B17. Food chains/webs and nutrient cycles

Question 1

What do food chains show?

Answer 1

Food chains show the transfer of energy through a food chain.

Question 2

What type of organism is always the start of a food chain.

Answer 2

All food chains begin with an organism that can photosynthesise (i.e. a green plant, algae or cyanobacteria) which makes food (glucose) by photosynthesis.

Question 3

What is the name given to each level of the food chain?

Answer 3

Each level of a food chain is called a trophic level.

Question 4

How do decomposers form part of some food chains?

Answer 4

Decomposers are bacteria and fungi which break down dead plant and animal matter.
Decomposers secrete enzymes onto the surface of the dead organisms
The matter is broken down into soluble food molecules, which are then absorbed into the microorganism by diffusion.

Question 5

What type of consumer is the organism that eats the producer?

Answer 5

Primary consumer

Question 6

What type of consumer is the organism that eats the primary consumer?

Answer 6

Secondary consumer

Question 7

What type of consumer is the organism that eats the secondary consumer?

Answer 7

Tertiary consumer

Question 8

What are apex predators and give an example.

Answer 8

Apex predators are carnivores with no predators. You will find them at the top of a food chain e.g. killer whale

Question 9

Distinguish between predators and prey

Answer 9

Apredatoris an animal that hunts and eats other animals, and thepreyis the animal that gets eaten by the predator.

Question 10

List some key adaptations of good predators

Answer 10

Camouflage, speed, agility, sharp claws and teeth, stealth, enhanced senses, monocular vision etc.

Question 11

List some key adaptations of prey animals

Answer 11

Camouflage, warning colouration, mimicry, speed, agility, binocular vision, protective body armor, group defensive, chemical defences

Question 12

Describe the pattern of a predator-prey graph

Answer 12

In a stable community the numbers of predators and
prey rise and fall in cycles.
This is called a cyclical pattern

Question 13

What is the difference between a food chain and food web?

Answer 13

Afood webis a network of interconnected food chains.
They also showinterdependence- how the change in one population can affect others within the food web.

Question 14

Describe simply what the water cycle is.

Answer 14

The water cycle is the continuous movement of water between the atmosphere, land, oceans, and living organisms.

Question 15

List the main stages of the water cycle

Answer 15

Evaporation, condensation, (cooling), precipitation, percolation, transpiration & respiration

Question 16

Describe the process of evaporation in the water cycle.

Answer 16

Evaporation is the process by which water from bodies of water, such as rivers, lakes, and oceans, is heated by the sun and changes from liquid to water vapor, rising into the atmosphere.

Question 17

What is condensation in the context of the water cycle?

Answer 17

Condensation is the process by which water vapor in the atmosphere cools and changes back into liquid water, forming clouds or dew.

Question 18

Explain how precipitation occurs in the water cycle.

Answer 18

Precipitation is the release of moisture from clouds in the form of rain, snow, sleet, or hail, returning water from the atmosphere to the Earth’s surface.

Question 19

What role do plants play in the water cycle?

Answer 19

Plants absorb water from the soil through their roots and release water vapor through a process called transpiration, contributing to the moisture in the atmosphere.

Question 20

How does human activity impact the water cycle?

Answer 20

Human activities such as deforestation, urbanization, and pollution can alter the natural flow of the water cycle by affecting evaporation, transpiration, runoff, and groundwater recharge.

Question 21

Discuss the importance of the water cycle for ecosystems and human society.

Answer 21

The water cycle is vital for maintaining ecosystems, regulating climate, supporting agriculture, and providing drinking water for human populations.

Question 22

What is the carbon cycle?

Answer 22

The carbon cycle is the continuous movement of carbon between the atmosphere, oceans, land, and living organisms.

Question 23

Describe the process of photosynthesis in the carbon cycle.

Answer 23

Photosynthesis is the process by which green plants and algae use carbon dioxide from the atmosphere, along with water and sunlight, to produce glucose and oxygen.

Question 24

How is carbon dioxide released back to the atmosphere in the carbon cycle?

Answer 24

Carbon dioxide is released into the atmosphere through cellular respiration by living organisms, decomposition of organic matter, and combustion of fossil fuels.

Question 25

What role do decomposers play in the carbon cycle?

Answer 25

Decomposers break down dead organic matter, such as plant and animal remains, releasing carbon dioxide back into the atmosphere through the process of decomposition.

Question 26

Explain the process of combustion in the carbon cycle.

Answer 26

Combustion is the chemical reaction that occurs when fossil fuels, such as coal, oil, and natural gas, are burned for energy, releasing carbon dioxide into the atmosphere.

Question 27

Name the processes that take IN carbon from the atmosphere

Answer 27

• Photosynthesis
• Eating

Question 28

How does the ocean contribute to the carbon cycle?

Answer 28

The ocean absorbs carbon dioxide from the atmosphere, acting as a carbon sink. Carbon dioxide dissolves in seawater and is used by marine organisms for photosynthesis.

Question 29

How does deforestation impact the carbon cycle?

Answer 29

Deforestation reduces the number of trees available to absorb carbon dioxide through photosynthesis. This can lead to an increase in atmospheric carbon dioxide levels and contribute to climate change.

Question 30

What is decomposition?

Answer 30

Decomposition is the breakdown of organic matter by microorganisms into simpler substances.

Question 31

Why is decomposition important in ecosystems?

Answer 31

It is important in ecosystems because it recycles nutrients, releasing them back into the environment for use by other organisms.

Question 32

Describe the factors that influence the rate of decomposition.

Answer 32

Factors influencing decomposition include temperature, moisture, oxygen availability, pH

Question 33

Explain how temperature affects the rate of decomposition.

Answer 33

Warmer temperatures generally increase the rate of decomposition by speeding up the activity of decomposer organisms, while colder temperatures slow down decomposition.

Question 34

Discuss the role of moisture in decomposition.

Answer 34

Moisture is essential for decomposition because it allows microorganisms to carry out metabolic processes. Excess moisture can lead to anaerobic conditions, while dry conditions can inhibit decomposition.

Question 35

Explain the importance of oxygen availability in decomposition.

Answer 35

Decomposition is aerobic, meaning it requires oxygen. Adequate oxygen levels promote the activity of aerobic decomposers, while anaerobic conditions can slow down decomposition and produce byproducts like methane.

Question 36

Describe the relationship between pH and decomposition.

Answer 36

Decomposer organisms have optimal pH ranges for activity, and extremes in pH can inhibit their function. Neutral to slightly acidic pH ranges are generally conducive to decomposition.

Question 37

Discuss the potential impact of human activities on the rate of decomposition in ecosystems.

Answer 37

Human activities such as deforestation, pollution, and the use of chemical fertilizers can disrupt decomposition processes by altering soil conditions, reducing biodiversity, and introducing toxins that inhibit decomposer organisms.