C.2 Communities and Ecosystems Flashcards
What is a trophic level?
The position an organism occupies within a feeding sequence
What always occupies the first trophic level in a feeding sequence?
Producers
Why do primary consumers occupy the second trophic level?
Because they feed on producers
What may occupy subsequent trophic levels?
Further consumers
What does a food chain show?
The linear feeding relationships between species in a community?
What do arrows represent in a food chain?
The transfer of energy and matter as one organism is eaten by another
In food chain, what direction does the arrow point in?
The direction of energy flow
What is the first organism in a food chain?
A producer
What follows producers in a food chain?
Consumers
What will most species feeding requirements consist of?
Multiple food chains
In most species feeding requirements what will organisms occupy?
Different trophic levels
What is a food web?
A diagram that shows how food chains are linked together into more complex interrelated feeding relationships
Why is a food web more representative of actual feeding pathways within an ecosystem? (2)
- organisms can have more than one food source
- organisms can have more than one predator
What can organisms do in a food web but not in a food chain?
Occupy more than one trophic level
What does ecological production refer to?
The rate of generation of biomass in an ecosystem
How is ecological production usually expressed?
In units of mass per area per time
What is biomass?
The total dry weight of organic matter in organisms or ecosystems
What is essentially the entirety of all biologically produced organic matter?
Biomass
What is the percentage of energy that is converted into biomass dependent on?
- energy lost as inedible materials
- energy lost via excretion of undigested and unabsorbed materials
- energy is lost as heat from cellular respiration
What is primary production?
The production of chemical energy in organic compounds by producers
What is the main source of energy for primary production?
Sunlight
What is a second source of energy for primary production?
Chemosynthesis
What are the two categories of primary production?
Gross primary production
Net primary production
What is gross primary production?
The amount of chemical energy as biomass that a producer creates in a given length of time