A Hot Topic: Endosymbiosis
This is a large protozoan cell called a ciliate, live under the microscope. The smaller green objects are living plant cells resident inside it. The image illustrates a seminal evolutionary process. During the dawn of life, cells began eating other cells. To survive, the prey cells resisted digestion and eventually, instead of being regurgitated, they took up residence in the predator, creating a composite cell that combined the capabilities of each partner. This process, "endosymbiosis", profoundly increased cellular complexity by creating mitochondria and chloroplasts. One lineage of endosymbiotic cells generated the green algae which in turn gave rise to the green land plants. So every land plant owes its existence to an ancient endosymbiotic event because every chloroplast came from an ancestral algal cell.
Endosymbiosis has happened many times and our DVD: The Kingdom Protista: the dazzling world of living cells shows several examples. Also illustrated is "secondary endosymbiosis" where symbiotic cells were themselves eaten and became symbionts a second (and even a third !) time.
Links to reviews appearing in the Journal of Phycology.
The Kingdom Protista: The Dazzling World of Living Cells
Protist (Leander, Keeling) dvd review
DIATOMS: Life in Glass Houses
Diatom (Siver) dvd review
Remarkable Plants: the Oedogoniales
Oedogoniales (Cook) dvd review