Levels of Organization

Atom

Smallest part of matter; contains a nucleus made of protons & neutrons; also contains electrons; nonliving

Molecule

Two or more atoms bonded together; nonliving

Covalent Bond

the sharing of electrons between atoms; forms a bond to create stability and results in the formation of molecules

Ionic Bond

the transfer of electrons between atoms for stability; causes ions to form; it is the positive and negative attraction between the ions that maintains the bond

Octet Rule

a principle in chemistry that displays the need for atoms to have 8 electrons in their outer shell in order to become stable; exception is hydrogen with the need for 2

Macromolecules

large molecules formed by the combination of smaller molecules, essential for biological functions; nonliving; examples includes carbs, proteins, nucleic acids, and lipids

Organelles

parts of a living cell that cannot live on their own; “tiny organs”

Cells

the smallest structural and functional unit of life; they are the basic building blocks of living organisms

Tissues

a group of the same type of cells working together to perform a function; living

Organs

a group of different tissues that work together to perform a specific function in the body; living

Organ Systems

a group of organs that work together to perform complex functions necessary for the survival of an organism; living

Organism

a group of organ systems that work together to maintain life and perform necessary functions for the survival of the organism; living

Population

a group of individuals of the same species living in a specific area, capable of reproduction amongst organisms

Community

a group of different populations that interact with each other in a specific area; consisting of biotic (living) factors only

Ecosystem

a community and their abiotic environment, including factors like soil, water, and climate

Biosphere

the sum of all ecosystems found on Earth, encompassing all living organisms and their environments that can support life