Characteristics of Life

What makes a living thing “alive”? All living things are made of at least 1 cell. Unicellular = 1 celled (ex. bacteria) Multicelled = many cells (ex. humans)

2) maintain homeostasis. …a stable internal environment. EX: People sweat when they need to cool their bodies.

3) Have genetic material & reproduce ** …DNA is the genetic material. Asexual reproduction = only one organism, offspring are exact replicas of the parent! (ex: binary fission or cloning) Sexual Reproduction = fertilization of egg cell by a sperm cell. Offspring will be a “mixture” of the parents.

4) Have organization …living things are organized at the molecular and cellular level. EX: Humans have many types of systems, organs, tissues & cells.

5) Grow & develop …stages of life and cell division. EX: embryo  adult

6) Need & obtain energy (metabolism) …no energy = dead Organisms can obtain energy in 2 main ways: 1) Autotrophs – make their own food (ex: plants & algae) 2) Heterotrophs – eat another organism (ex: lions & tigers & bears…OH MY!)

Living or Non-Living?

Which characteristic is represented?

Which characteristic is represented?

Which characteristic is represented?

Which characteristic is represented?

Which characteristic is represented?

Other things that living things may also do… Respond to stimuli or environment Communicate Adaptations change over time (evolve)