Chapter 28

Question 1

Protists (General Term) (3)

Answer 1

• Most are unicellular, some colonial and multicellular
• More structural and functional diversity than other eukaryotes (all functions carried out by organelles)
• Do not represent a monophyletic group

Question 2

Nutritional Diversity of Protists (3)

Answer 2

1. Photoautotrophs
2. Chemoheterotrophs
3. Mixotrophs - photoautotrophy and chemoheterotrophy

Question 3

Protists - 4 Eukaryotic Supergroups

Answer 3

1. Excavata
2. SAR Clade
3. Archaeplastida
4. Unikonta

Question 4

1. Excavata (3 Sub-Groups)

Answer 4

• Diplomonads/Parabasalids

- Euglenozoa

Question 5

Diplomonads/Parabasalids (4)

Answer 5

• No plastids
• Modified mitochondria
• Many prefer anaerobic environments
• Many are parasites

Question 6

Euglenozoa (3)

Answer 6

• Proteinaceous plates (pellicles)
• Photoautotrophic, mixotrophic, chemoheterotrophs
• Flagella: internal crystalline rod & rows of stiff hairs (pulls cells)

Question 7

2. SAR Clade (3 Sub-Groups)

Answer 7

• Stramenopiles
• Alveolates
• Rhizarians

Question 8

Stramenopiles (3)

Answer 8

• Two flagella; one with fine hairlike projections, other smooth; sometimes only found on reproductive structures
• Many cells found in the ocean - doubles every day
• Extracted for energy production - released more rapidly when buried

Question 9

Stramenopiles Sub-Groups (3)

Answer 9

1. Diatoms
2. Golden Algae
3. Brown Algae

Question 10

Diatoms (5)

Answer 10

• highly diverse
• unicellular and colonial
• Silica Frustules: counteracts with spines and lipids
• 25% of the primary productivity on Earth
• fossil deposits mined for diatomaceous earth

Question 11

Golden Algae (3)

Answer 11

• unicellular and complex colonies
• resistant cysts
• indicator fossils (cysts) to predict past climate change

Question 12

Brown Algae (5)

Answer 12

• multicellular, mostly marine
• thallus: body
• holdfast: anchor
• stripe: stemlike
• blade: leaflike

Question 13

Alveolates

Answer 13

• Series of sacs (alveoli) under plasma membranes

- Come back to Figure 28.1 in the textbook!

Question 14

Alveolates Sub-Groups (2)

Answer 14

1. Dinoflagellates

2. Apicomplexans

Question 15

Dinoflagellates (2)

Answer 15

• heterotrophic, mixotrophic and photosynthetic

- ex: red tides

Question 16

Apicomplexans (4)

Answer 16

• apical complex for penetrating host tissues
• mostly parasites of animals (multiple hosts)
• only ancestrally photosynthetic
• plasmodium = malaria

Question 17

Rhizarians (2)

Answer 17

• Many species in this group are amoebas that feed using pseudopodia
• Also includes flagellated mon-amoeboid protists that also feed with pseudopodia

Question 18

Rhizarians Sub-Group

Answer 18

Foraminiferans

Question 19

Foraminiferans (5)

Answer 19

• have porous shells called tests
• single-celled but up to several cms
• pseudopodia extend through pores to aid swimming and feeding
• abundant in the fossil record
• informs studies on past climate

Question 20

3. Archaeplastida (3)

Answer 20

• Includes red algae, chlorophytes, charophytes, and land plants
• unicellular and multicellular
• the base of the food web in many aquatic communities

Question 21

Archaeplastida Sub-Groups (3)

Answer 21

1. Red Algae
2. Chlorophytes
3. Charophytes

Question 22

Red Algae (3)

Answer 22

• no flagellated gametes at any stage of their life cycle
• 6000 species, mostly marine
• typically smaller

Question 23

Chlorophytes

Answer 23

-Have a chloroplast structure similar to land plants

Question 24

Charophytes

Answer 24

-Most closely related to land plants

Question 25

4. Unikonta

Answer 25

- Currently argued whether or not this is actually the first lineage to diverge from other eukaryotes - Slime Molds

Question 26

Slime Molds (3)

Answer 26

- large, but still a single cell - divided by plasma membranes and has many nuclei - many mitotic nuclear divisions that are not followed by cytokinesis