1. Introduction to Biology Chapter #1

2. Characteristics of Life
Chapter 1.1

3. What is an organism?
Organism= anything that has or once had all of the characteristics which define life

4. Characteristics of Life #1: Made of One or More Cells
Unicellular= organisms consisting of a single cell
Examples: Prokaryotes (eubacteria & archaebacteria), protists & fungi

5. Characteristics of Life #1: Made of One or More Cells
Multicellular = organisms that consist of more than one cell
Examples: animals, plants & fungi
Which group of organisms can be either multicellular OR unicellular???

6. Characteristics of Life #2: Displays Organization
Organization = living things are arranged in an orderly way
Each organized structure in an organism has a specific function:
E.g. – an anteater’s snout holds the anteater’s long tongue

7. Characteristics of Life #2: Displays Organization
The levels of biological organization from smallest to largest are:
Atom < Molecule < Cell < Tissue < Organ < Organ System < Organism

8. Characteristics of Life #3: Grows and Develops
Most organisms begin as one cell!
Growth = results in the addition of mass to an organism, and in many organisms, the formation of new cells and new structures

9. Characteristic of Life #3: Grows and Develops
Development = the process of natural changes that take place during the life of an organism

10. Characteristics of Life #4: Reproduces
Reproduction = the production of offspring
Not an ESSENTIAL characteristic of living organisms
Can you think of any situations in which a living organism would be incapable of reproducing?
Asexual vs. sexual reproduction

11. Characteristics of Life #4: Reproduces
Species = a group of organisms that can breed with one another and produce fertile offspring
What happens when reproductive barriers between different species are not complete?
Hybrids = offspring of two different species which interbreed
When the reproductive barriers between two species are incomplete, the species must be closely related
Horse + Donkey = Mule
Mules are sterile
Dog + Wolf = Dog-wolf hybrid
Hybrid is fertile

12. Characteristics of Life #5: Responds to Stimuli
Organism’s Internal Environment = all things inside of an organism
Organism’s External Environment = all things surrounding an organism
E.g. air, water, soil, rocks, and other organisms

13. Characteristics of Life #5: Responds to Stimuli
Stimulus = anything that is part of either an organism’s external or an organism’s internal environment that causes a reaction
Response = an organism’s reaction to a stimulus

14. Characteristics of Life #6: Requires Energy
Autotrophs = organisms that produce their own energy using light from the sun through photosynthesis.
Heterotrophs = organisms that get their energy requirements by consuming other organisms

15. Characteristics of Life #7: Maintains Homeostasis
Homeostasis = regulation of an organism’s internal conditions to maintain life
Athletes at high altitudes
Produce more red blood cells to carry oxygen to the tissues

16. Characteristics of Life #8: Adaptations Evolve Over Time
Adaptation = any inherited characteristic that results from changes in a species over time
The “Aye-Aye”

17. Characteristic of Life #9: Has a Genetic Code
All organisms store the complex information they need to live, grow, and reproduce in a genetic code written in a molecule called DNA.
What percentage of human DNA is shared with chimpanzees???

18. Which 2 characteristics of life is this list missing???

19. What is Science?
Chapter 1.2

20. Definition of Science
Science = an organized way of using evidence to learn about the natural world
AND
Science = the body of knowledge scientists have built up over the years using this process

21. What is Science??? Relies on evidence Expands scientific knowledge
Challenges accepted theories
Questions results
Tests claims
Undergoes peer review
Peer review = a process by which the procedures used during an experiment and the results are evaluated by other scientists.
7. Uses the metric system (Meter, gram, liter, second)

22. Science is Always Changing: An Example from Astronomy
Name that HOTTIE!

23. Copernicus and his heliocentric model
Old Geocentric Model
New Heliocentric Model

24. Science and Human Values
We use science to inform decisions about health care, environmental policy, etc.
Many of science’s major discoveries have been considered controversial b/c they call into question certain beliefs (ethics)
Example: Cloning, stem cell research, evolution

25. The Scientific Method
Chapter 1.3

26. Scientists make Observations
What observations can you make about this image???

27. Observations vs. Inferences
Observation = a direct method of gathering information in an orderly way
Recording information from the five senses
Inference = combining what you know with what you have learned and beginning the process of making logical conclusions
Recording opinions
Let’s practice making observations with some new images!!!

40. Step #1: Scientists Ask Questions/State the Problem
Scientists base their questions upon:
Observations (after information has been collected)
Prior knowledge
Related research
Why is this an important step???

41. Step #1: Scientists Ask Questions/ State the Problem
What questions can we ask about the behavior that we observed with the Japanese Macaques?

42. Step #2: Scientists Form a Hypothesis
Hypothesis= a testable explanation of a situation
Dr. Ron Wiley hypothesized that the use of isometric exercise to raise blood pressure during maneuvers might increase tolerance to g-force and prevent blackouts
How did he make this hypothesis?

43. Step #2: Scientists Form a Hypothesis
Hypothesis= a testable explanation of a situation
Theory = a well-tested explanation that unifies a broad range of observations

44. Step #2: Scientists Form a Hypothesis
Let’s form a hypothesis about why our Japanese Macaques are exhibiting this behavior
Make sure that this is a testable hypothesis!

45. Step #3: Design an Experiment
Experiment = an investigation of a phenomenon in a controlled setting to test a hypothesis
Let’s look at a new experiment:
A scientist observes that grass does not grow in a certain part of a lawn.
Hypothesis: The grass died because there was no water.

46. Step #3: Design an Experiment
Control Group = a group used for comparison.
The plot of grass that was not given extra water.
Experimental Group = the group exposed to the variable that is being tested.
The plot of grass that was given extra water.

47. Step #3: Design an Experiment
Variable = any factor that can affect the outcome of an experiment
Water, sunlight, disease, etc.
Independent Variable = the manipulated variable; what is changed by the experimenter.
Amount of water
Dependent Variable = the variable that is measured; the results.
Grass growth

48. Step #3: Design an Experiment
Constant = a factor/variable that doesn’t change during an experiment.
What are some constants in our grass experiment???

49. Step #4: Perform an Experiment/Gather Data
Data = Information gained from observations
Quantitative Data: numerical data (measurements of time, temperature, length, mass, area, etc.)
Grass experiment = Area of healthy grass vs. area of dead grass
Qualitative Data: descriptions of what our senses detect
Grass experiment = More healthy grass vs. less dead grass

50. Step #5: Analyze the Data
Questions that scientists ask:
“Has my hypothesis been supported?”
“Is more data needed?
“Are different procedures needed?”
Scientists work in groups to analyze data!
Tables and graphs are good tools for data analysis

51. Step #6: Report Conclusions
Scientists report their conclusions and findings in scientific journals (peer-reviewed journals)
What examples can you think of?

52. Step #6: Report Conclusions
Conclusions may:
Confirm original hypothesis
Disprove original hypothesis
Indicate that further research is needed
What other experiments could we do to test why the grass is not healthy?

53. Just for fun! Other cool behaviors exhibited by Japanese Macaques

54. They build snowballs for fun!!!

55. They groom other animals!

56. A Historical Example of the Scientific Method: Spontaneous Generation
Spontaneous Generation = the theory that life can arise from nonliving matter
Biogenesis Generation = the theory that living things come only from other living things
How are these two theories different???

57. Francesco Redi – Proposed Biogenesis Generation, Disproved Spontaneous Generation
How would the presence of maggots be explained by spontaneous generation?

58. Louis Pasteur – Disproved Spontaneous Generation
Simple organic molecules to complex organic molecules and became the building blocks of the first cells
Pasteur set up an experiment to refute spontaneous generation for microscopic life -
Louis Pasteur’s Experiment