1. Classifying and Exploring Life
Chapter 1
Classifying and Exploring Life

2. All living things, or organisms:
Are made up of a cell or cells
Grow and develop
Reproduce
Respond
Maintain homeostasis
Use energy

3. Characteristics of life:
All living things:
Organized by their cell(s).
Unicellular organisms have only one cell

4. Multicellular organisms have more than one cell.

5. Multicellular organisms have a greater level of organization because groups of cells (tissues) function together

6. 2. Grow and develop. 3. Reproduction. With a mate Without a mate
By increasing cell size
Or cell number
The changes that occur during a lifetime are called development.
3. Reproduction.
With a mate
Without a mate

7. 4. Respond to stimuli.
Stimuli may be internal (like hunger)
Or external (bright light, for example)

8. 5. Maintain homeostasis: a stable, internal environment.
6. Use energy:
for making new cells
chemical reactions
transporting materials

9. For most organisms, the energy they use originally came to Earth from the Sun.

10. Lesson 2 Classifying living things

11. Classifying living things
Living things can be grouped by their characteristics.
Aristotle separated organisms into 2 groups: plants and animals.

12. Linnaeus used 2 kingdoms to group organisms. (1700’s)
Determining kingdoms
Linnaeus used 2 kingdoms to group organisms. (1700’s)
5 kingdom system began in 1969: Monera, Protista, Fungi, Plantae, and Animalia.

13. Current system uses domains. The 3 domains are: Bacteria Archaea
Determining kingdoms
Current system uses domains.
The 3 domains are:
Bacteria
Archaea
Eukarya
Then the organism gets classified into 1 of 6 kingdoms.

14. A naming system for organisms using two Latin words.
Scientific Names
A naming system for organisms using two Latin words.
The first word is the organism’s genus
example: Ursus
The second word is the organism’s species
example: arctos
Ursus arctos is the scientific name for the brown bear.

15. A species is a group of organisms that have similar traits and produce fertile offspring.
Similar species are grouped into 1 genus.
Similar genera are grouped into 1 family.
Similar families get grouped into orders.
Orders get grouped into classes.
Classes into phyla.
Phyla into kingdoms.

17. Dichotomous Keys: pairs of descriptions that lead to the identification of an unknown organism. (see p. 22 in text)

18. Classification tools:
Cladograms: branched diagram that shows the relationship among organisms, including common ancestors. (also tree or branch diagrams

19. Lesson 3 exploring life

20. Light microscopes use light and lenses to magnify the images.
The Microscope
Enables us to see living things that are too small for us to see on our own
Light microscopes use light and lenses to magnify the images.
Electron microscopes use a magnetic field to focus electrons on or through an object.

21. We will be using the compound light microscope in this class
Magnification of the image is found by multiplying the magnification of the eyepiece with the magnification of the objective lens.
Eyepiece x Objective = total magnification
Ex: 10x X 40x = 400x
We will be using the compound light microscope in this class

22. Microscope comparison
light
electron
Can enlarge image up to X
Able to view living or nonliving organisms
Uses lenses to magnify the specimen
Can enlarge image up to 100,000 X
Able to view thinly sliced, dead organisms
Uses electron beams for magnification

23. Images seen through these microscopes
Compound light
Scanning electron
Blood cell
Blood smear