Chapter 23 - Energy & Ecosystems Flashcards
How do autotrophs make their own food
absorb light energy –> convert it to chemical energy using the process of photosynthesis –>= glucose provides the cells with energy to survive
Define: biomass
the amount of energy trapped in the body of organisms (10%) (used to make more of the organism)
10% is biomass. what is the 90% of energy gained used for
life processes eg muscle movement, respiration, wastes or heat
how is biomass measured
dry weight per unit of area
Explain: Efficiency of photosynthesis
measured by percentage of light that falls on them that is converted into glucose
about 1%
the rest is reflected away,moves through the leaf, not absorbed by chlorophyll
energy is also lost during respiration, heat energy
Explain 2 steps of: efficiency of consumers
- how much of the available producer biomass is consumed
- how much of what they consume is converted into living matter
MUCH IS LOST AS HEAT
Explain: Productivity of a community
measured by the amount of biomass produced per year
to compare the efficiency of different communities = productivity is calculated as mass per hectare per year
based on performance of produces –> the rate at which energy from sunlight is used in photosynthesis to produce organic matter
Explain primary productivity
the production of biomass resulting from photosynthesis
highest in areas which receive high levels of light energy eg the tropics
can be increased when limiting factors are increased (eg fertiliser)
What does eutrophic mean and what does it do
high nutrient levels
enables increased growth of producers
EG ALGAL BLOOM –> depletes oxygen –> dead organisms
Explain greenhouse effect
Explain the bad effect of FF
is GOOD
influences temperature of the earth
suns heat energy enters the earths atmosphere more easily than it can leave
trapping of some of the suns energy –> warms the earth –> LIFE
burning of fossil fuels –> release CO2 –> thickening atmosphere –> climate change (traps heat) –> warming of global temp.
