Yes, that is true. What is your question?
<span>The group includes their common ancestor but also the seeded descendants of that same ancestor.</span>
Here is a good resource:
https://nhlbi.nih.gov/health/educational/lose_wt/eat/calories.htm
10 pounds
10% of energy moves on through each trophic level so if a chicken ate 10 pounds of a producer that would be equivalent to the fox eating 1 pound of chicken. (10 times .1 = 1)