1. Classification systems change as scientists learn more.
Notes for B 2.3
Classification systems change as scientists learn more.

2. Taxonomy changes as scientists make discoveries.
Early scientists described 2 kingdoms:
Plants: green and nonmoving
Animals: moving organisms

3. Three Domains
Microscopes and other advances in technology show that there are basically 3 different types of cells.
Kingdoms are arranged into 3 larger groups called domains: Bacteria, Archaea, and Eukarya.

4. Three Domains Bacteria: includes bacteria kingdom No nucleus
Unicellular
Vary in how they get energy

5. Archaea Kingdom Archaea No nucleus (prokaryotic) Unicellular
Vary in how they obtain energy
Distinctive chemistry and live in extreme environments

6. Eukarya Includes Kingdoms Protista, Fungi, Plantae, and Animalia
Eukaryotic (have nuclei)
Some unicellular, most multicellular
Vary in the ways they obtain food
See chart on page B 61.

7. Six Kingdoms Plantae Animalia Protista Fungi Archaea Bacteria
See pages 62 and 63 for an overview of all of these kingdoms you studied in seventh grade.

8. The two most familiar kingdoms are plants and animals.
Carolus Linneaus divided all the species he identified into these 2 groups.
Plantae DNA stored in a nucleus
Can carry out photosynthesis to make sugars
Contain cell walls around their cell membrane
Cannot move from place to place
Multicellular

9. Animalia More than 90% of named species are insects.
Obtain energy by eating organisms or by eating food made by other organisms
Can move around for at least part of their lives
Most have mouths and nervous systems
Have nuclei (eukaryotic)
No cell walls

10. Other organisms make up four more kingdoms.
Linnaeus: called mushrooms, molds, and their relatives plants
Archaea, Bacteria, and Protista are mostly microscopic.
Most organisms on Earth are classified as bacterial or archaea—prokaryotic, small, and simple.

11. Protista Most unicellular Large, complex with a true nucleus
Some eat other organisms.
Some make their own food.
Some resemble fungi.
Most live in water or sea water
Seaweeds
Some scientist think this should be divided into different kingdoms.

12. Fungi Yeasts Molds Downy Mildew Most have cell walls
Remain rooted in one place
Many act as decomposers

13. Archaea Resemble bacteria in size and shape Genetic differences
Appear to be related to eukaryotes, but do not have nuclei
Cell structure differs from bacteria
Live in many environs, especially the oceans
Some live in extreme environs such as geysers, hot springs, hot vents, salty ponds etc.

14. Bacteria Live nearly everywhere on Earth Helpful/harmful Unicellular
Prokaryotes (no nucleus)
Most have cell walls, but not the kind plants have
Reproduce quickly by binary fission

15. Species and environments change.
Over a million species named
Estimated millions—maybe tens of millions– not yet discovered
Species evolve over time as individual organisms and environments change.
Changes may result in pressures that affect living space, availability of food or other resources, or from other organisms.

16. Review Questions for B 2.3
Page 67B

17. Number 1
Plantae
Animalia
Protista
Fungi
Bacteria
Archaea

18. Number 2
Organisms are sorted according to general traits.

19. Number 3
See pages

20. Number 4 Plants use the sun’s energy and air to make sugars.
Fungi take in nutrients from their surroundings.

21. Number 5 No—does not have a nucleus
Yes—the membrane and DNA are like a nucleus

22. Quiz B 2.3 Fill ins: Animalia Archaea species Protista Bacteria Fungi
Domains Plantae
(6 terms used)
What are the 3 domains? List 2 traits that are used to classify organisms into each domain.