1. SCIENCE

2. 1-1 What is Science?
Humans have a great capacity for wonderment and problem-solving.
Our brains look for patterns and make connections
Humans have been around for about 200,000 years.
Humans have only been using the scientific method for about 400 years.

3. Simple Timeline of Great Thinkers
400 BC Ancient Greeks Aristotle & Democritus
Conclusions based on logic and untested observations
1300s Monks and Theologians
Started to think about proper methods of science
1600s Microscope & Telescope invented
1637 First Scientific Method
Making conclusions by testing observations

4. The goal of science is to:
investigate and understand the natural world.
explain events in the natural world.
use those explanations to make useful predictions.
Science is:
an organized way of using evidence to learn about the natural world.
The Scientific method is:
A way to ask and answer questions about the natural world by first observing, then TESTING, then making conclusions.

5. The Scientific Method

6. The Scientific Method
Observations: process of gathering information in an orderly way
Data: the information gathered
Qualitative: descriptive information without measurements
Quantitative: measured information expressed as numbers
Inference: a logical interpretation based on prior knowledge or experience

7. The Scientific Method
Hypothesis: a proposed scientific explanation for a set of observations; based on prior knowledge
Often called “an educated guess”
MUST be able to be tested by experimentation!
Conclusion: results or answers based on experiments.
Peer review helps ensure that conclusions are valid.

8. 1-2 How Do Scientists Work?
Asking a Question
Many years ago, people asked: How do organisms come into being?
Forming a Hypothesis
One early hypothesis was spontaneous generation, : the idea that life could come from nonliving matter.
People thought that maggots spontaneously appeared on meat.
In 1668, Redi proposed a new hypothesis: maggots come from eggs that flies laid on meat.

9. How do scientists test hypotheses?
Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time.
All other variables should be kept unchanged, or controlled.

10. Setting Up a Controlled Experiment
There are 3 types of variables:
Controlled: things that stay the same ex:
Manipulated: variable you deliberately change ex:
3. Responding: variable that changes in response to the manipulated variable (the thing you changed)

11. Redi’s Experiment

12. Redi’s Experiment

13. Repeating Investigations
Needham's Test of Redi's Findings
Needham challenged Redi’s results by claiming that spontaneous generation could occur under the right conditions.
He sealed a flask of gravy & heated it.
After several days the gravy had microorganisms.

14. Repeating Investigations
Spallanzani’s Test of Redi's Findings
Two flasks of gravy were boiled.
One was sealed & one left open.
The open flask grew microorganisms.

15. Repeating Investigations: Pasteur’s Experiment

16. Pasteur's Test of Spontaneous Generation
Louis Pasteur conclusively disproved the hypothesis of spontaneous generation.
Pasteur showed that all living things come from other living things.

17. How a theory develops
As evidence from numerous investigations builds up, a hypothesis may become so well supported that scientists consider it a theory.
A theory is a well-tested explanation that pulls together a broad range of observations.
Theories are revised as new evidence is uncovered

18. 1-3 Studying Life The Characteristics of Living Things
Are made up of cells
A cell is the smallest unit of an organism that can be considered alive
Reproduce
Sexual reproduction: cells from two different parents unite to form the first cell of the new organism
Asexual reproduction: a single parent produces offspring that are identical to itself

19. The Characteristics of Living Things
Are based on a universal genetic code
Organisms store the information they need to live, grow, and reproduce in a genetic code in a molecule called DNA. (deoxyribonucleic acid)
Grow and develop
Its cells differentiate: they look different and perform different functions
UNICELLULAR – increase in size
MULTICELLULAR – increase in size & number of cells

20. The Characteristics of Living Things
Obtain and use materials and energy
Ex: food, water, minerals
The combination of chemical reactions through which an organism builds up or breaks down materials is called metabolism.
Respond to their environment
A stimulus is a signal to which an organism responds. It is what causes a response.
Ex: light, temperature, noise
A response is the reaction.

21. The Characteristics of Living Things
Maintain a stable internal environment
Although conditions outside an organism may change, conditions inside an organism tend to remain constant.
This process is called homeostasis.
Ex: internal temp. of 98.6 – regulate by sweating or goose bumps
Fluids- too little(dehydrate), too much (cells swell)
Birds puff up feathers to stay warm
Evolve – over time and many generations

22. How can life be studied at different levels?