We are all life scientists!

Chapter 1 What is Life?

Key Questions:

What are the Characteristics of Life?

What do living things need to survive?

Chapter 1 What is Life?

What are the Characteristics of Life?

All living things share six characteristics in combination.

These are human cheek cells. What kind of organism are you?

They are made of cells!

•An organism can be made of one single cell – unicellular.

•Or many cells as the building blocks of a larger organism – multicellular.Human cheek cells

400x

Cells are made of other chemicals!

• Proteins

• Carbohydrates

• Lipids

• Nucleic Acids

• Water

• These compounds make up all known life.

Living things respond to surroundings.• Stimulus - a reaction to a change

• Response – an action or behavior

Chapter 1 What is Life?

Living things respond to surroundings.Adaptation - an inherited behavior

or characteristic that enables an organism to survive & reproduce. This type of response takes a long time and many generations.

Over time, adaptations are modified by natural selection.

Chapter 1 What is Life?

Life is always changing…..

On the level of DNA……

Change = Evolution

Living things grow and develop. Grow = largerDevelop = more complex

Living organisms reproduce.

2 types: Sexual reproductionAsexual reproduction

What do living things need to survive?

• Water• Food

Autotroph/heterotroph• Living space• Stable internal

conditions – homeostasis

Test Yourself on these questions…A Short Quiz:

1. What are the six characteristics of life?

2. What is homeostasis? What is an example of homeostasis?3. Is a computer living? Why or why not?

4. Why is energy required by living things?