Chapter 28 terms/concepts/protists

Question 1

How are protists nutritionally diverse?

Answer 1

The are photoautotrophs, heterotrophs, and mixotrophs, which combine photosynthesis and heterotrophic nutrition

Question 2

Where did protist diversity come from?

Answer 2

Endosymbiosis

Question 3

Endosymbiosis in Eukaryotic Evolution

Answer 3

Heterotrophic eukaryote engulfs a cyanobacteria and the cyanobacteria evolves, forming plastid organelles and diverging red and green algae. Red and green algae are then enveloped by another hetertrophic eukaryote and give rise to eukaryotic organisms

Question 4

4 supergroups of eukaryotes

Answer 4

1. Excavata
2. SAR
3. Archeoplastida
4. Unikonta

Question 5

Excavata (general characteristics)

Answer 5

Defined by a feeding groove, modified mitochondria, and unique flagella

Question 6

Three monophyletic groups of Excavata (and their general characteristics, and an example of the first Excavata)

Answer 6

Diplomonads and Parabasalids (which lack plastids and have modified mitochondria and live in anaerobic environments) - in example of diplomonads is Giardia intestinalis (a parasite that causes a diarrheal disease).

Euglenozoans , which are predator heterotrophs, autotrophs (photosynthesis) a mix of both (mixotrophs) and parasites. Their main feature is a spiral/crystalline rod inside their flagella

Question 7

SAR super group include:

Answer 7

1. Stramenopiles
2. Alveolates
3. Rhizarians

Question 8

General characteristics and subcategories of stramenopiles

Answer 8

Very important photosynethetic organisms

Most have “hairy” and “smooth” flagellum - the hairy one is longer than the smooth one

They include diatoms, golden algae, and brown algae

Question 9

General features of Diatoms

Answer 9

(Stramenopile) Unicellular algae with a unique two-part, glass like wall of silicon

They are a major component of phytoplankton and are incredibly diverse, and help remove carbon from the atmosphere

Question 10

General features of Brown algae

Answer 10

(Stramenopile) Largest, most complex algae. Multicellular and most are marine. Include many seaweeds

Have leaflike blades, stem-like stipes, and root-like holdfasts

Question 11

General characteristics of Alveolates

Answer 11

Membrane-enclosed sacs (alveoli) just under the plasma membrane

Question 12

Apicomplexans

Answer 12

Subgroup of alveolates that are mostly parasitic, some cause serious human diseases

Question 13

Draw the life cycle of the Plasmodium parasite

Answer 13

draw

Question 14

General characteristics of Rhizarians

Answer 14

Many Rhizarians are ameobas

They have pseudopodia which are extensions of the cell surface, but rhizarian ameobas have differing pseudopodia in that they are thread-like

Question 15

General features of red algae

Answer 15

(Supergroup Archeoplastida) Have a accessory pigment phycoerythrin that masks the green of chlorophyll

Color can vary from greenish-red in shallow water to dark red/almost black in deep water - this is due to algae absorbing light at different wavelengths

Multicellular and large

Most abundant large algae in coastal waters

Question 16

General features of green algae

Answer 16

They are a paraphyletic group

two main groups are charophytes and the chlorophytes, and charophytes are the most closely related to plants

Question 17

Alternation of generations of Chlamydomonas

Answer 17

draw life cycle

Question 18

Heteromorphic

Answer 18

Structurally different generations

Question 19

Isomorphic

Answer 19

Structurally similar generations

Question 20

Sporophyte

Answer 20

Diploid generation in the alternation of generations, which produce haploid spores (zoospores)

Question 21

Gametophyte

Answer 21

Zoospores that have developed into a haploid generation, produce gametes via mitosis

The fertilization of gametes creates a diploid zygote and thus a new sporophyte

Question 22

Volvox

Answer 22

(Archeaoplastida) colonial green algae

Question 23

Charophytes

Answer 23

Green algae that are the closest relatives of land plants

Question 24

Chlorophytes

Answer 24

Green algae that live in freshwater but can be marine as well, live in damp soil, others live in snowy environments, some live symbiotically with fungi to form lichens (leaflike growth on rocks)

Question 25

Subgroups that make up the final supergroup, Unikonta

Answer 25

Ameobozoans and opisthokonts

Question 26

How can you tell the difference between amoebozoans and rhizarian amoebas?

Answer 26

Rhizarian amoebas have more threadlike pseudopodia than ameobozoans (more smooth like pseudopodia)

Question 27

Examples of ecological roles of protists

Answer 27

Some are symbionts:

Dinoflagellates that nourish coral polyps that build reefs

Wood digesting symbionts in the gut of parasites

Photosynthetic protists are important producers that obtain energy from the sun, converting CO2 to organic materials

They also are critical to aquatic systems as well

Question 28

Opisthokonts

Answer 28

include fungi, choanoflagellates, and animals

Question 29

Slime mold

Answer 29

A slug-like aggregate of ameobozoan protists that form if food is depleted in the environment