What is Biology? • Biology – the study of life

• One person cannot study all the areas of

biology; therefore, scientists specialize.

– What does specialize mean?

•Biochemistry

•Evolutionary Theory

•Ecology

•Microbiology

•Cell Biology

• Botany

• Genetics

• Zoology

• Physiology

• Anatomy

Chapter 1 Section 4 What is biology?

What are the

characteristics of life?

Cellular Organization

• Made up of cells

• What is a cell?

– Smallest unit of life

– Every cell exhibits ALL the characteristics of life

– Very organized and complex

• Unicellular

• Multicellular

= one cell

= many cells

Reproduction

• Reproduction – the production of new

organisms/cells

• Cells divide to form new cells

Heredity

• DNA – genetic material

– Stands for deoxyribonucleic acid

• Traits are passed from parent cells to offspring

cells.

Growth

• Every organism has a life cycle or

pattern of growth throughout its

lifetime

– E. coli (bacteria) begins growing in size

until it divides (asexual reproduction) to

form two identical cells.

Growth

• Some multicellular organism’s life

cycles include development

– Egg larva (caterpillar) pupa

(cocoon) adult (butterfly)

– Cell number increases and the cell

differentiate (or specialize)

Metabolism

• Energy and materials are needed to grow, develop, and reproduce

• Metabolism – a combination of chemical reactions that occur in the cells that build up or break down materials to sustain life

Responsiveness • Environments are constantly changing

– Day to night, summer to fall

• Organisms must respond to these

changes to survive

Homeostasis • Homeostasis – the process of

maintaining a constant internal environment

– Temperature, pH, salt concentration, etc. must be maintained.

• Organisms must respond to changes in the external environment by controlling the internal environment.

• If homeostasis is disrupted, the organism cannot survive.

What are the

characteristics of life?

Characteristics of Life

• Made of Cells

• Reproduction

• Heredity

• Growth

• Metabolism

• Homeostasis

• Responsiveness