Life’s Structure and Classification Section 1: Living Things

A. Organism – any living thing

1. All living things are made of cells, the smallest unit of an organism that carries on the functions of life Plant cell Animal cell

2. All living things grow and develop Growth of a many- celled organism, such as a human, is mostly due to an increase in the number of cells skin cells

b. In a one-celled organism, growth is due to an increase in the size of the cell Amoeba Paramecium

c. All of the changes that take place during the life of an organism are called development Tadpole Polliwog

Frog

3. All living things interact with their surroundings and respond to stimuli. Often, a response results in movement We also call this sensing and responding

4. All living things maintain homeostasis, the regulation of an organism’s internal life- maintaining condition despite changes in its environment

5. All living things use energy 5. All living things use energy. The energy used by most organisms comes either directly…

…or indirectly from the Sun

6. Living things reproduce to make more of their own kind 6. Living things reproduce to make more of their own kind. Otherwise, they would die out.

B. Living things need a place to live, food, and water