Force & Force & Response NotesResponse Notes

TEKS 7.7C demonstrate and illustrate forces that affect motion in everyday life, such as emergence of seedlings, turgor pressure, and geotropism

TEKS 7.13A investigate how organisms respond to external stimuli found in the environment such as phototropism and flight or fight

A A forceforce is a is a push or pull on push or pull on an object in a an object in a

specific specific direction.direction.

Forces can be Forces can be

used by living used by living

organismsorganisms to to

perform basic perform basic

functions.functions.

Forces are used in Forces are used in many ways by many ways by

humanshumans..

For example, For example, interactions between interactions between

the the muscularmuscular & & skeletalskeletal systems allow the body systems allow the body to apply forces needed to apply forces needed

for movement. for movement.

Humans use the force Humans use the force of their of their heartheart muscles muscles

contracting to keep contracting to keep bloodblood flowing through flowing through

their bodies.their bodies.

The The rootsroots of plants of plants use force use force to to pushpush through through the soil.the soil.

Plants use Plants use forceforce in in other ways by other ways by changing their changing their

growth in growth in responseresponse to to their environment. their environment.

These changes These changes are called are called tropismstropisms..

GeotropisGeotropismm occurs occurs when a when a plant plant

grows or grows or bends in bends in response response

to to gravitygravity..

A plant’s A plant’s stem will stem will grow grow upup and its and its

roots will roots will grow grow downdown..

The way a plant The way a plant grows or bends in grows or bends in

response to response to lightlight is is called called

phototropismphototropism..

The plant will grow The plant will grow towardtoward light, even light, even

if it must grow if it must grow sideways.sideways.

When a plant takes When a plant takes in in waterwater, the , the

vacuole exerts vacuole exerts pressure the pressure the

plant’s plant’s cell wallcell wall..

This pressure is This pressure is called called turgor turgor

pressurepressure..

turgor pressure

Turgor pressure Turgor pressure allows a plant to allows a plant to become become rigidrigid causing the causing the plants to stand plants to stand upright.upright.