Notes Ch. 1.2 Life Science Living Things

Living Things Any living thing is called an organism. Living things have specific features they have to have in order to be considered living.

Living Things are Organized All living things are made of cells. A cell is the smallest unit of an organism that carries on the functions of life. Some organisms have only 1 cell (unicellular) while others have many cells (multicellular). All cells have hereditary material (DNA). Hereditary material contains instructions for cellular organization and functions.

Living Things Respond Living things interact with their surroundings. You are affected by everything around you. A stimulus is anything that causes some response in an organism. A reaction is a response. Living things have external (outside) stimuli and internal (inside their bodies/cells) stimuli. Homeostasis is an organism’s ability to keep the right conditions inside no matter what is going on outside the organism.

Living things respond continued Example: If there is a fox chasing a mouse – the fox would be the stimulus for the mouse. The response of the mouse is to run as fast as possible.

Living Things Use Energy Many different processes in an organism require energy. Energy either comes directly or indirectly from the sun. We get energy from the sun by consuming plants. Plants take energy directly from the sun in the process of photosynthesis.

Living Things Grow and Develop All organisms can grow, multicellular organisms gain more cells to grow, while single-cellular organisms grow by increasing the size of the cell. Development is all of the changes that take place during the life of an organism.

Living things grow and develop continued Life span is the length of time an organism is expected to live. Life spans are different for different organisms. Dogs can live for 20 years, cats for 25, mayflies live 1 day, a land tortoise can live for 180 years, humans approximately 85 years.

Living Things Reproduce All organisms need to make more of their own kind. If they did not reproduce that species would die out and no longer exist.

Living things have certain necessities to survive: A place to live: Not many organisms can live in extremely hot or extremely cold environments. All organisms need living space in their surroundings. Example: if a bird population becomes too large there runs out of room to build a nest. Those individuals that cannot build a nest will die off.

Raw materials: Water is important for all living things Raw materials: Water is important for all living things. Other important raw materials are proteins, fats, and sugars. Animals get these raw materials from the food they eat.