Characteristics of Life Ch.1 Sec.4

Intro to the Characteristics of Life Video Clip

What is Biology? • Biology – the study of life

• One person cannot study all the areas of biology; therefore, scientists specialize.

• Biochemistry

• Evolutionary Theory

• Ecology

• Microbiology

• Cell Biology

• Botany

• Genetics

• Zoology

• Anatomy &

Physiology

What are the characteristics of life?

Made of Cells • What is a cell?

▫ Smallest unit of life

▫ Every cell exhibits ALL the characteristics of life

▫ Very organized and complex

= one cell • Unicellular

= many cells • Multicellular

Reproduction

• Reproduction – the production of new cells or organisms

• Cells divide to form new cells

Heredity • Heredity – the passing

of traits from parent cells to offspring cells.

• DNA – genetic material

▫ Stands for deoxyribonucleic acid

Growth

• Growth – increasing in size or mass

▫ All organisms have a life cycle or pattern of growth throughout their lifetime

Growth • Development – when an organism’s cells divide

and differentiate (specialize)

Metabolism

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

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

Responsiveness

• An organism’s ability to detect and respond to an environmental stimulus.

• Day to night, temperature change, predators

Responsiveness Examples

Homeostasis • Homeostasis – the process of

maintaining a constant internal environment

▫ What needs to be maintained?

Temperature, pH, salt concentration

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

• If homeostasis is disrupted, the organism cannot survive.