metaphorically to describe its dynamic and active nature.
Similarly, fire also shares some characteristics with living things. Fire can grow by spreading across available fuel, it metabolizes by consuming fuel and releasing energy in the form of light and heat, and it responds to stimuli such as wind or additional fuel sources. However, fire is a chemical reaction rather than a living organism, as it does not possess cells, genetic material, or the ability to adapt or reproduce.
In summary, understanding the 8 characteristics of living organisms allows us to differentiate them from nonliving things. By comparing examples like rocks and snails, rocks and trees, and dogs and TVs, we can identify the distinctions based on the presence or absence of organization, energy utilization, homeostasis, growth and development, reproduction, response to stimuli, adaptation, and possession of genetic material. Meanwhile, terms like electricity being "live" or the shared characteristics between fire and living things highlight the importance of understanding the specific criteria that define life.