1. Chapter 1: The Science of Life

2. Section 1: The World of Biology
Objectives
Relate the relevance of biology to a person’s daily life
Describe the importance of biology in human society
List the characteristics of living things
Summarize the hierarchy of organization within complex multicellular organisms
Distinguish between homeostasis and metabolizm and between growth, development, and reproduction

3. Ch. 1.1 The World of Biology Biology and You
Biology is the study of life and can be used to both solve societal problems and explain aspects of our daily lives

4. Ch. 1.1 The World of Biology Characteristics of Life
Living things share the same 7 characteristics:
Organization and cells
Response to stimuli
Homeostasis
Metabolism
Growth and development
Reproduction
Evolution

5. Ch. 1.1 The World of Biology Characteristics of Life
Organization is the high degree of order within an organism’s internal and external parts and in its interactions with the living world
A cell is the smallest unit of an organism that can perform all life’s processes

6. Ch. 1.1 The World of Biology Unicellular vs. Multicellular
Some organisms, such as bacteria, are made up of a single cell and are called unicellular organisms
Some organisms are
made up of many cells
and are called
multicellular organisms

7. Ch. 1.1 The World of Biology Organization and Cells
Multicellular organisms are made up of many cells and show a hierarchy of organization going from the organism to the atom

8. Ch. 1.1 The World of Biology Characteristics of Life
Response to Stimuli
A living organism can respond to a stimulus—a physical or chemical change in the internal or external environment

9. Ch. 1.1 The World of Biology Characteristics of Life
Response to Stimuli

10. Ch. 1.1 The World of Biology Characteristics of Life Homeostasis
All living things have mechanisms that allow them to maintain stable internal conditions. Homeostasis is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing.

11. Homeostasis

12. Homeostasis

13. Ch. 1.1 The World of Biology Characteristics of Life Metabolism
Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment.

14. Ch. 1.1 The World of Biology Characteristics of Life
Growth and Development
The growth of living things results from the division and enlargement of cells
Development is the process by which an organism becomes a mature adult

15. Ch. 1.1 The World of Biology Characteristics of Life Reproduction
Living organisms pass on hereditary information from parents to offspring, also called reproduction

16. Ch. 1.1 The World of Biology Characteristics of Life
Change through time
Populations of living organisms evolve or change through time

17. Ch. 1.1 The World of Biology
Living vs. Non-Living

18. Ch. 1.2 Themes In Biology Objectives
Identify three important themes that help explain the living world
Explain how life can be diverse, yet unified
Describe how living organisms are interdependent
Summarize why evolution is an important theme in biology

19. Ch. 1.2 Themes In Biology Diversity and Unity of Life
Life is so diverse, or full of variety. Yet, life is also characterized by unity, or features that all living things have in common

20. Ch. 1.2 Themes In Biology Diversity and Unity of Life
The tree of life shows that all living things have descended with modification from a single common ancestor. Yet, there are many different lineages, or branches, representing different species

22. Ch. 1.2 Themes In Biology Evolution Natural Selection
Decent with modification; the process in which the inherited characteristics within populations change over generations, such that genetically distinct populations and new species can develop
Natural Selection
Organisms that have certain favorable traits are better able to survive and reproduce successfully

24. Science as a Process
Science is characterized by an organized process, called the scientific method, to learn how the natural world works
There is no single method, but all involve a certain series of steps

25. Steps of the Scientific Method
Observation
The act of perceiving a natural occurrence that causes someone to pose a question
Hypothesis
A proposed explanation for the way a particular aspect of the world functions
Prediction
A statement that forecasts what would happen in a test situation if the hypothesis were true

26. Steps of the Scientific Method
Experiment
Used to test the hypothesis and its predictions
Analysis and Drawing Conclusions
Once the experiment is ended the data is analyzed and conclusions are formed
Communication
Results and conclusions are communicated to peers and the public

27. The Scientific Method

28. The Scientific Method Observations
Start with an unexplainable observation about nature
Example: Owls are nocturnal, and thus hunt at night…how are they able to do this?

29. The Scientific Method Forming a Hypothesis
A good hypothesis can answer a question in a testable way
Example: How do owls hunt at night?

30. The Scientific Method Design an Experiment
Control group: normal standard against which biologists can compare results from experimental group
Experimental group: identical to control group except for one factor…
Independent variable: variable manipulated to test questions/hypothesis

31. The Scientific Method Run the experiment Collect data Repeat
Draw conclusions on the data

32. The Scientific Method
Another example….My flashlight isn’t working…come up with an answer using the scientific method…

33. Ch. 1.4 Tools and Techniques
Microscopes
Tools that extend human vision by making enlarged images of objects; examples in biology: cells, cell parts, molecules
Types of Microscopes
Compound light microscope
Scanning electron microscope (SEM)
Transmission electron microscope (TEM)

34. Ch. 1.4 Tools and Techniques
Light Microscopes
Shines light through a specimen, with two lenses that magnify the image.
Specimen must be thin enough for light to pass through it
If too large, specimens are cut into smaller, thinner pieces

35. Ch. 1.4 Tools and Techniques

36. Ch. 1.4 Tools and Techniques

37. Ch. 1.4 Tools and Techniques
Magnification
All microscopes come with an ocular lens (or lenses) and objective lenses
Ocular (10x magnification)
Objective (4x, 10x, 100x magnification)
To calculate the power of magnification multiply the ocular magnification by the objective lens magnification being used

38. Ch. 1.4 Tools and Techniques
Electron microscopes are used to see even more detail of an object
Utilizes a beam of electrons to produce a larger image of the specimen
Higher magnification and resolution than light microscopes
Always black and white images
Uses a vacuum which makes it unable to view live specimens

39. Ch. 1.4 Tools and Techniques
Scanning Electron Microscope
Passes a beam of electrons over the specimen’s surface.
Sprays specimen with metal coating, which emits a shower of electrons.
Produces a 3D image that can be magnified up to 100,000 times!

40. Ch. 1.4 Tools and Techniques
Transmission Electron Microscope
Transmits beam of electrons at a very thin slice of a specimen
Greater resolution achieved
Up to 200,000x magnification!