metamorphism is any process that changes a rock's chemical composition.
what is any process that changes a rock's chemical composition?
metamorphism
Na
Na
elemental imbalances arise for a number of physiological and evolutionary reasons related to the differences in the biological make up of organisms, such as differences in types and amounts of macromolecules, organelles, and tissues. organisms differ in the flexibility of their biological make up and therefore in the degree to which organisms can maintain a constant chemical composition in the face of variations in their resources. variations in resources can be related to the types of needed resources, their relative availability in time and space, and how they are acquired. the ability to maintain internal chemical composition despite changes in the chemical composition and availability of resources is referred to as "stoichiometric homeostasis". like the general biological notion of homeostasis, elemental homeostasis refers to the maintenance of elemental composition within some biologically ordered range. photoautotrophic organisms, such as algae and vascular plants, can exhibit a very wide range of physiological plasticity in elemental composition and thus have relatively weak stoichiometric homeostasis. in contrast, other organisms, such as multicellular animals, have close to strict homeostasis and they can be thought of as having distinct chemical composition. for example, carbon to phosphorus ratios in the suspended organic matter in lakes (i.e., algae, bacteria, and detritus) can vary between 100 and 1000 whereas c:p ratios of "daphnia", a crustacean zooplankton, remain nearly constant at 80:1. the general differences in stoichiometric homeostasis between plants and animals can lead to large and variable elemental imbalances between consumers and resources.
ecological stoichiometry