How do photosynthetic organisms make glucose, and what else is released?
They use light energy to make glucose from carbon dioxide and water, releasing oxygen.
AQA GCSE Combined Science: Trilogy (8464) — Biology — Higher · 4.7.2.1
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How do photosynthetic organisms make glucose, and what else is released?
They use light energy to make glucose from carbon dioxide and water, releasing oxygen.
What is an organism's biomass?
The mass of its living material.
How does glucose contribute to a photosynthetic organism's biomass?
It provides material for making other organic molecules that contribute to biomass.
Why are green plants and algae called producers?
They make organic material rather than obtaining it by eating other organisms.
How does the biomass of producers support other organisms?
It supplies organic material to consumers through feeding relationships.
What is a quadrat used for in species sampling?
It marks out a known area in which organisms can be recorded to estimate species abundance.
Why are repeated quadrats placed at randomly selected positions?
To reduce selection bias and obtain a sample of the study area.
What are two ways to record abundance within a quadrat?
Count or percentage cover, depending on the organisms.
How can mean count per quadrat be used to estimate a population in a study area?
How does more representative quadrat sampling affect the reliability of an abundance estimate?
It improves the estimate’s reliability.
What should be considered about the distribution of organisms when sampling with quadrats?
Organisms are not necessarily distributed evenly.
Which three measures can summarise the typical value of repeated observations, such as organism abundance?
Mean, median and mode.
How is the arithmetic mean calculated?
Add all the values and divide by the number of values.
How is the median of a set of observations found?
Order the values and take the middle one. If there are two middle values, take their mean.
What is the mode of a data set?
The most frequently occurring value.
Can a data set have more than one mode or no mode?
Yes. It may have multiple modes or no mode.