1. 4-3 The Diversity of Living Things

2. Levels of Classification
Pick-up Table 2, page 102

3. A. The Diversity of Living Things
1. Most scientists classify organisms into three domains and four kingdoms based on different characteristics.

4. A. The Diversity of Living Things
2. The cells of animals, plants, fungi, and protists all contain a nucleus. While cells of bacteria, fungi, and plants all have cell walls.

5. B. Archaea and Bacteria
1. Archaea differ from bacteria in their genetics and the makeup of their cell wall.

6. B. Archaea and Bacteria
2.Bacteria are microscopic, unicellular organisms that usually have a cell wall and reproduce by cell division.

7. C. Bacteria and the Environment
1. Bacteria can:
- break down the remains and wastes of other organisms and return the nutrients to the soil.
-recycle nutrients, such as nitrogen and phosphorus.
-convert nitrogen from the air into a form that plants can use.

8. C. Bacteria and the Environment
2. Escherichia coli or E. coli, is found in the intestines of humans and other animals and helps digest food and release vitamins that humans need.

9. D. Fungi
1. A fungus is an organism whose cells have nuclei, rigid cell walls, and no chlorophyll and that belongs to the kingdom Fungi.

10. D. Fungi
2. A mushroom is the reproductive structure of a fungus. The rest of the fungus is an underground network of fibers that absorb food from decaying organisms in the soil.

11. E. Protists
1. Protists are diverse organisms that belong to the kingdom Protista.
2. Some, like amoebas, are animal-like. Others are plantlike, such as kelp, and some resemble fungi.

12. E. Protists
3. Most protists are unicellular, microscopic organisms, including diatoms, which float on the ocean surface.
4. Another protist, Plasmodium, is the unicellular organism that causes the disease malaria.

13. F. Plants
1. Plants are multicellular organisms that make their own food using light energy from the sun and have cell walls.

14. F. Plants
2. Most plants live on land where they use their leaves to get sunlight, oxygen, and carbon dioxide from the air. While absorbing nutrients and water from the soil using their roots.

15. G. Gymnosperms
1. Gymnosperms are woody vascular seed plants whose seeds are not enclosed by an ovary or fruit.

16. H. Angiosperms
1. Angiosperms are flowering plants that produce seeds within fruit. Most land plants are angiosperms.

17. I. Invertebrates
1. Invertebrates are animals that do not have backbones.
2. Many live attached to hard surfaces in the ocean and filter their food out of the water, such as corals, various worms, and mollusks.

18. J. Vertebrates
1. Vertebrates are animals that have a backbone, and includes mammals, birds, reptiles, amphibians, and fish.
2. The first vertebrates were fish, but today most vertebrates live on land.