• Defined: the study of life• Organism: anything that can

carry on the processes of life• Species: organisms that can

create fertile offspring– Over 2 million known

species– More diverse along

equator• Oldest life (bacteria) = 3.5

billion years old

Biology

1) Made of cells

2) Reproduces

3) Grows and Develops

4) Has organization

5) Requires energy

6) Responds to environment

1) Made of cells

2) Reproduces

3) Grows and Develops

4) Has organization

5) Requires energy

6) Responds to environment

• All life (from bacteria to humans) has a few common characteristics

1) Based from cells– Cell = most basic unit of life– All cells capable of carrying on life processes– Some cells specialized for specific duties

• Ex: Red blood cells carry O2

Life Characteristics

2) Requires energy– Energy = ability to do work or cause change– Energy controls metabolism (ability to break down

materials)– Most life energy obtained from the sun

• Autotrophs: create energy from the sun (ex: plants & algae)

• Heterotrophs: consumer others for energy (ex: fungi & animals)

Life Characteristics

3) Responds to environment– Stimulus =

environmental factors

– ex: Sound, light, touch

Life Characteristics!*%!?%&#

• 4) Reproduces and develops– Genetic material (DNA/RNA)

passed to next generation– Asexual reproduction:

offspring produced from a single parent

• Offspring genetically identical to parent

– Sexual reproduction: offspring is a genetic mixture of two parents

• More diversity

Life Characteristics

00.20.40.60.8

11.21.4

Heig ht (meters )

with large trees without large trees

P lant G rowth

What is science?• Science is a way of thinking, questioning,

and gathering evidence.– Scientific method

• Defined: Series of steps to collect information or solve problems

1) Observation

2) Hypothesis

3) Experimentation

4) Data Analysis

5) Conclusion

Scientific Method

Observation and Hypothesis• 1st step: Make an

observation– Example: Why is there little

ground vegetation in this forest?

• 2nd step: Create a hypothesis– If…then statement– Example: If there are tall

trees blocking sunlight, then few plants will grow near the ground.

3rd step: Design an Experiment

• Experiments test the independent variable

• Independent variable: factor altered

• Two parts to an experiment1) Control group: comparison group

• Ex: patch of forest with the large trees

• 2) Experimental group: contains the independent variable• Ex: patch of land w/o

canopy trees• Data collected is called

the dependent variable• Ex: growth height of

the plants

Here is a well designed setup

Control Group Experimental Group

•6 hours sun/day •6 hours sun/day•8cm rain/month •8cm rain/month

•Grazing animals•Grazing animals

•60⁰ temp •60⁰ temp

•Large canopy trees •Patch of open land

The experimental plants grew 1 meter taller. What most likely caused this change?

Here is a poorly designed setup

Control Group Experimental Group

•6 hours sun/day•4 hours sun/day

•8cm rain/month •8cm rain/month

•Grazing animals•Grazing animals

•60⁰ temp •80⁰ temp

•Large canopy trees •Patch of open land

The experimental plants grew 1 meter taller. What most likely caused this change?

•Unknown! Too many changed variables!

4th Step: Data Analysis

• Collect data to either support/reject your hypothesis– Ex: Plants on the ground grew almost 1m taller w/o

the canopy trees– No hypothesis is proven after 1 experiment

00.20.40.60.8

11.21.4

Heig ht (meters )

with large trees without large trees

P lant G rowth

5th Step: Conclusion• Your findings could be

shared and repeated by others

• Theory develops over time– Theory = long standing

hypothesis

• Theories and hypotheses change based on new information

Farmer Bob wants to test his new fertilizer to help his crops grow better. He sections off two large areas of his field. In section A, he waters his crops as usual but adds no fertilizer. In section B, he waters his crops as usual and also adds his experimental fertilizer. After 1 growing season, he records the growth of the crops.

Name the control group _________________________________________________

Name the experimental group ____________________________________________

Name the independent variable __________________________________________

Name the dependent variable ____________________________________________

Section A

Section BSubstance added to the crops

Growth of the crops

The United States military wants to see if soldiers with only 4 hours of sleep can operate at the same level as those who normally get 7 hours of sleep. One hundred solders are allowed to only sleep for 4 hours a night and another hundred are allowed to sleep for 7 hours a night. During the day, the soldiers are tested for marksmanship on the firing range.

Name the control group _________________________________________________

Name the experimental group ____________________________________________

Name the independent variable __________________________________________

Name the dependent variable ____________________________________________

Soldiers with 7 hours sleep

Soldiers with 4 hours sleepAmount of sleep given

Score on the firing range

Example• Smithers thinks that a special juice will

increase the productivity of workers. • He creates two groups of 50 workers

each and assigns each group the same task (in this case, they're supposed to staple a set of papers). – Group A is given the special juice to drink

while they work. – Group B is not given the special juice.

• After an hour, Smithers counts how many stacks of papers each group has made. – Group A made 1,587 stacks– Group B made 2,113 stacks.

•Identify the: 1.Control Group

•2. Independent Variable

•3. Dependent Variable

•4. What should Smithers' conclusion be?

A teacher wants to know if her new teaching method is more successful than traditional teaching methods. She compares test scores of her period 2 class (received the traditional teaching method) verses her period 4 class (received new teaching method). Each class has a random mix of honors students.

Name the control group _________________________________________________

Name the experimental group ____________________________________________

Name the independent variable __________________________________________

Name the dependent variable ____________________________________________

Period 2 students

Period 4 studentsTeaching method

Test scores

A high school soccer team on average scores 2.2 goals per game by practicing 4 days a week. The coach wants to see if practicing 5 days a week will help the team score more goals. The coach has the team practice 5 days per week and compares the goals scored per game.

Name the control group _________________________________________________

Name the experimental group ____________________________________________

Name the independent variable __________________________________________

Name the dependent variable ____________________________________________

Practicing 4 days per week

Practicing 5 days per weekLength of practice

Goals scored per game

The city of Los Angeles wants to know if there is a connection between physical fitness and air pollution. Fifty volunteers from the mayor’s office agree to be tested. First, they are asked to ride a stationary bike for 1 hour in a pollution-free air chamber. A week later, the 50 volunteers return and are again asked to ride a stationary bike for 1 hour in a chamber filled with air pollutants common to Los Angeles. Their heart rates are monitored throughout the 1 hour bike rides.

Name the control group _________________________________________________

Name the experimental group ____________________________________________

Name the independent variable __________________________________________

Name the dependent variable ____________________________________________

Volunteers who breathed common polluted air

Volunteers who breathed clean airQuality of air breathed

Heart rates