Energy Flow & Human Impact on the Environment

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Energy Flow & Human Impact on the Environment by Mind Map: Energy Flow & Human Impact on the Environment

1. An organism's niche is the role it plays within the community

2. Feeding Relationships

2.1. Producer- Organisms which make their own food

2.1.1. For example, green plants via photosynthesis

2.2. Primary Consumer- Organisms that eat plants only

2.3. Secondary Consumer- Organisms which eat other organisms (primary consumers or secondary consumers)

2.4. Herbivore- A consumer which only eats plants

2.5. Carnivore- A consumer which only eats meat

2.6. Omnivore- A consumer which eats both plants and meat

3. Food Chains

3.1. Example of a Food Chain: Grass ---> Vole ---> Barn Owl

3.2. The arrows in the Food Chain represent the direction of energy flow when one organism eats another

3.3. Food Chains are classed as unstable because if one organism dies off, the whole food chain collapses

4. Food Webs

4.1. Food Webs are classes as stable because if one organism dies off, there are still other options on the food web available

4.2. 3 ways which energy can be lost in a food web: Heat, Movement and Undigested Material

4.3. 10% of the energy is passed onto the next stage in the Food Web (90% is taken up/lost by the previous stage)

5. Ecological Pyramids

5.1. Pyramid of Numbers

5.1.1. Represents the number of organisms at each stage in the food chain

5.1.2. NOT ALWAYS pyramid shape

5.1.2.1. If for example you have a tree as the producer of a food chain only 1 is needed to support the other organisms in the food chain

5.2. Pyramid of Biomass

5.2.1. Represents the mass of organisms at each stage in the food chain

5.2.2. ALWAYS pyramid shape

5.3. Pyramid of Energy

5.3.1. Represents the energy levels at each stage in the food chain

5.3.2. ALWAYS pyramid shape

6. Nitrogen Cycle

6.1. The chemical elements found in all organisms are: Carbon, Hydrogen, Oxygen & Nitrogen

6.2. Plants and animals need nitrogen to make proteins

6.3. Plants get their supply of nitrogen by absorbing it from the soil in the form of nitrates

6.4. Animals get their supply of nitrogen by eating plants and animals containing protein

6.5. Proceses

6.5.1. Decomposition

6.5.1.1. Carried out by Bacteria and Fungi (decomposers)

6.5.1.1.1. What happens during this process: Proteins & Nitrogenous Waste ----> Ammonium Compounds

6.5.2. Nitrification

6.5.2.1. Carried out by Nitrifying Bacteria

6.5.2.1.1. What happens during this process: Ammonium Compounds ---> Nitrites ---> Nitrates

6.5.3. Nitrogen Fixation

6.5.3.1. Carried out by Free Living Soil Bacteria

6.5.3.1.1. What happens during this process: Atmospheric Nitrogen ---> Nitrate

6.5.3.2. Carried out by Bacteria in Root Nodules of Leguminous Plants (e.g. clover)

6.5.3.2.1. What happens during this process: Atmospheric Nitrogen ---> Nitrate

6.5.4. Denitrification

6.5.4.1. Carried out by Denitrifying Bacteria

6.5.4.1.1. What happens during this process: Nitrates ---> Nitrogen Gas (in atmosphere)

7. World Food Demand

7.1. The demand for food is increasing because as the human population size increases, the demand for food also increases

7.2. Starvation occurs in some parts of the world because of Distribution Problems, Conflicts, Political Disputes and Adverse Weather Conditions

8. Intensive Farming

8.1. Monoculture

8.1.1. Monoculture is when you grown one type of crop on a large scale

8.1.1.1. To prepare the land for monoculture, farmers remove the hedgerows between the small fields to make it one big field

8.2. Problems with Intensive Farming

8.2.1. When hedgerows are removed habitats are destroyed therefore decreasing Biodiversity

8.2.2. Pests thrive because of the rich food supply of one crop

8.2.3. If the crop is susceptible to a particular disease or insect, the whole crop could be destroyed, so farmers have to use pesticides

8.2.4. The same nutrients are constantly being taken from the soil, so farmers have to use fertilisers to increase soil fertility

9. Pesticides

9.1. Pesticides are chemicals sprayed onto crops to kill pests

9.2. Types of Pesticides

9.2.1. Insecticides

9.2.1.1. To kill insects

9.2.2. Fungicides

9.2.2.1. To kill fungal pests

9.2.3. Herbicides

9.2.3.1. To kill weeds

9.3. Problems with Pesticides

9.3.1. Some pesticides are not specific therefore they kill other organisms, not just the target pest

9.3.2. Sometimes when organisms eat the pest (e.g. insects), the pesticide is persistent, meaning that it doesn't break down. As they are passed along the food chain toxicity increases and can reach lethal levels. This is known as Bioaccumulation

10. Fertilisers

10.1. Fertilisers are used to add nutrients to the soil, so in turn farmers get an increase in crop production

10.2. Nutrients are constantly being lost from the soil during intensive food production through planting and harvesting (the nutrients are not replaced by the natural process of death and decay e.g. no nitrogen cycle occurs)

10.3. Elements Present in Fertilisers

10.3.1. Nirtogen

10.3.1.1. To make proteins, ATP & Nucleic Acids

10.3.2. Phosphorus

10.3.2.1. For Root Growth

10.3.3. Potassium

10.3.3.1. Potassium for Fruit & Flowers

10.3.4. Magnesium

10.3.4.1. To Make Chlorophyll

10.4. Problems with Fertilisers

10.4.1. Water Systems

10.4.1.1. Fertilisers can leach (wash out) from the soil in fields into freshwater systems

10.4.1.2. The Fertiliser in the water systems increases growth of algae in the water

10.4.1.3. Algae grow and reproduce and form algal bloom (carpet on the surface of the water)

10.4.1.4. Algal blooms block out light to underwater plants, so they die due to lack of photosynthesis

10.4.1.5. Bacteria (decomposers) feed on dead plants, reproduce increasing their numbers and use up the oxygen in the water

10.4.1.6. The decrease in oxygen concentration results in the deaths of many organisms e.g. fish

11. Biological Control

11.1. Biological control is when organisms such as natural predators or parasites are used/introduced to control pest numbers

11.2. Successful example: The Australian Cotton Cushion Scale Insect

11.2.1. The Australian Ladybird Beetle was introduced into California to control the number of Australian Cotton Cushion Scale Insects after they were accidently introduced into California

11.3. Unsuccessful Example: The Hawaiian Cane Toads

11.3.1. The Hawaiian Cane Toads were introduced into Australia to control beetles that feed on sugar cane crops

11.3.1.1. The cane toad successfully ate the sugar can beetles, but any predator that ate the cane toad it was poisoned. This therefore reduced the Biodiversity due to the death of those predators e.g. kangaroo, wallaby, wombat & koala

12. GM Crops

12.1. GM Crops are crops that have had their genes altered by adding in genes from other organisms

12.2. Examples

12.2.1. GM Herbicide Resistant Crops can be sprayed with herbicides without being affected, but the weeds around them will die off, reducing competition

12.2.2. GM Cauliflower

12.2.3. GM Rice (Golden Rice)

12.3. Pros

12.3.1. GM crops can produce a high yeild

12.3.2. Can be altered to withstand drought/floods

12.3.3. Can be altered so that no pesticides are needed therefore, they have less impact on the environment

12.4. Cons

12.4.1. Could result in superbugs or superweeds

12.4.2. Could result in cross contamination between non-GM crops and GM crops

12.4.3. Will be particularly costly and damaging to small scale farmers in the developing world