| A | B |
|---|
| cell | the building block of all living things |
| tissue | a group of cells that work together to perform a specific job in the body |
| organ | a combination of two or more tissues that work together to perform a specific function in the body |
| 100 trillion | approximately the number of cells in the average human being |
| organ system | a group of organs that works together to perform body functions |
| population | a group of organisms of the same species that live together in the same area at the same time |
| organism | a living thing like plants, fungi, animals, bacteria, etc. |
| unicellular | an organism that is made up of only 1 cell |
| multicellular | an organism that is made up of many cells |
| community | two or more different populations living in the same area (like the flowers, trees, and foxes living in the forest) |
| ecosystem | the living and nonliving things in an area (example: the desert or a pond) |
| terrestrial ecosystems | land ecosystems like a forest or a prairie |
| aquatic ecosystems | water ecosystems like a pond or a river |
| robert hooke | scientist who saw cells for the first time |
| 1665 | date that cells were seen for the first time |
| 1673 | date that unicellular organisms were discovered |
| anton van leeuwenhoek | scientist who discovered unicellular organisms |
| 1838 | date that it was concluded that all plant parts are made of cells |
| 1839 | date that it was concluded that all animals are made of cells |
| cell theory | theory that states that all organisms are made of cells |
| cell membrane | acts as a barrier between the inside of the cell and the cell's environment |
| organelles | structures that enable the cell to live grow & reproduce |
| cytoplasm | fluid filling inside the cell |
| DNA | the hereditary material in the cell |
| prokaryotic cells | cells without a nucleus; bacteria |
| eukaryotic cells | cells with a nucleus |
