Characteristics of Life

Biology• = study of living things

• There is great diversity among living things

• All living things share certain characteristics

Cells• All living things are made of cells

• Cell = smallest unit of structure and function for living things

• Some organisms are– Unicellular = made up of one cell– Multicellular = made up of many cells

Reproduction• All living things are able to produce

offspring

• Through this process, living things pass on their genetic traits

Genetic Code• All living things have a universal genetic

code

• The genetic code is based on DNA and its four nitrogen bases – A, T, C, and G

Growth / Development• All living things grow / develop at some

point during their lifetime.

• Growth = increase in size; usually occurs through mitosis (cell division)

• Development = changes; for instance, specialization of certain structures for certain jobs in an organism’s body

Metabolism• All living things must obtain and use

energy

• Metabolism = all of the reactions in an organism– Photosynthesis = process plants use to get

energy from the sun– Cellular respiration = process used to break

down food energy into cell energy (ATP)

Respond to Environment• All living things are able to respond to

things happening in and around them (stimuli)

– Plants grow toward sunlight– People shiver when they are cold

Homeostasis• All living things try to maintain a stable

internal environment

– Resting heart rate = 72-76 beats per minute– Resting breathing rate = approx. 15 breaths

per minute– Normal body temperature = 98.6 oF (37 oC)

Evolution• = change in a species over time

• All living things, as a group, change over time– Populations evolve

• Population = members of the same species living in the same place at the same time

– Individuals do NOT evolve