AP BIOLOGY

Detailed explanation-1: -The first organisms to evolve on earth were bacteria. They come under the category of prokaryotic heterotroph. Due to absence of oxygen at that time, these first bacteria were anaerobic and also heterotrophic due to lack of photosynthesis process.

Detailed explanation-2: -It has been theorized that the first-ever prokaryotes appeared a billion years after the earth’s crust formation. They initially existed as non-oxygen synthesizing, photosynthetic bacteria that accumulated to form large mounds known as stromatolites.

Detailed explanation-3: -The first fossils of prokaryotic (bacterial) cells are known from 3.5 and 3.4 billion years ago.

Detailed explanation-4: -Prokaryotes came first, with speculations stating that they appeared at least 3.8 billion years ago. Prokaryotes are underdeveloped cells, undifferentiated organelles with no nuclei. They have circular DNA. It suggests that prokaryotes evolved first.

Detailed explanation-5: -Prokaryotic cells which are facultative anaerobic make ATP by aerobic respiration if oxygen is present, but can also survive without oxygen.