B17 - Organisising An Ecoystem (Y11 - Spring 2)

Question 1

🟢 How can Feeding Relationships within a Community represented

Answer 1

Feeding relationships within a community can be represented by food chains. All food chains begin with a producer which synthesises molecules. This is usually a green plant or alga which makes glucose by photosynthesis.

Question 2

🟢 What are Food Chains And What Orders Are They In

Answer 2

• Each stage in the food chain is called a trophic level, the arrows represent a flow of energy and matter through the food chain.
• A food chain will always start with a photosynthetic producer, e.g green plants, algae, plankton, e.c.t. They are capable of producing organic compounds from inorganic compounds
• All other organisms are consumers, i.e they gain their energy and matter through eating other organisms.

Question 3

🟢 What’s Eaten by What in Food Chains

Answer 3

Producers are eaten by primary consumers, which in turn may be eaten by secondary consumers and then tertiary consumers.

Question 4

🟢 Why are Food Chains Always Relatively Short

Answer 4

Food chains have poor energy efficiency which means energy losses take place at each stage, which is why there are so little food chains that span over 6 or 7 organisms (as the energy being passed down becomes less and less)

Question 5

🟢 How do the Number of Predators Rise and Fall in Linked Cycles?

Answer 5

In a stable community the numbers of predators and prey rise and fall in linked cycles.

• If there is plenty of food avaliable, the prey animals grow and reproduce successfully, so numbers increase.
• As prey animal numbers go up, there is plenty of food availabke for the predators, so predators can reproduce successfully and predator numbers increase.
• The high number of predators eat a larger
  proportion of the prey animals, so prey numbers fall.
• With fewer prey animals, there is less food for the predators, so they are less successful and predator numbers fall.
• With the reduction in predators, and the good
  supply that results from fewer animals, prey numbers go up again and the cycle repeats itself.

(This is only true in a stable community)

Question 6

🟢 What are Predators and What are Prey

Answer 6

Consumers that kill and eat other animals are predators, and those eaten are prey.

Question 7

🟢 What Is a Stable Community

Answer 7

A stable community is one where all of the biotic and abiotic factors are in balance.

Question 8

🟢 How Can a Predator-Prey Cycles Change?

Answer 8

The cycles would change if something changed in the community, for example a drought happened, or a new predator arrived, then predator prey cycle would start to change.

Question 9

🟢 Explain what is happening after the Predatir population is decreasing in a predator-prey cycle

Answer 9

The prey population is starting to increase because the predator population is low. This means that more of the prey population can survive and reproduce, as their birth rate will be faster than their death rate, allowing the prey population to grow again..

Question 10

🟢 What Does Anaerobic Decay Produce

Answer 10

Anaerobic decay produces methane gas. Biogas generators can be used to produce methane gas as a fuel.

Question 11

🟢 What Are The 3 Conditions Needed For Decay

Answer 11

• Temperature
• Moisture
• Oxygen

Question 12

🟢 What Temperature Conditions are Needed for Decomposition

Answer 12

The speed at which things decay depends partly on the temperature. Chemical reactions in microorgnaims, like those in most living things, work faster in warm conditions. They slow down and might even stop if the conditions are too cold. Decay also stops if it gets too hot, as the enzymes in the decomposers are denatured and/or kill the microbes.

Question 13

🟢 What Moisture Conditions are Needed for Decomposition

Answer 13

Most microorganisms grow faster in moist conditions. The moisture makes it easier for them to digest their food and also prevents them from drying out. So the decay of dead plants and animals - as well as leaves and dung - takes place far more rapidly in warm, moist conditions than does in cold, dry ones.

Question 14

🟢 What Oxygen Conditions are Needed for Decomposition

Answer 14

Although some microorganisms are anaerobic, most decomposers respire aerobically. This means they need oxygen to break down food and transfer energy, grow, and reproduce. This is why decay takes place more rapidly in aerobic conditions when there is plenty of oxygen avaliable.

Question 15

🟢 What Do Gardeners Use Decay For?

Answer 15

Gardeners and farmers try to provide optimum conditions for rapid decay of waste biological material. The compost produced is used as a natural fertiliser for growing garden plants or crops.

Question 16

🟢 What does Anaerobic Decay Produce?

Answer 16

Anaerobic decay produces methane gas. Biogas generators can be used to produce methane gas as a fuel.

Question 17

🟢 How does Decay make Compost

Answer 17

We can use the process of decay to make compost. Decomposers will break down our waste kitchen and garden plant material to make a brown, crumbly substance. The compost is full of nutrients released by the decomposers. This process takes from a few months to over a year. The compost forms a good, natural fertiliser.

Question 18

🟢 What is the point/use of Compost

Answer 18

Compost, or well-rotted manure provides fertiliser for the soil, returning valuabke minerals, and also improving soil structure and water retention.

Question 19

🟢 Does the way Compost is made differ between gardens and farm, and can Compost be made with and/or without oxygen?

Answer 19

Whether done in the garden, or on a large farm, the principles of composting are the same. Compost can be made with or without oxygen

Question 20

🟢 What Happens if Compost is Made With Oxygen

Answer 20

If the microorganisms have oxygen, they respire aerobically and transfer energy to their surroundings, killing off weed seeds and speeding up the process.

(The warmer the compost mixture, the faster the compost will be made (up to about 70° when decomposition stops). The decay process is also faster in moist conditions that in dry ones.)

Question 21

🟢 What Happens if Compost is Made Without Oxygen

Answer 21

Without oxygen, the process does not cause a rise in temperature and is slower.

(The warmer the compost mixture, the faster the compost will be made (up to about 70° when decomposition stops). The decay process is also faster in moist conditions that in dry ones.)

Question 22

🟢 What happens when Bacteria decompose waste Material in Anaerobic conditions?

Answer 22

When bacteria decompose waste material in anaerobic conditions they produce methane. Methane is a flammable gas which can be used as fuel for vehicles.

Question 23

🟢 What are Biogas Generators and How Do They Work

Answer 23

Plant and/or animal waste is put into special vessels known as biogas generators and in anaerobic conditions decomposers produce methane gas for use as a fuel. The bacteria involved in methane production work best at a temperature of around 30°C, so biogas generators tend to work best in hot climates. However, the process transfers energy to the surroundings because the reactions are exothermic. This means that if you heat the mixture at the beginning to start things off, and have your generator well insulated to prevent cooling, biogas generators will work anywhere.

Question 24

🟢 How can we use the Process of Anaerobic Decay to Provide us with Fuel?

Answer 24

We can use the process of anaerobic decay or decomposition to provide us with fuel. Together the methane and carbon dioxide produced are called biogas. This is a source of renewable energy.

Question 25

🟢 What are Biogas Generators

Answer 25

Biogas generators are large vessels in which animal waste or specially grown crops such as maize are allowed to anaerobically digest. If domestic waste is used as a source of methane, this also reduces the volume of domestic waste added to landfill sites.

Question 26

🟢 What Happens in Material Cycling

Answer 26

All materials in the living world are recycled to provide the building blocks for future organisms.

Question 27

🟢 What Does The Water Cycle Do?

Answer 27

The water cycle provides fresh water for plants and animals on land before draining into the seas. Water is continuously evaporated and precipitated.

Question 28

🟢 What Happens In The Water Cycle

Answer 28

The water cycle provides fresh water for animals and plants on land before draining into the seas and oceans.

Water evaporates constantly from the surface of the land and the rivers, lake, and oceans of the world. It condenses as it rises into the cooler air and forms clouds, where it is then precipatated onto the surface of the Earth as rain, snow, hail, or sleet.

Water passes through the bodies of animals and plants, released during respiration in their lifetime, as well as when organisms decay. Animals also release water in urine, faeces, and swear (in mammals), whilst plants release water into the atmosphere during transpiration.

Every drop of water you drink has been through the bodies of many living organisms before you.

Question 29

🟢 What are the Main Stages Of The Water Cycle

Answer 29

• Condensation
• Precipitation
• Evaporation
• Transpiration
• Respiration

Question 30

🟢 What Processes Remove Carbon Dioxide form the Atmosphere

Answer 30

• Photosynthesis

Question 31

🟢 What Processes Add Carbon Dioxide form the Atmosphere

Answer 31

• Respiration

- Combustion

Question 32

🟢 How does Photosynthesis Remove Carbon Dioxide from the Atmosphere

Answer 32

Green plants and algae remove carbon dioxide for photosynthesis. They use carbon from carbon dioxide to make carbohydrates, proteins, and fats. These make up the biomass of the plants and algae. The carbon is passed on through food chains to animals including primary, secondary, and tertiary consumers.

Question 33

🟢 How does Respiration Add Carbon Dioxide to the Atmosphere

Answer 33

Living organisms respire constantly. They use oxygen to break down glucose, providing energy for their cells. Carbon dioxide, as well as water is produced as a waste product. This is how carbon is returned to the atmosphere

Question 34

🟢 How do Decomposers Add Carbon Dioxide to the Atmosphere

Answer 34

When plants, algae, and animals die, their bodies are broken down by the decomposers (like blowflies, mould, and bacteria) that feed on the dead bodies. Carbon is released into the atmosphere as carbon dioxide as the decomposers respire.

All of the carbon (in the form of carbon dioxide) released by the various living organisms is then avaliable again. It is ready to be taken up by plants and algae in photosynthesis.

Question 35

🟢 How does Combustion Remove Carbon Dioxide to the Atmosphere

Answer 35

Wood from trees contains lots of carbon, locked into the molecules of the plant during photosynthesis over many years. Fossil fuels also contain lots of carbon, which was locked away by photosynthesising organisms millions of years ago.

When. wood and fossil fuels are burnt, carbon dioxide is produced, so we release some of that carbon back into the atmosphere. Huge quantities of fossil fuels are burnt worldwide to power vehicles and generate electricity. Wood is burnt to heat homes and to cook food in many countries.

Question 36

🟢 Word and Chemical Equations for Photosynthesis and Respiration

Answer 36

Photosynthesis:
Carbon Dioxide + Water —> Glucose + Oxygen
6CO2 + 6H2O —> C6H12O6 + 6O2

Respiration:
Glucose + Oxygen —> Carbon Dioxide + Water
C6H12O6 + 6O2 —> 6CO2 + 6H2O

Question 37

🟢 Word Equation for Combustion

Answer 37

Combustion:

Fossil Fuel / Wood + Oxygen —> Carbon Dioxide + Water

Question 38

🟢 What are Decomposers

Answer 38

The decomposers are a group of microorganisms that include bacteria and fungi. They feed on waste droppings and dead organisms.

Question 39

🟢 How Do Microorganisms Start the Process of Decay

Answer 39

Detrivores, such as maggots and some types of worms and beetles often start the process if decay. They eat dead animals and produce waste material. The bacteria and fungi then digest everything - dead animals, plants, and detritus feeders plus their waste. They use some of the nutrients to grow and reproduce and release carbon dioxide, water, and mineral ions as waste products.

Question 40

🟢 What are Bacteria and Fungi Waste Products

Answer 40

They release carbon dioxide, water, and mineral ions as waste products.

Question 41

🟢 How Do Decomposers Return Mineral Ions and Plants absorb them

Answer 41

Decomposers return mineral ions, including nitrates, to the soil. Plants take them up through their roots and use the to make proteins and other chemicals in their cells.

Question 42

🟢 How Does Decay Return Carbon to the Atmosphere

Answer 42

Decay returns carbon to the atmosphere as carbon dioxide that dan be used by producers in photosynthesis.

Question 43

🟢 What Happens in The Carbon Cycle Overview

Answer 43

1. CO2 is removed from the atmosphere by green plants and algae during photosynthesis. The carbon is used to make glucose, which can be turned into carbohydrates, fats and proteins that make up the bodies of the plants and algae
2. When the plants and algae respire, some carbon is returned to the atmosphere as CO2.
3. When the plants and algae are eaten by animals, some carbon becomes part of the fats and proteins in their bodies. The carbon then moves through the food chain.
4. When the animals respire, some carbon is returned to the atmosphere as CO2.
5. When plants, algae and animals die, other animal (called detritus feeders) and microorganisms feed on their remains. When these organisms respire, CO2 is returned to the atmosphere.
6. Animals also produce waste that is broken down by detritus feeders and microorganisms.
7. The combustion (burning) of wood and fossil fuels also releases CO2 back into the air.
8. So the carbon (and energy) is constantly being cycled - from the air, through the chains (via plants, algae and animals, and detritus feeders and microorganisms) and eventually back out into the air.