Question

In the energy pyramid below, calculate the amount of energy that is passed up from one trophic level to the next, assuming only 10% of the energy from the previous level is available for the next level. For each trophic level, circle all the words that apply to identify each organism as either a producer or consumer and as either an autotroph or a heterotroph. If the organism could be considered a predator and/or prey, circle those words also. 

 Questions

 1. Assume that the grasshopper in the food pyramid above must eat half its body weight in grass each day. If an average-size grasshopper weighs 2 grams, and 1 blade of grass weighs 0.1grams (one tenth of a gram), how many blades of grass does the grasshopper need to eat each day? 

 2. Assume a snake must eat 5 grasshoppers per day, while an eagle must eat 2 snakes per day. Use this information along with your answer from Question #1 to calculate how many blades of grass are needed to keep an eagle alive for a day?

 3. How many blades of grass are needed to support a family of four eagles for a week?

Answer 1

Calories transferred:

1) Calories transferred to grasshopper is 1000 calories

Calories available in the grass is 10000 calories and from the given question only 10% of calories are transferred to next tropic level so we can say that 10% of 10000 calories which makes up to 1000 calories which are transferred to grasshoppers.

          Calories from plants transferred to grasshoppers= 10000 x 10/100=1000 calories

2) Calories transferred to snake is 100 calories

As the 10% calories from the grasshopper is transferred to next level so 10% of 1000 calories of grasshopper makes around 100 calories so the snake gets energy of 100 calories

Calories transferred to snake is= 1000(grasshopper energy) x 10/100=100 calories

Questions:

1) Grasshopper must eat 10 blades of grass

Grasshopper weight is 2 gm and it must eat half of its weight to survive that means it should consume 1 grams of grass and if one blade of grass weighs 0.1 grams a grasshopper must eat 10 blades of grass to survive.

                         

                                                             =0.1 gmx 10 blades of grass= 1 gm

2) 100 blades of grass

5 Grasshoppers keep a snake alive an one grasshopper requires 10 blades of grass which means nearly 50 blades of grass are required for five grasshopper which will make only one snake alive and for other snake another 50 blades of grass is required so in all 100 blades of grass is required for survival of two snakes which makes food for eagles .

  

                        10 blades of grass=1 grasshopper

                         50 blades of grasshopper= 5 grasshopper

                         5 grasshopper= 1 snake

                   10 grasshopper= 2 snake

                 2 snakes = 1 eagle

Eagle requires 2 snakes for its survival and 2 snakes require 10 grasshoppers for their survival and 10 grasshoppers requires 100 blades of grass

3) 2800 blades of grass

If one eagle requires 100 blades of grass one day it requires 700 blades of grass for one week (7 days)and for a family of four eagles they requires 2800 blades of grass.

                                    =700x 4 (eagle)= 2800 blades of grass.

Cricel all of the words

From bottom to top

1) Grass=Producer, prey, Autotroph

Grass is the producers which can produces it own food hence called as autotroph. It acts as prey for many insects like grasshoppers which feed upon the grass. They absorb sunlight and produce food hence called as producers.

2) Grasshopper=Prey, Predator, heterotoph, consumer

Grasshopper feed on grass hence called as consumer, they can also be called as predator feeding on primary producers. They are dependent on the primary producers for food hence called as heterotoph. They also act as food for the next level organism like snakes hence they also acts as prey.

3) Snakes=Predator ,prey, consumer, heterotoph,

Snakes feed on grasshoppers hence called as predators or consumers .They cannot food hence termed as heterotoph while they are consume by the higher level organism like eagles hence they can be called as prey.

4) Eagle=Predator, consumer, heterotoph

Eagles are classified as predator or consumers feeding on snakes. Eagles cannot make their food and depends on lower tropic level organisms hence they are heterotoph.