Physically Break Down Non-living Materials
Nonliving materials are not carbon-based; that is, they are not and never have been living organs or tissues. However, they can be the products of living organisms, such as the calcium carbonate materials found in seashells (excluding organic compounds included in them). Physically breaking down nonliving materials requires mechanical means. While feeding, some living systems encounter very hard nonliving materials that can hinder access to the food. To address this, their teeth or other structures often contain minerals to maximize their hardness. For example, a marine organism called the chiton eats algae. But to access the algae, it must scrape it from rocks. To do so, it uses a special structure made of a material that’s stronger than the rock.
Modify Material Characteristics
The materials found in living systems are variable, yet often made from the same basic building blocks. For example, all insect exoskeletons consist of a material called chitin. Because material resources are limited, each material within or used by a given living system must frequently serve multiple purposes. Therefore, living systems have strategies to modify materials’ softness, flexibility, and other characteristics. To ensure survival, the benefits of these modifications must outweigh the living system’s energy and material expenditure to generate them. For example, spiders store the liquid components of spider silk in a gland, converting them into silk thread when needed. Some threads have different characteristics, such as elasticity and UV reflectance, than others.
