Question

5. Refer to the image. Phylogenetic relatianships based on chloroplast genes Brown algae Diatoms Most photosynthetic dinoflagellates Cryptophyte algae Red algae Red algae Phylogenetic relationships based on nuclear genes Opisthokonts Amoebozoans GlaucocystophytesArchaeplastids Red algae Green algae Diatoms Brown algae -Stramenopiles Green algae Euglenids Green algae Chlorarachniophyte algae Dinoflagellates -Alveolates Chlorarachniophyte algae Green algae Green algae Green algae Green algae Land plants Glaucocystophytes Rhizarians Cryptophyte algae Euglenids - Excavates Cyanobacteria ologye How Life Work, Third Edition o 2019 Macmlan Learning Phylogenies based on sequences from organellar genomes and nuclear genomes from the same group of species yield phylogenetic trees with different branching pattems. How is this possible? Nuclear and organellar genes evolved at different rates, obscurlng evolutionary relationships Endosymbiosis makes this possible. The genome of the chloroplast is more closely related to members of the group In which it orlginally evolved, whereas the nuclear genome of the engulfing organism has its own evolutlonary trajectory Endosymbiosis makes this possible. Transfer of genetic materlal from the genome of the endosymbiont to the host results in two different phylogenles, host and endosymbiont. The host genome continues to accumulate mutations, but the endosymbiont genome cannot For organelles like chloroplasts, no mutations can occur, or photosynthesis would stop and the organism would die. The nuclear genome can accumulate mutations, so it can continue to evolve.

Answer 1

b. Endosymbiosis makes this possible. The genome of the chloroplast is more closely related to the members of the group in which it originally evolved, whereas the nuclear genome of the engulfing organism has its own evolutionary trajectory.

As a result of endosymbiosis, the phylogenies based on sequences from organellar genomes and nuclear genomes from the same group of same have phylogenetic trees with different branching patterns.