Levels of Organization (bio - unit 2)

atom

the ____ is the smallest unit of matter. nonliving

molecule

____s are many atoms bonded together. nonliving

organelle

_____s are formed by multiple types of biomolecules bonding together to create a microscopic structure. nonliving

cell

____s are the smallest unit of life. living

tissue

____ is made of multiple cells with the same functions working together as a whole. living

organ

____s are multiple tissue layers and cells working together as a complete structure. living

organ system

____ ____s are a collection of organs, tissues and cells working together to maintain specific life functions. living

organism

____s are comprised of various body systems, organs, tissue and cells cooperatively working together. living

population

a ____ is a group of organisms making up the same species. living (think location and time)

community

a _____ is a cluster of multiple species living and interacting in a small local area. living

ecosystem

____s are made up of large populations of species living, interacting and inhabiting a large area. living (+ nonliving environment)

biome + biosphere

a ____ is made up of multiple ecosystems. ____  is where life is found on Earth.  living

examples: atoms

C H N O P S

examples: molecules

C\6H\12O\6
CO\2
O\2

examples: organelles

mitochondria, lysosomes, chloroplasts

examples: cells

euglena, helophile, neuron, muscle cell

examples: tissues

cardiac ____, muscular ____, epithelial ____, nervous tissue

examples: organs

heart, arteries, veins, capillaries, lungs

examples: organ systems

skeletal ____, muscular ____, cardiovascular ____, respriatory ____

examples: organisms

humans, grolar bear, e. coli, amoeba, yeast, oak tree

examples: populations

human population on mcdonogh’s campus in 2026

examples: communities

within an oak tree: robin, caterpillar, squirrel, child

examples: ecosystems

within a pond: deer, birds, fish

examples: biomes

tundra, tropical, rainforest, desert