Practice question

Endosymbiotic theory explains origin of mitochondria and chloroplasts from engulfed aerobic bacteria and cyanobacteria respectively. Evidence includes double membranes, circular DNA, 70S ribosomes and division similar to bacteria. Lynn Margulis championed this in 1967 synthesizing cytological and molecular data, now supported by phylogenomics. The theory accounts for eukaryotic complexity via symbiotic mergers rather than gradual invagination. Attribution to Lynn Margulis reflects her influential articulation establishing symbiogenesis as major evolutionary mechanism. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype and environment.