6.5.1.-6.5.2(Energy transfer through an ecosystem)

Define habitat

• The place where an organism lives

Define population

All organisms of one species in a habitat

Define a Niche

• The functional role an organism plays within an ecosystem

Define what is meant by a decomposer

An organism that breaks down dead or undigested organic material

What is meant by a trophic level

• A stage in the food chain occupied by a particular group of organisms

Define what is meant by autotrophs

• Capture energy and store it as organic molecules - producers

Define what an heterotroph is

• Obtain organic material from autotrophs - consumers

Define an ecosystem

• An ecosystem is a community of organisms and their physical environment

Define biotic and abiotic

• Biotic - living organisms in an ecosystem

• Abiotic - Non-living organisms in an ecosystem

Define what is meant an by a Biotic and Abiotic factor(not complete)

• A biotic factor is anything that is living which influences an ecosystem

• An Abiotic factor is anything that is non-living influences the an ecosystem

Give 5 examples of Biotic factors in an ecosystem

• Predation

• Competition for space, food, water, light

• Disease

• Camouflage

• Mimicry

Give 4 examples of Abiotic factors in an ecosystem(not complete)

• pH of soil/water

• Rain fall

• Temperature

• Humidity

State the 3 types of change in ecosystem population size

• Cyclic changes

• Directional changes

• Erratic changes

Briefly describe the 3 types of changes in population size

1. Cyclic:

   • Changes which repeat themselves in rhythm

2. Directional:

   • Changes which go in one direction and last longer than the lifetime of organisms within an ecosystem

3. Erratic:

   • Changes which have no rhythm and no constant direction

What is the unit for transfer of energy at each trophic level

• KJ m-2 yr-1

Describe how energy moves through an ecosystem

• Energy moves through trophic levels when organisms eat organisms in the trophic levels below

• Not all energy is passed on, some is lost as heat during the process of respiration and othe rprocesses

Explain why not all sunlight energy is transferred into plants

• 60% of energy will not e transferred to the plant if:

  • Wrong wavelength reaches the plant

  • The wavelength is reflected

  • If the wave passes through the leaf

  • if the wave hits non-photosynthesising parts of the plant

What is meant by gross primary productivity (GPP) of a plant

• The rate at which light energy is captured and stored within sugar molecules during photosynthesis(energy captured per unit area per unit time

What will the GGP of a plant used for

• Energy will be used for respiration, metabolic processes and growth

How to calculate Net productivity

• Gross productivity - Respiratory loss

state how much biomass in food is tranferred between each trophic level

• At most 10%

Explain why not all biomass is transferred between each trophic level

• Not every part of the organism is eaten

• Not every part is digestible so will get egested as faeces

• Energy is used for movement

• Excess amino acids will be excreted as urine

• Energy is lost as heat during respiration

What is the equation for calculating trophic efficiency

• (Energy passed onto the next level/energy received from previous level)x100

• (Net productivity/Net productivity of previous level)x100