Lecture Four - Trophic Levels and Energy Flow

Question 1

In the past, sea otters had been hunted to very low numbers in some areas. What do you think happened to the abundance of sea urchins in places where this happened?
A) sea urchins abundance increased
B) sea urchins abundance decreased
C) sea urchins abundance stayed the same

Answer 1

A) sea urchins abundance increased

Question 2

If we increase phytoplankton on the bottom of a food web, what will happen to the abundance of puffins at the top of a food web?
A) the puffins will increase in abundance
B) the puffins will decrease in abundance
C) the puffin abundance will stay the same

Answer 2

A) the puffins will increase in abundance

Question 3

Which of the following statements describes the difference between a food chain and a food web?
A) food webs show how biomagnification occurs, while food chains focus on the transfer of heat
B) food chains follow the passage of food from one type of organism to another, while food chains are composed of many food webs
C) food chains follow the passage of food from one type of organism to another, while food webs are composed of many food chains
D) food chains show relationships among aquatic organisms, while food webs show relationships among terrestrial organisms

Answer 3

C) food chains follow the passage of food from one type of organism to another, while food webs are composed of many food chains

Question 4

According to your textbook, which organisms in a food chain are usually photosynthetic?
A) tertiary consumers
B) producers
C) primary consumers
D) secondary consumers
E) quaternary consumers

Answer 4

B) producers

Question 5

Which of the following types of organisms release heat? Select all that apply:
A) decomposers
B) primary producers
C) primary consumers
D) secondary consumers
E) tertiary consumers

Answer 5

ALL OF THE ABOVE

Question 6

In an ecosystem, top-level predators are rare. Why is this the case?
A) they cannot use chemical energy for maintenance
B) they are eaten by predators in higher trophic levels
C) they cannot convert chemical energy into heat
D) they require many prey organisms from lower trophic levels

Answer 6

D) they require many prey organisms from lower trophic levels

Question 7

Consider the food chain below. When owls are present in high numbers, wheat is present in low numbers. Given this information, how is this food chain controlled?
TOP Owl - Mouse - Insect - Wheat BOTTOM
A) bottom-up control
B) predatory control
C) decomposers control
D) top-down control

Answer 7

D) top-down control

Question 8

Where on Earth is organic nitrogen located? Select all that apply:
A) living organisms
B) the ocean
C) sedimentary rock
D) the air

Answer 8

A) living organisms