lesson overview lesson overview studying life 1.3 studying life

Lesson OverviewLesson Overview Studying LifeStudying Life

1.3 1.3 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.”


Characteristics of Living Things

What characteristics do all living things share?


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


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


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


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.


Grow & DevelopAll living things grow at some point.

Some, like bacteria, just grow in size.

Multicellular organisms

go through stages of

development


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.


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


Maintain Internal Balance

Organisms maintain a relatively stable internal environment (internal temperature and water), even when external conditions change dramatically.

Homeostasis:

maintaining

internal balance


Evolve

Over generations, groups of organisms evolve, or change over time.


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.


Organization of Life

• Biosphere

• Ecosystem

• Community

• Population


Biosphere


Ecosystem


Community


Population


Organism


Groups of Cells


Cells


Molecules

lesson overview lesson overview studying life 1.3 studying life

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