Biology / Unit 9 Bio 2013 short lesson, about 20 seconds
Excavata
Captions available
The idea
Excavata is defined by an asymmetrical feeding groove "excavated" from one side of the cell, a criterion spanning free-living, photosynthetic, and parasitic members.
In practice
Euglena, a free-living, mixotrophic excavate, carries a chloroplast from secondary endosymbiosis, and an eyespot that senses light.
Where people slip
Excavata's defining feeding groove says nothing about nutrition mode— the supergroup includes photosynthetic, heterotrophic, and parasitic lineages side by side.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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