What is life?

What is Life? With your neighbor, make a list of as many living things that you can think of What do they all have in common?

SIX Characteristics of Living Things Cellular organization The chemicals of life Energy use Response to surroundings Growth and development Reproduction

#1 Cellular Organization All organisms are made of cells Cell is basic unit of structure and function in an organism Unicellular – single-celled organism, bacteria Multicellular – many cells that are specialized to do specific tasks

#2 Chemicals of Life Cells are composed of common chemicals: Water – most abundant chemical in the body Carbohydrates – energy Proteins and Lipids - building blocks/energy source Nucleic acids - genetic information/DNA

#3 Energy Use Cells must use energy to carry out their everyday activities Repair injuries, muscles moving, transport The ultimate source of energy is the sun

#4 Response to Surroundings Living organisms respond to stimuli Examples: temperature, light, sound The factor that causes the organism to react is called a stimulus. The reaction an organism has is called the response.

#5 Growth and Development Growth – process of becoming bigger Development – develop change over time (mature)—or get more complex

Organisms get larger by using materials and energy from the environment. Growth occurs through cellular division and cell enlargement.

#6 Reproduction Living organisms can reproduce and produce offspring that are similar to the parents

Life comes from Life Living things arise from living things through reproduction. Hundreds of years ago, people believed in spontaneous generation – the idea that living things could arise from nonliving

Redi’s experiment Italian doctor in the 1600s, Francesco Redi Flies do not spontaneously arise from decaying meat—so life comes from life!

Pasteur’s Experiment French chemist Louis Pasteur, mid 1800s Showed that new bacteria appeared in broth only when they were produced by existing bacteria

The needs of living things Water Food Living Space Homeostasis

All living things need water to survive. Your own body is about 66% water. Water in your blood helps transport food, and chemicals to your cells. Also where chemical reactions in body occur   It helps remove waste products from your body. Water is used to cool you down, to warm you up, and to carry out the chemical reactions that allow you to move and grow.

Organisms use food as their energy source Consumers: Eat other organisms (Heterotrophs)—ex. A lion Producers: Produce own food through photosynthesis (Autotrophs)—ex. A plant   The food organisms take in provides them with energy, and raw materials they need to: build their bodies (tissues) grow repair damage

Habitat A home A place to live where they can find Food, water and shelter

When your body temperature begins to rise, what happens? All organisms need to maintain a stable internal environment called homeostasis. How do living things maintain homeostasis? When your body temperature begins to rise, what happens? You begin to sweat. Sweating is your bodies way of cooling down, and thus maintaining homeostasis

Sugar Levels Blood Pressure