Organization of Life
Levels of Organization
• The different branches of biology can be classified based on different levels of complexity
• Each “level” is made up of smaller component, and usually contributes to a larger system.
Levels- smallest to biggest
1. Molecules- groups of atoms; the smallest unit of most chemical compounds
2. Cells- smallest functional unit of life. Basic units of structure and function.
3. Tissues- composed of specialized cells which perform a specific function– Ex. Blood, muscle, nerve
Levels of Structural Organization
Figure 1.1, step 1
Molecules
Atoms
Chemical levelAtoms combine toform molecules
Levels of Structural Organization
Figure 1.1, step 2
Smooth muscle cellMolecules
AtomsCellular levelCells are made up of molecules
Chemical levelAtoms combine toform molecules
Levels of Structural Organization
Figure 1.1, step 3
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Cellular levelCells are made up of molecules
Tissue levelTissues consist ofsimilar types of cells
Chemical levelAtoms combine toform molecules
Levels- smallest to biggest
4. Organs- groups of specialized tissues that perform a specific function
– Ex. Heart, brain, liver, skin
5. Organ Systems- consist of different organs that work together to perform a specific function
– Ex. Digestive, nervous
6. Organism- any single living thing
Levels of Structural Organization
Figure 1.1, step 4
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Epithelialtissue
Smoothmuscletissue
Connectivetissue
Bloodvessel(organ)
Cellular levelCells are made up of molecules
Tissue levelTissues consist ofsimilar types of cells
Organ levelOrgans are made upof different typesof tissues
Chemical levelAtoms combine toform molecules
Levels of Structural Organization
Figure 1.1, step 5
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Epithelialtissue
Smoothmuscletissue
Connectivetissue
Bloodvessel(organ)
Cardio-vascularsystem
Cellular levelCells are made up of molecules
Tissue levelTissues consist ofsimilar types of cells
Organ levelOrgans are made upof different typesof tissues
Organ system levelOrgan systems consist of differentorgans that work together closely
Chemical levelAtoms combine toform molecules
Levels of Structural Organization
Figure 1.1, step 6
Smooth muscle cellMolecules
Atoms
Smoothmuscletissue
Epithelialtissue
Smoothmuscletissue
Connectivetissue
Bloodvessel(organ)
Cardio-vascularsystem
Cellular levelCells are made up of molecules
Tissue levelTissues consist ofsimilar types of cells
Organ levelOrgans are made upof different typesof tissues
Organ system levelOrgan systems consist of differentorgans that work together closely
Organismal levelHuman organismsare made up of manyorgan systems
Chemical levelAtoms combine toform molecules
Getting Bigger…• Population: Organisms of a species interact to
form a population– Species: group of similar organisms that are capable
of interbreeding to produce fertile offspring.
• Community: Populations of different species that live together in an area create a community.
• Ecosystem: The community and it’s non-living environment make up an ecosystem.
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