Habitat: marine mostly ( can be fresh water some airborne)
Pigments: Chl a +c plus peridinin ( brown pigment) + carotenoids However approx. 45% do not contain any pigments and ingest food ( heterotrophic)
Cell wall: absent in a few but most have armor-like cellulose plates interior to the plasma membrane.
Storage: starch as in the greens & dinoflagellates
Motility: with 2 tinsel flagella in their own grooves.- both are lateral but one wraps around the waist and the other trails like a rudder resulting in a spinning motion.
Reproduction: mostly asexual though some sexual. Division unusual in that chromosomes remain condensed with no histones and a persistent nuclear envelope. 40X DNA amount found in a human cell!
Ecological significance:
1. Red Tide produces toxins that kill fish and shellfish (?). The accumulated toxin in the shellfish is consumed by humans and this neurotoxin causes paralysis.
2. Some species are luminescent when agitated - tropical seas.
3. Some are symbionts with sponges, jellyfish and corals.
