Crown of Thorns starfish I

This task is about what diagrams of food chains can and/or cannot tell you about the organisms involved. 
Scientists have observed the Crown of Thorns starfish eating hard coral and being eaten by fish such as wrasse, puffer fish and the triton trumpet shell fish.
They represent this feeding relationship in food chains as shown below.
COT-II-food-chain-400h.png
 

Question

The order of the organisms and the direction of the arrows are agreed upon by scientists to describe the feeding relationship [what eats what to obtain nutrition] between the species in a biotic community.
 

Choose which idea below is being represented by the direction of the arrows?

    • The energy transferred from one species to another.

    • The nutrients the predators obtain. 

    • The producer species. 

    • How much energy the predators need. 

Question

Choose which 2 things the Crown of Thorns food chain tells us about the hard coral?

    • Hard coral is eaten by the Crown of Thorns starfish.

    • Hard coral is eaten by zooplankton.

    • Pufferfish are a predator of hard coral.

    • Hard coral eats zooplankton.

Question

Feeding relationships can be very complex. Food chain diagrams tell just a little part of the food relationship story.
 
 
Choose which 2 things the Crown of Thorns food chain does not tell us about the Crown of Thorns predators?

    • Wrasse, pufferfish and triton trumpet shellfish are predators of Crown of Thorn starfish.

    • Wrasse, pufferfish and triton trumpet shellfish each eat the same amount of Crown of Thorn starfish.

    • Wrasse, pufferfish and triton trumpet shellfish only eat Crown of Thorn starfish. 

    • Wrasse, pufferfish and triton trumpet shellfish are not predators of hard coral.

Question 1Change answer

Knowing about the interactions of organisms in a food chain helps scientists predict what might happen when there is a change in the environment.
From the information in the Crown of Thorns food chain, for each of the following three statements choose whether you think scientists could confidently predict an outcome without gathering further information.
1. Overfishing of the triton trumpet shellfish will affect the COT starfish population 
confidently predictit dependscan't predict
2. A phytoplankton bloom [increase in the phytoplankton population] will affect the zooplankton population 
confidently predictit dependscan't predict
3. An increase in COT starfish will affect the hard coral population of a coral reef 
confidently predictit dependscan't predict

Question

Choose one of your answers and explain why you think this.

    • Overfishing of the triton trumpet shellfish will affect the COT starfish population

    • A phytoplankton bloom [increase in the phytoplankton population] will affect the zooplankton population

    • An increase in COT starfish will affect the hard coral population of a coral reef 

Explanation