Question

Photosynthetic eukaryotes contain both mitochondria and chloroplasts. Which sequence most likely describes the evolution of this group?

a) Mitochondria evolved first, followed by the development of chloroplasts.
b) Chloroplasts evolved first, followed by the development of mitochondria.
c) Mitochondria and chloroplasts evolved independently.
d) This evolution cannot be explained through current scientific understanding.

Answer 1

The evolution of photosynthetic eukaryotes involved mitochondria evolving before chloroplasts, supported by the endosymbiotic theory where mitochondrial origin preceded chloroplasts. Option a is correct

Step-by-step explanation:

The sequence that most likely describes the evolution of photosynthetic eukaryotes that contain both mitochondria and chloroplasts is that mitochondria evolved first, followed by the development of chloroplasts. This conclusion is supported by the endosymbiotic theory, which posits that mitochondria and chloroplasts originated from endosymbiotic events with prokaryotic organisms.

The evidence suggests that an ancestral eukaryotic cell first engulfed an aerobic bacterium, which evolved into the mitochondria, and then, during a later event, consumed photosynthetic bacteria that evolved into chloroplasts.