Unit 1: Introduction to Biology & the Scientific Method 🔬🧬
What Is Biology?
Biology is the study of life. It examines:
● Living organisms
● How organisms function
● How organisms interact
● How organisms change over time
The word comes from:
● Bio = life
● Logy = study of
Biology covers everything from microscopic bacteria to giant ecosystems.
Major Branches of Biology
Branch Study
Zoology Animals
Botany Plants
Microbiology Microscopic organisms
Genetics Heredity and DNA
Ecology Interactions with environment
Anatomy Body structure
Physiology Body functions
Evolutionary Biology How species change over time
,Characteristics of Life 🧫
Scientists use specific characteristics to determine whether something is living.
1. Made of Cells
All living things are composed of one or more cells.
Examples:
● Bacteria = one cell
● Humans = trillions of cells
Cells are the basic unit of life.
2. Use Energy (Metabolism)
Living things need energy to survive.
Examples:
● Plants use sunlight
● Animals eat food
Metabolism includes:
● Breaking down food
● Producing energy
● Building molecules
3. Grow and Develop
Living organisms increase in size and change over time.
Growth
Increase in size or number of cells.
Development
, Changes in form/function over life.
Example:
Seed → plant
Baby → adult
4. Reproduce
Living things create offspring.
Sexual Reproduction
Two parents.
Asexual Reproduction
One parent.
Purpose:
Pass DNA to the next generation.
5. Respond to Stimuli
A stimulus is a change in the environment.
Examples:
● Pulling hand from hot stove
● Plant bending toward light
● Shivering in cold weather
6. Maintain Homeostasis ⚖️
Homeostasis = maintaining stable internal conditions.
Examples:
● Sweating when hot
What Is Biology?
Biology is the study of life. It examines:
● Living organisms
● How organisms function
● How organisms interact
● How organisms change over time
The word comes from:
● Bio = life
● Logy = study of
Biology covers everything from microscopic bacteria to giant ecosystems.
Major Branches of Biology
Branch Study
Zoology Animals
Botany Plants
Microbiology Microscopic organisms
Genetics Heredity and DNA
Ecology Interactions with environment
Anatomy Body structure
Physiology Body functions
Evolutionary Biology How species change over time
,Characteristics of Life 🧫
Scientists use specific characteristics to determine whether something is living.
1. Made of Cells
All living things are composed of one or more cells.
Examples:
● Bacteria = one cell
● Humans = trillions of cells
Cells are the basic unit of life.
2. Use Energy (Metabolism)
Living things need energy to survive.
Examples:
● Plants use sunlight
● Animals eat food
Metabolism includes:
● Breaking down food
● Producing energy
● Building molecules
3. Grow and Develop
Living organisms increase in size and change over time.
Growth
Increase in size or number of cells.
Development
, Changes in form/function over life.
Example:
Seed → plant
Baby → adult
4. Reproduce
Living things create offspring.
Sexual Reproduction
Two parents.
Asexual Reproduction
One parent.
Purpose:
Pass DNA to the next generation.
5. Respond to Stimuli
A stimulus is a change in the environment.
Examples:
● Pulling hand from hot stove
● Plant bending toward light
● Shivering in cold weather
6. Maintain Homeostasis ⚖️
Homeostasis = maintaining stable internal conditions.
Examples:
● Sweating when hot
