All living things share the same characteristics:

1. Cells
2. Genetic material
3. Reproduction
4. Metabolism
5. Homeostasis
6. Exchange of gases/wastes with environment
7. Capacity for evolution

Living organisms can be studied based on their cell type, how many cells they are composed of, and how they get food. Below are some examples of how cells can differ:

1. Some cells have cell walls and some only have cell membranes.
2. Some cells have a nucleus and other cells do not. The nucleus houses a cell's genetic material. Some cells have a nucleoid region.
3. Some cells utilize organelles that can harness the sun's energy to make food (photosynthesis); other cells acquire food from their environment (heterotrophs vs. autotrophs).
4. Cell walls can be composed of different substances (usually carbohydrates put together in different ways).
5. Some living organisms are single-celled (bacteria) while others are multicellular.

The most general way to organize living organisms is to divide them into two groups- those composed of cells with a nucleus (eukaryotic cells) and those composed of cells without a nucleus (prokaryotic). YOU are EU-karyotic!

Prokaryotic Cell with Nucleoid Region
Prokaryotic Cell with Nucleoid Region

Plant and Animal Cell
Plant and Animal Cell

Prokaryotic Cell Image Credited to:
Eukaryotic Cell Image Credited to:

All living organisms are classified into one of the following kingdoms:

1. Archaebacteria
2. Eubacteria
3. Protista
4. Fungi
5. Animalia
6. Plantae