AP BIOLOGY

Detailed explanation-1: -Evidence shows that plants evolved from freshwater green algae, a protist. The similarities between green algae and plants is one piece of evidence. They both have cellulose in their cell walls, and they share many of the same chemicals that give them color.

Detailed explanation-2: -The characteristic features of algae include autotrophic chlorophyll-bearing thalloid plant body, lacks sterile tissue around its reproductive structures, and zygote development is by mitosis or meiosis but not via embryo formation.

Detailed explanation-3: -Like green plants and algae, some purple and green sulphur bacteria are capable of synthesising their organic food in presence of light, which is known as bacterial photosynthesis. This process is anoxygenic, that is they do not produce or evolve O2.

Detailed explanation-4: -Both Prototheca and Helicosporidium are non photosynthetic, and since most phylogenetic analyses have depicted Helicosporidium and Prototheca as members of a monophyletic clade, it is hypothesized that the loss of photosynthesis represents a synapomorphic character for these algae.