Chapter 28: Protists (3) Flashcards
What are the characteristics of dinoflagellates?
They are abundant components of both
marine and freshwater phytoplankton
- Nutrition: diverse group of aquatic
– phototrophs,
– mixotrophs, and
– heterotrophs
What are “red tides”?
Toxic “red tides” are caused by periods
of dinoflagellate blooms
What are the characteristics of Apicomplexans?
- Apicomplexans are parasites of animals, and some cause serious human diseases
- One end, the apex, contains a complex of
organelles specialized for penetrating host
cells and tissues - Most have sexual and asexual stages that
require two or more different host species for completion
Apicomplexans spread as infectious cells called _______.
- They spread as infectious cells called
sporozoites
What are the characteristics of Ciliates?
- Ciliates, a large varied group of protists, use cilia to move and feed
- They have large macronuclei and small micronuclei
- Genetic variation results from conjugation, in which two individuals exchange haploid micronuclei
What are the characteristics of rhizarians?
- Many species in the rhizarian clade are amoebas
- Rhizarian amoebas differ from amoebas in other clades by having threadlike pseudopodia
- Rhizarians include radiolarians, forams, and cercozoans
What is psudeopodia?
- Amoebas are protists that move and feed by pseudopodia, extensions of the cell surface
What are the characteristics of radiolarians?
- Marine protists called radiolarians have delicate, symmetrical internal skeletons that are usually made of silica
- Pseudopodia of radiolarians radiate from the central body
- Radiolarians use pseudopodia to engulf microorganisms through phagocytosis
What are the characteristics of forams?
- Foraminiferans, or forams, are named for
porous, generally multichambered shells, called tests - Many forams have endosymbiotic algae
What is the function of pseudopodia in forams?
Pseudopodia extend through pores in the tests and function in
– swimming
– feeding
– tests formation
What can fossilized forams be used for?
The magnesium content in fossilized forams can be used to estimate changes in ocean temperature over time
______and _______are the closest
relatives of land plants
Red algae and green algae are the closest
relatives of land plants
What are the groups under archaeplastida?
Archaeplastida is the supergroup that includes
– red algae,
– green algae, and
– land plants
Red algae are reddish in colour due to accessory pigment called ________, which masks the green of chlorophyll
Red algae are reddish due to accessory pigment called phycoerythrin, which masks the green of chlorophyll
_________ are the most abundant large algae in coastal waters of the tropical oceans
Red algae are the most abundant large algae in coastal waters of the tropical oceans
What are the characteristics of green algae?
- Green algae are named for their grass-green chloroplasts
- Plants are descended from green algae
- Green algae are a paraphyletic group
What are the two groups under green algae?
The two main groups are:
– chlorophytes and
– charophyceans
What are the characteristics of Most chlorophytes?
Most chlorophytes live in fresh water, although many are marine
* Includes more than 7000 species
- Other chlorophytes live:
– in damp soil,
– as symbionts in lichens, or
– in environments exposed to intense visible and ultraviolet radiation
How did Larger size and greater complexity evolve chlorophytes?
- formation of colonies from individual cells
- formation of true multicellular bodies by cell division and differentiation (e.g., Ulva)
- repeated division of nuclei with no cytoplasmic division (e.g., Caulerpa)
What are the 2 key roles protists play in their habitats?
Protists play two key roles in their habitats:
– that of symbiont and
– that of producers
What are some examples of protist symbionts?
Some protist symbionts benefit their hosts
– dinoflagellates nourish coral polyps that build reefs
– wood-digesting protists digest cellulose in the gut of
termites
