Unit 3 Lesson 4: Trophic Levels

Question 1

There are many ways ecosystems can be disrupted. Provide some examples.

Answer 1

There are many ways ecosystems can be disrupted. An iceberg can break off of a glacier. A heavy wind could blow down some trees in a forest. An oil spill could pollute the water surrounding a wildlife refuge.

Question 2

What does an ecosystem’s sustainability mean

Answer 2

An ecosystem’s sustainability is how effective it is at meeting the needs of the organisms that live in it.

Question 3

What happens if the sustainabilty of an ecosystem decresases

Answer 3

If the sustainability of an ecosystem decerases, this means it cannot continue to support the entire ecosystem. Each of these disturbances can have various effects on biodiversity, the total number and types of organisms in an area.

Question 4

Ecosystems are composed of

Answer 4

trophic levels

Question 5

trophic levels

Answer 5

the level at which an organism is found on the food chain;

Question 6

What is the trophic level of an organism

Answer 6

The trophic level of an organism is the number of levels that organism is away from the start of the food chain or web.

Question 7

1.

What is the primary source for ecosystems

Answer 7

The primary source of energy for ecosystems is the sun (with some exceptions such as deep-sea ecosystems).

Question 8

Producers, such as plants and some algae, are at what level of the food chain

Answer 8

Producers, such as plants and some algae, are at the first trophic level because they use the energy of the sun to convert water and carbon dioxide into a food source, or glucose. Producers are also known as autotrophs, or self-feeders, and they use the process of photosynthesis for this conversion.

Question 9

What are the reamining trophic levels mad eup of

Answer 9

The remaining trophic levels are made up of consumers, or heterotrophs, which cannot produce their own food. Consumers rely on other organisms in order to obtain their nutrition. Heterotrophs are comprised of herbivores (organisms that only eat producers), carnivores (organisms that only eat other consumers), or omnivores, that eat both producers and consumers.

Question 10

The second trophic level consists of herbivores or omnivores, that gain energy by eating producers. This level of consumer is known as

Answer 10

primary consumers

Question 11

primary consumers

Answer 11

an organism that feeds on producers such as plants. A primary consumer is also known as an herbivore.

Question 12

The third trophic level is made up of both carnivores, and omnivores, which are known as

Answer 12

secondary consumers

Question 13

The top trophic level consists of mostly carnivores that rely on secondary consumers for energy and are known as

Answer 13

tertiary consumers

Question 14

secondary consumer

Answer 14

an organism that feeds on primary consumers, or herbivores

Question 15

tertiary (third) consumer

Answer 15

a top-level consumer that is a carnivore and feeds on secondary consumers

Question 16

Is the top trophic level orgnaims an omivore or carinvore

Answer 16

The top trophic levels can be an omnivore but the further away from the start of the food chain or web, the more likely that organism is a carnivore.

Question 17

quaternary consumers

Answer 17

There is sometimes another level known as quaternary consumers, but most ecosystems do not contain enough energy to support this level.

Question 18

Why is only a small amount of passed frmo the lower levels to higher levels

Answer 18

. Since the animal used most of the matter and energy for itself, only a small amount can be passed from the lower trophic levels to the higher levels.

Question 19

The amount of energy at each trophic level ? up the food chain.

Answer 19

The amount of energy at each trophic level decreases up the food chain.

Question 20

Why is there fewer animals at the top levels than the bottom

Answer 20

Because there is only a small amount of matter and energy being passed up the food chain, there are fewer animals at the top levels than the bottom.

Question 20

Energy is measured in

Answer 20

kilocalories or Kcal

Question 21

Foods with lower Kcal have a ? amount of energy.

Answer 21

Foods with lower Kcal have a smaller amount of energy.

Question 22

It is estimated that only about ?% of the energy stored as biomass in one trophic level is transferred to the next trophic level’s biomass storage.

Answer 22

10

Question 23

The other 90% is used by the consumer for life processes such as

Answer 23

movement and breaking down nutrients or given off as heat energy.

Question 24

At each trophic level, energy that is passed on continues to lessen by approximately 90%. What does this explain

Answer 24

This also explains why there are fewer tertiary consumers than producers because there isn’t enough energy to sustain a large number at the top.

Question 25

Why are producers always the first trophic level in an ecosystem?

Answer 25

Producers are the first level because they have a direct relationship with the primary source of energy. The primary source of energy almost always is radiant energy from the sun. The producers are able to convert light energy into chemical energy through photosynthesis.

Question 26

If stargrass is the producer in a food chain and has a total biomass storage of 150,000 Kcal of energy, how much energy will each of the following trophic levels have available? zebra (primary consumer) cheetah (secondary consumer) lion (tertiary consumer) Answer

Answer 26

zebra (primary consumer) - 15,000 Kcal of energy cheetah (secondary consumer) - 1,500 Kcal of energy lion (tertiary consumer) - 150 Kcal of energy

Question 27

A trophic level indicates which of the following? how much energy an organism produces how many producers grow each day the level where an organism is found in the food chain how much biomass is produced

Answer 27

The best answer is C. This is the definition of a trophic level.

Question 28

Decomposers break down dead and decaying organisms and return their nutrients back into the ecosystem. What role would decomposers play in cycling matter within an ecosystem?

Answer 28

After an organism dies the matter will decompose into nutrients and mix into the soil. Plants and animals will use the nutrients from the soil to grow and reproduce. When those plants and animals die the cycle will repeat.

Question 29

Explain how autotrophs obtain their energy from an ecosystem.

Answer 29

Autotrophs are producers and obtain their energy from the sun. They use this energy along with carbon dioxide and water to produce glucose.

Question 30

Explain what happens to the energy an organism does not use.

Answer 30

Energy not used for cellular processes is released as heat into the ecosystem. Energy decreases as you move up trophic levels. Only about 10% of the biomass energy is transferred from one trophic level to the next.

Question 31

keystone species

Answer 31

the organisms an ecosystem heavily depends on to keep its balance

Question 32

If keystone species are threatened the ecosystem can change drastically. What owuld happen to primary consumers

Answer 32

When producers are removed from an ecosystem at a fast rate there is less food for primary consumers, such as insects and small rodent species.

Question 33

When producers are removed from an ecosystem at a fast rate there is less food for primary consumers, such as insects and small rodent species. How does this affect secondary and higher levels

Answer 33

This decreases the amount of food available for the secondary consumers and the higher trophic levels.

Question 34

When producers are removed from an ecosystem at a fast rate there is less food for primary consumers, such as insects and small rodent species. This decreases the amount of food available for the secondary consumers and the higher trophic levels. When this takes place, it is known as a

Answer 34

population crash