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Lesson OverviewLesson Overview Studying LifeStudying Life
1.3 1.3 Studying LifeStudying Life
Lesson OverviewLesson Overview Studying LifeStudying Life
THINK ABOUT IT
Think about important news stories you’ve heard. Bird flu spreads around the world, killing birds and threatening a human epidemic. Users of certain illegal drugs experience permanent damage to their brains and nervous systems. Reports surface about efforts to clone human cells.
These and many other stories involve biology—the science that employs scientific methodology to study living things. The Greek word bios means “life,” and -logy means “study of.”
Lesson OverviewLesson Overview Studying LifeStudying Life
Characteristics of Living Things
What characteristics do all living things share?
Lesson OverviewLesson Overview Studying LifeStudying Life
Characteristics of Living Things
What characteristics do all living things share?
• Made of Cells• Able to Reproduce• Based on a Genetic Code• Grow & Develop• Need Material & Energy• Respond to the Environment• Maintain Internal Balance• Evolve
Lesson OverviewLesson Overview Studying LifeStudying Life
Made of Cells
Living things are made up of one or more cells—the smallest units considered fully alive.
Despite their small size, cells are complex and highly organized.
• Unicellular Organisms: made of 1 cell• Multicellular Organisms: made of several cells
Lesson OverviewLesson Overview Studying LifeStudying Life
Able to ReproduceLiving things reproduce, which means that they produce new similar organisms. • Asexual Reproduction: one parent divides in two;
results in offspring that are identical to the parent• Sexual Reproduction: involves two parents;
results in offspring that are genetically different than the parents
Lesson OverviewLesson Overview Studying LifeStudying Life
Based on a Genetic Code
All organisms store the complex information they need to live, grow, and reproduce in DNA.
That information is copied and passed from parent to offspring and is almost identical in every organism on Earth.
Lesson OverviewLesson Overview Studying LifeStudying Life
Grow & DevelopAll living things grow at some point.
Some, like bacteria, just grow in size.
Multicellular organisms
go through stages of
development
Lesson OverviewLesson Overview Studying LifeStudying Life
Need Material & Energy
Living things obtain and use material and energy to grow, develop, and reproduce.
The combination of chemical reactions through which an organism builds up or breaks down materials is called metabolism.
Energy can be obtained through photosynthesis or by consuming energy stored by photosynthesis.
Lesson OverviewLesson Overview Studying LifeStudying Life
Respond to the Environment
Organisms detect & respond to stimuli
A stimulus is a signal to which an organism responds.
External Stimuli•light•temperature
Internal Stimuli•blood sugar level•infection
Lesson OverviewLesson Overview Studying LifeStudying Life
Maintain Internal Balance
Organisms maintain a relatively stable internal environment (internal temperature and water), even when external conditions change dramatically.
Homeostasis:
maintaining
internal balance
Lesson OverviewLesson Overview Studying LifeStudying Life
Evolve
Over generations, groups of organisms evolve, or change over time.
Lesson OverviewLesson Overview Studying LifeStudying Life
Interdependence in Nature
All forms of life on Earth are connected into a biosphere, or “living planet.”
Within the biosphere, organisms are linked to one another and to the land, water, and air around them.
Relationships between organisms and their environments depend on the cycling of matter and the flow of energy.
Lesson OverviewLesson Overview Studying LifeStudying Life
Organization of Life
• Biosphere
• Ecosystem
• Community
• Population
Lesson OverviewLesson Overview Studying LifeStudying Life
Biosphere
Lesson OverviewLesson Overview Studying LifeStudying Life
Ecosystem
Lesson OverviewLesson Overview Studying LifeStudying Life
Community
Lesson OverviewLesson Overview Studying LifeStudying Life
Population
Lesson OverviewLesson Overview Studying LifeStudying Life
Organism
Lesson OverviewLesson Overview Studying LifeStudying Life
Groups of Cells
Lesson OverviewLesson Overview Studying LifeStudying Life
Cells
Lesson OverviewLesson Overview Studying LifeStudying Life
Molecules