Energy Systems, Flows, Pyramids and other Small Topics

Question 1

What is a term used to describe the relationships between the members of a community in an ecosystem?

Answer 1

Food Chain or Food Web

Question 2

What is each stage in a food chain known as?

Answer 2

A trophic level

Question 3

What do food chains typically start with?

Answer 3

Photosynthetic producers because they extract energy and matter from the sun and other abiotic environmental factors

Question 4

What are the 3 kinds of ecological pyramids?

Answer 4

• Numbers
• Biomass
• Energy

Question 5

What shape are pyramids of numbers?

Answer 5

Can be any shape depending on the size of the organism on each trophic level. Traingle, inverted triangle, middle widest, etc.

Question 6

What is biomass?

Answer 6

The dry mass of an organism

Question 7

What shape are pyramids of biomass?

Answer 7

Typically pyramid/triangle shaped. Usually cannot be inverted because you can’t weigh more than you eat, but sometimes inverted in aquatic ecosystems for a certain month where growth is rapid and seasonal

Question 8

How much biomass is typically passed from one trophic level to the next?

Answer 8

10%

Question 9

Why is energy/matter lost as you go up the trophic levels?

Answer 9

• Matter is lost as CO2 from Respiration
• Uneaten or indigestible parts
• Waste, e.g. Faeces and Urine
• Movement
• Thermogenesis

Question 10

What are pyramids of energy?

Answer 10

Pyramids which represent the flow of energy in a given time. They are always very shallow since energy transfer between trophic levels is very inefficient (typically 1%)

Question 11

Compare and contrast Matter and Energy (4 Points)

Answer 11

• Matter is kilograms, Energy is joules
• Matter is 3 states, solid, liquid or gas. Energy comes in many forms
• Neither energy or matter can be destroyed
• Level of Matter on Earth is constant, Energy is ‘roughly’ constant but can enter and leave

Question 12

Why are food chains so short?

Answer 12

They tend to be 3-4 levels because too much energy is lost at each stage to sustain more levels, which is why there are fewer at the top than bottom

Question 13

Why is it more energy efficient to be vegetarian

Answer 13

Plants are lower on the food chain so less energy is lost in the making of it than meat which loses energy at multiple stages

Question 14

What is bio-accumulation?

Answer 14

The accumulation of substances such as pesticides in an organism, which occurs when an organism absorbs a toxic substance at a higher rate than at which it is lost

Question 15

How is energy lost going from the sun to producers?

Answer 15

• Light passes through the leaves and misses the chloroplasts
• Light is reflected off the leaves
• Light is reflected by atmosphere and clouds
• Limiting factors of photosyntheiss

Question 16

What percentage of light energy of light energy becomes biomass in producers?

Answer 16

2%

Question 17

What are the advantages of intensive farming?

Answer 17

• Cheaper food because higher yield
• Higher yield for less space
• Selective breeding for higher productivity
• Selected diet
• Less Movement, Warmer and Safe from Predators

Question 18

What are the disadvantages of intensive farming?

Answer 18

• Quality of food
• Spread of Disease
• Antibiotic resistance
• Cruel to Animals
• Potential overheating

Question 19

Pros and cons of herbicides to improve farming productivity

Answer 19

Kills weeds stealing minerals from the main crop but reduces species diversity

Question 20

Pros and cons of pesticides to improve farming productivity

Answer 20

Decreases loss of crop due to pests, increases productivity but upsets the food chain involving the pests

Question 21

Pros and cons of using larger fields to improve farming productivity

Answer 21

Removing non productive things like hedgerows means more crop per unit land, but removes habitats in hedgerows

Question 22

Pros and cons of selective breeding?

Answer 22

Increases productivity, but decreases genetic diversity so less likely to survive change in environment

Question 23

Pros and cons of monoculture

Answer 23

increases productivity but allows pests to spread easily

Question 24

List things that can be done to improve farm productivity

Answer 24

• Fertilisers
• Herbicides
• Pesticides
• Large Fields
• Mechanisation
• Selective Breeding
• Green House
• Monoculture

Question 25

What is a pest?

Answer 25

Any organism which damages crops

Question 26

What are the two kinds of pest control?

Answer 26

Biological and Chemical

Question 27

What is biological pest control?

Answer 27

Introduction of another organism to keep the number of pests down below the economic threshold

Question 28

What must be taken into account when choosing a biological control?

Answer 28

• Attacks only the pest and nothing else
• Will not become a pest itself due to lack of predators
• Can survive in the new environment
• Does not carry disease

Question 29

What is Eutrophication?

Answer 29

Excessive richness of nutrients in a lake or body of water due to run-off from land which causes dense growth of plant life

Question 30

What is the problem of eutrophication?

Answer 30

Buildup of algae on water surface so no light can reach plants so no photosynthesis can occur under the water so plants die and oxygen is depleted. Decomposers break down dead plants so oxygen depletes more. Ecosystem dies.

Question 31

What are the reasons for Conservation?

Answer 31

• Ethical
• Economical
• Cultural/Aesthetic