4.7- Energy Efficiency

The diagram is a pyramid of energy:

• Of the 100% of producer, only 10% makes it to the next level in the primary consumer
• Of the 100% of producer, only 1% makes it to the next level in the secondary consumer

Question: What are the causes of the losses that we are seeing?

Simple food chain:

1. Producer (grass)- 100 kJ eaten by herbivore
2. Primary consumer (mouse)- only 10kJ of the original will become part of the mouse's body and tissues
• This is because they have to find their own food and they carry out the process of respiration
• Not all of the 100kJ of energy is actually available to the mouse:
• Mice cannot digest cellulose so the plant cell wall cannot be digested and the energy is lost in the form of faeces(undigested material). So, 90kJ is lost through respiration and undigested food
3. Secondary consumer (Owl)- only be able to assimilate 1kJ
• The losses to the owl are respiration. Energy required for:
• Movement
• Flight
• Digestion 
• Not all of the mouse is digested by the owl and so some is lost as faeces

All organisms will finally die and are broken down by micro-organisms called decomposers.

4.6- Energy and substances in food chains

1. Producer converts light energy into chemical energy
2. This chemical energy takes the form of:
• Organic molecules
• Carbohydrates 
• Proteins 
• Lipids
3. These molecules are all food to consumers in the food chain and contain bonds such as:
• C-H
• C-O
• C-C
• O-H
• C-N
• These bonds all represent energy
• CHON (substances/matter) contain energy

• The impala consumes substances for:
• Respiration, growth and life processes 
• When the leopard eats the Impala, these molecules are re-organised into leopard form

4.5c)- Pyramids

Three types of pyramids covered:

• Pyramids of number
• Pyramids of biomass
• Pyramids of energy transfer

1. Pyramids of number
• Illustrates the number of organisms at each trophic level
• Some problems are:
• Not effective at showing energy transfer
• Effective but have some problems
2. Pyramids of biomass
• Bio= 'Living'
• Mass='g/kg'
• Based on dry mass
• Measured in kg/area (km squared)
• Hard to carry out experiments to find out dry biomass
3. Pyramids of energy transfer
• Show the movement of energy from one trophic to the next
• Cannot be inverted (Advantage)
• The reduction at each trophic level shows the measure off efficiency
• Unit of energy- J/kJ
• Unit of area- m squared
• Unit of time- minutes/seconds/years
• Problem- time consuming

• Pyramid of number> biomass> energy

4.5b)- Food Webs

Food webs can show organisms feeding at different trophic levels.

Feeding at different trophic levels:

• Organisms can have multiple predators
• They could be feeding on different prey
• This results in the food chains becoming linked

4.5a)- Food Chain

Food chain links together the:
 Producer--- Primary Consumer--- Secondary Consumer--- Tertiary consumer

In a food chain you cannot show an organism:

• being an omnivore
• feeding at 2 trophic levels

Food chains show the flow of matter and energy

4.4- Trophic Levels

Trophic = Feed

• Producer turns light energy into chemical energy
• Primary consumer changes the form of the chemical energy 
• Secondary consumer also changes the form of the chemical energy
• Tertiary consumers change chemical energy to chemical enrgy

• All organisms die and are broken down by decomposers (fungi and bacteria)
• Decomposers are important in recycling of molecules
• They often break down the complex molecules into nitrates and phosphates

4.3- Quadrates Samples

Describe the use of quadrats as a technique for sampling the distribution of organisms in their habitats

-Use quadrats to sample the population
Samples:
-Random
-Representative (Large), the bigger the better
-Random numbers (x,y co-ordinates), can be generated online
-Count the population in the square of the random x,y co-ordinates
-10% of the actual area

No. of eg. daises per meter squared= no.of daises divided by no. of quadrats

4.2- Quadrats

Recall the use of Quadrats to estimate the population size of an organism in two different areas:
Quadrating:
-Count the number of individuals in the population
-Quadrat is used to sample the area and count the number of individuals in the area
-This would be repeated a number of times to gain an estimate of the population size

Quadrats are a method of sampling different location so that populations can be compared in the two different locations

4.1- Ecosystems

Ecosystem-- community of organisms which in a particular habitat
Community-- different populations of different species interacting within that habitat
Population-- No. of individuals of a particular species
Species-- Organisms that reproduce to give fertile offspring
Habitat (abiotic factors, non-biological):
- Cycle of daylight
-Temperature
-Rainfall
-Humidity
-Slope

Plants

Examples of plants around the school:

Some photos taken from http://danielscienceblogg.blogspot.com/