Characteristics of Life

What is Biology? Biology is the study of living things Some branches of biology include biochecmistry ecology, cell biology, genetics, evolutionary theory, microbiology botany, zoology, and physiology What is a living things? All living things share several properties.

1.Cellular Organization All living things are made up of cells Cell-the smallest unit of living matter that is enclosed by cell membrane that separates it from its surroundings Unicellular- describes living things made up of only 1 cell Multicellular-describes living things made up of many cells

2. Homeostasis All living things maintain an internal balance Homeostasis-process by which organisms keep their internal conditions relatively stable. An organism’s homeostasis is threatened by changes in its environment Examples of how organisms maintain homeostasis: Sweating Shivering Physical movement

3. Metabolism Living things carry out many chemical reactions in order to obtain energy Organisms need materials and energy to grow, develop, reproduce, and stay alive. Metabolism-the combination of chemical reactions in which an organism builds up or breaks down materials as it carries out its life processes.

4. Responsiveness Living things respond to their environment Stimulus- any change in an organism’s environment Response- an organism’s reaction to a particular stimulus Examples: Flower bends toward light Bird fluffs feathers when cold

5. Reproduction Process by which organisms make more of their own kind from one generation to the next Sexual Reproduction- two cells from different parents unite to produce a new organism. Asexual Reproduction- a single parent reproduces to form a new organism

6. Heredity Process of organism passing on its own traits to its offspring Life is based on a universal genetic code- the genetic code of DNA determines the inherited traits of every living organism on Earth (with only minor exceptions.)

7. Grow and Develop Growth- an increase in cell size and number Development- a change that occurs in an organism Examples: Caterpillar Tadpole

Evolution Evolution-change over time When a new species develops from preexisting species over time. A group of living things can evolve or change over time The ability of a group to change over time is invaluable for survival in a world that is always changing.