What is the possible consequences of adding an organism to a food chain?

If an invasive species is added into a food chain/web, it becomes overpopulated/a pest because it has no natural predators.

It can also disrupt the food chain/web by eating the food supplies of the native organism leading to competitions.

photosynthesis makes the glucose that is used in cellular respiration to make atp. the glucose is then turned back into carbon dioxide, which is used in photosynthesis. while water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.