Topic 5B: Energy transfer and Nutrient cycle- 1. Energy Transfer in Ecosystems Flashcards
Where do plants get their energy from?
The sun
Where do animals get their energy from?
By eating plants or other animals
Definition of ecosystem?
An ecosystem includes all the living organisms living in a particular area and all the non-living (abiotic) conditions.
Definition of producer?
Organisms that makes their own food
What is an example of a producer in a land-based ecosystem?
- Plants e.g. trees, shrubs and grasses.
- They produce their own food through photosynthesis
What is an example of a producer in a aquatic ecosystem?
- Plants e.g. water lilies and watercress
- Algae e.g. seaweeds
- They produce their own food through photosynthesis
What happens during photosynthesis?
- Plants use energy from sunlight and carbon dioxide from the atmosphere in land-based ecosystems or dissolved in water in aquatic ecosystems to make glucose and other sugars.
What are the sugars produced in photosynthesis used in?
- Respiration- to release energy for growth
- Rest of it is used to make other biological molecules e.g. cellulose which make up the cells biomass
Definition of biomass?
Chemical energy stored in a plant
Definition of food chain?
Show simple lines of energy transfer
Food chain example
Producer
I
Primary consumers
I
Secondary consumers
I
Tertiary consumers
Definition of dry mass?
Mass of an organism with the water removed
How can biomass be measured?
- Mass of carbon that an organism contains
- Dry mass of it’s tissue per unit area
Why is dry mass used as a measure of biomass rather than wet mass?
To eliminate the problem of variability due to water content as it varies
How is dry biomass estimated?
- A sample of the organism is dried in an oven at a low temperature
- Sample is weighed at regular intervals
- Once the mass becomes constant, this means all the water has been removed.
