What does it mean to be alive?
Characteristics of Living Things
- M = movement (yes, even plants can move their leaves towards the sunlight!)
- R = respiration (process of releasing energy from food, usually requires oxygen)
- S = stimuli (reacts to its environment)
- G = grows and develops; made of one or more cells that grow and divide; some cells specialize (ex. skin cells, heart cells)
- R = reproduction (makes new organisms of the same species)
- E = Elimination of wastes (gases (O2, CO2), water, solids (poop!)
- N = nutrition, requires energy [makes (producer) or acquires (consumer) food]
- C = Living things are made of cells
Not all living things show all of these characteristics all of the time.......
but all living things have all these characteristics at some point in their life cycle
but all living things have all these characteristics at some point in their life cycle
So, while fire and clouds can move and grow, they do not have ALL the characteristics listed above. In particular, they are not made of cells. Interestingly, bone, shells and feathers may be made BY a living thing, however, the bones, shells and feathers themselves are abiotic because they are not made of cells. Fossils of bones are also abiotic as the bones or shells are replaced over time by minerals, which are abiotic. So in the case of fossilized bones, neither the bone or the fossil are biotic, even though the bones were made by the living organism.
When we ask whether an organism that has feathers or bones or shells is biotic, we say that it is, because the entire organism is largely made of cells that cooperate to function as a living thing.
When we ask whether an organism that has feathers or bones or shells is biotic, we say that it is, because the entire organism is largely made of cells that cooperate to function as a living thing.