1. What is Science?
A way of learning and thinking about the natural world using experimentation to make conclusions
Scientists collect information, look for patterns and connections, and propose explanations
Science is always changing with new observations, tests, equipment, viewpoints, and discoveries that lead to new theories and revising old ones
Important to YOUR life
Should the government have your DNA? Does a person begin at conception? Did we evolve?

2. How Science Works Observation
Being with an observation using the senses
Gather information from observations called data
Data can be quantitative or qualitative
Make logical inferences using data
Ex- If 100 samples from the lake contain algae, then all the water contains algae

3. How Science Works Hypothesis
After the observation, scientists ask a question about what they noticed
This leads to forming a hypothesis or an educated guess for a set of observations
“If… then…” statement- If fertilizer is added to a plant, then it will grow faster.
Uses prior knowledge, logical inferences, and informed imagination

4. How Science Works Experiment
The hypothesis is tested in a controlled experiment where only 1 variable is tested
Control- group in which all conditions are kept the same
Variable- all conditions kept the same except for the single condition being tested for
Independent Variable (IV)- changed on purpose, manipulated, what “I” do/change
Dependent Variable (DV)- changes according to the IV, depends on the IV, what you measure

5. How Science Works Results
Data is measured and recorded from the experiment
Charts and tables are created of the data
Data is also analyzed to see if hypothesis was correct or not

6. How Science Works Conclusion
The results are explained and the hypothesis is shown as true or false
Any errors and limitations in the experiment are discussed
If the hypothesis was shown false, it will be tweaked and another experiment will be performed

7. How Science Works Other Issues
Controlled experiments are not always possible in the lab, for ethical reasons or if there is a large sample size
Hypothesis – Theory - Law

8. Experiment Example Observations- plants die in the dark
Q- Does the color of light affect plant growth?
Hypothesis- If plants are under colored lights, then they will not grow as fast as under white lights
Experiment- Set up 5 plants in separate closets with red bulbs and one with white. Measure grow in cm for 10 days. All plants receive same amount of water, soil, etc.

9. Experiment Example Control- Plant under white light (no “treatment”)
IV- plants with colored lights (manipulation, I changed)
DV- growth of the plants with colored lights (depends on…. Color)
Results- All 5 plants died, and the one with white light grew 4 cm
Conclusion- Hypothesis correct…. What does this mean?

11. Real Example
In the 1600s, the main hypothesis for how life starts was that it starts from abiotic matter
This was called spontaneous generation or abiogensis
In 1668, Francesco Redi proposed that life came from life, called biogenesis
Observation- Flied land on meat uncovered and maggots appear

12. Hypothesis- Flies produce maggots

13. Real Example
In the 1800s, scientists continued to argue over abiogensis
In 1864, Louis Pasteur’s experiment finally proved biogensis using broth and S-shaped flasks and observing bacterial growht
Bacteria would only grow if the flask was normal and exposed to air
Flasks with S-shape would not allow growth

15. Biology Study of life Organism- any living thing
Species- organisms that can produce offspring that can breed

16. Characteristics of Life
Made up of cells
-Cells are the smallest unit of life
-Organisms can be made of one cell, called unicellular
-Organisms can be made of many cells, called multicellular

17. Characteristics of Life
2. Reproduce-
Sexually involves sex cells from two parents fusing to make the first cell of a new organism
Asexually involves one parent using itself to create a new organism

18. Characteristics of Life
3. DNA- living things are made up of the genetic code DNA
DNA acts as a blueprint that directs the growth and development of an organism
DNA also dictates that organisms will only reproduce their own kind

19. Characteristics of Life
4. Grow and Develop
They go through specific life stages from young to adult to old
5. Energy
Energy is obtained in photosynthesis from the sun for plants, and in food for animals
6. Respond
Stimulus- a signal to which an organisms responds
External- come from the environment
Internal- come from within the organism

20. Characteristics of Life
7. Homeostasis- Living things must maintain a stable internal environment despite changes
8. Evolve/Adapt- As a group living things must be able to adapt over time, or evolve
Desert plants have thicker “skin”
The greater the diversity within a species, the greater chance of surviving environmental changes

21. Levels of Organization
Biosphere- all of earth’s ecosystems
Ecosystem- communities and their abiotic surroundings
Community- populations that live together in a defined area
Population- group of the same organisms that live in a defined area
Organism- one individual living thing

23. Levels of Organization
Organ System- a group of organs working together, like the digestive system
Organ- a group of tissues working together, like the heart
Tissue- a group of cells working together, like muscle tissue
Cell- the smallest functional unit of lie, like a muscle cell
Molecules- groups of atoms that form chemicals like water and DNA. NOT alive

24. Tools Light Microscope Transmission electron microscope
Light passes through lenses to magnify a specimen
Transmission electron microscope
A beam of electrons reveals the inside of a specimen up to 100,000x
Scanning electron microscope
A beam of electrons scans the outside of specimens up to 10,000x