Chapter 28 Protists

Question 1

Carolus Linnaeus?

Answer 1

Foundations for modern biological nomenclature.

Question 2

Ernst Haeckel?

Answer 2

Based on microscopic analysis proposed 3rd Kingdom.

Question 3

Herbet Copeland?

Answer 3

Based on e-microscopic analysis proposed 4th Kingdom.

Question 4

Stanier?

Answer 4

Pushed division of Prokaryotes & Eukaryotes to higher level.

Question 5

Robert Whittaker?

Answer 5

5th Kingdom based on nutritional differences.

Question 6

Carl Woese?

Answer 6

Switch from outward appearance, to genetic similarity & common ancestry.

Question 7

International Society of Protistologists?

Answer 7

genetic relatedness

Question 8

Order of classes?

Answer 8

Domain, SuperGroups, Major Claddes, Kingdoms

Question 9

What are protists?

Answer 9

Protists treated as the Kingdom Protista - a catch-all for all species that did not fit into one of the other Kingdoms:

Question 10

Charateristics of Excavata?

Answer 10

asymmetric body shape
excavated ‘feeding groove’
one or more flagella
modified mitochondria

Question 11

Charateristics of Diplomonads?

Answer 11

bilateral symmetry
two nuclei and multiple flagella
mostly anaerobic parasites
mitochrondria reduced as unable to synthesize ATP

Question 12

Charateristics of Parabasalids?

Answer 12

flagella & undulating membrane (helps with locomotion by creating wave-like movement)
mitochondria reduced to Hydrogenosomes  produce H2 gas as byproduct, helps in anaerobic environments

Question 13

Charateristics of Euglenozoans?

Answer 13

mostly free-living, single celled freshwater and marine
possess stigma & photo-receptor  an eyespot & light dector that can sense and orient towards light
alternate within between heterotrophic and autotrophic…

Question 14

What are diatoms?

Answer 14

unicellular algae with a silica-based cell wall.

Question 15

What are Alveolates?

Answer 15

presence of alveoli, which are small, flattened vesicles beneath the cell membrane

Question 16

What are dinoflagellates?

Answer 16

two flagella wrapped around cellulose plates

Question 17

What are Apicomplexans?

Answer 17

mostly intracellular parasites, unique organelle apicoplast to help invade host cells

Question 18

What are Ciliates?

Answer 18

heterotrophic protists, presence of cilia, hair-like structures for movement, feeding, sensing

Question 19

What are Forams ?

Answer 19

marine benthivores (calcium carbonate)

Question 20

What are Radiolarians?

Answer 20

marine zooplankton (silica-based)

Question 21

What are Unikonta?

Answer 21

-single flagellum
-actin filaments  play role in cell movement, shape, and division
-monophyletic  one common ancestor and all its descendants

Question 22

What are Amoebozoans?

Answer 22

-lobe or tube-shaped pseudopodia
slime moulds (Mycetozoans),
-amoebas (Tubulinids), parasites (Entamoebas)

Question 23

Four Steps of Evolution of Multicellularity

Answer 23

1. Model for Multicellular Evolution
2. Cellular Cooperation and Conflict
3. Signal Transduction and Communication
4. Genetic Studies

Question 24

1. Model for Multicellular Evolution

Answer 24

Cellular slime molds provide a key example of how multicellularity may have evolved. They spend most of their life cycle as single-celled amoebae. However, under certain conditions (such as starvation), they aggregate to form a multicellular structure called a “slug” that can move and eventually differentiate into different cell types to form a fruiting body.

Question 25

2. Cellular Cooperation and Conflict

Answer 25

Cooperation and Altruism: The aggregation of individual cells into a multicellular form requires cooperation between cells. Cheating and Conflict: Not all cells act cooperatively. In some cases, there are "cheating" cells that avoid the sacrifice and try to become spores without participating in the stalk.

Question 26

3. Signal Transduction and Communication

Answer 26

Cell Signaling: Cellular slime molds exhibit complex cell signaling processes that help coordinate the aggregation of individual amoebae into a multicellular organism. Developmental Pathways: The process through which these cells form different structures, like the stalk and spores, provides insight into developmental biology, including differentiation, morphogenesis, and pattern formation, which are all critical in the evolution of complex organisms.

Question 27

4. Genetic Studies

Answer 27

Genetics and Evolution: The study of Dictyostelium and other slime molds helps researchers understand the genetics of single-celled versus multicellular states, including the genes involved in cell division, signaling, and differentiation.

Question 28

What are Opisthokonts?

Answer 28

single posterior flagellum heterotrophic  fungi = absorptive heterotrophs; animals = ingestive het.