Bio 13 - Ecosystems Flashcards
What is an ecosystem?
Includes all organisms living in a particular area
What are producers?
Organisms that make their own food
What is biomass?
The chemical energy stored in a plant
How can biomass be measured?
It is measured in terms of the mass of carbon that an organism contains or the dry mass of its tissue per unit area
How can you estimate the amount of chemical energy stored in biomass?
By burning the biomass in a calorimeter. The amount of heat given off tells you how much energy is in it.
What us gross primary production?
Total amount of chemical energy converted from light energy by plants in a given area
How much GPP is lost to the environemnt as heat when plants respire?
50%
What is respiratory loss?
When heat is lost to the environment when the plants respire
What is NPP?
Energy available to the plant for growth and reproduction
What are consumers?
Organisms that obtain their energy by feeding on other organisms rather than using the energy of sunlight directly
What are Saprobionts?
A group of organisms that break down the complex materials in dead organims into simple ones
What is a food chain?
Describes a feeding relationship in which the producers are eaten by primary consumers
What are food webs?
Many food chains linked together to form a food web.
Where do consumers store chemical energy?
In their biomass
How much total energy is lost in the consumers food?
90%
How do consumers get energy?
By ingesting plant material
Why is so much total energy lost in consumers food?
- Not all the food is eaten (roots, bones) so the energy they contain isn’t taken in
- Some of it is indigestible so released as faeces so that chemical energy is lost
- some energy lost through respiration or urine.
What is consumers net production?
The energy left thats stored in the consumers biomass
How do you calculate net production?
Chemical energy in ingested food - (chemical energy lost in faeces or urine+chemical energy lost in respiration)
What are the two different ways to increase the amount of energy that is available for human consumption.
- the energy lost to the other organisms
- the energy lost through respiration
What do insecticides do?
They kill insect pests that eat and damage crops.
What do herbicides do?
Kill weeds.
Why is killing weeds good?
Killing weeds can remove direct competition with the crop for energy from the sun
It can remove the preferred habitat or food source of the insect pests therefore reducing their numbers
What do biological agents do?
Reduce the number of pests so crops lose less energy and biomass
