Write a paragraph describing how earth would be different if photosynthetic plants had not evolved.

Photosynthetic plants photosynthesise carbon dioxide and water to produce oxygen and glucose. Without photosynthetic plants elvoving there eukaryotes would have extremely different respiratory systems. Eukaryotes (including plants) currently respire glucose using oxygen on a cellular level. If photosynthetic plants were not present there would be much less oxygen in the air. Eukaryotes therefore would evolve completely different ways of respiring to release energy.

In some developing nations the percentage of the animal protein from fish in the diet can be as high as 25 percent.  about 85% of fish caught is used for human consumption.  the remainder is converted into fishmeal and fish oil.