Organisation of an ecosystem - done Flashcards
What are producers?
Photosynthetic organisms are the producers of biomass for life on Earth
How do producers make their own food?
Using energy from the Sun
Producers’ characteristics: (3)
- start of every food chain (the first trophic level, which is always the biggest)
- can photosynthesise and make glucose by photosynthesis
- They use this glucose to produce other biological molecules, which then make up the producer’s biomass
What does a food chain show?
the transfer of energy from one organism to the next
What is the source of all energy?
light energy from the Sun
Main processes of the CO2 cycle?
- combustion = carbon is released into the atmosphere when fossil fuels are burned
- photosynthesis = plants absorb the CO2 to produce glucose
- plants are eaten by animals. They respire and release CO2
- Decomposition = carbon in dead and decaying matter is broken down
- Fossilisation = of dead plants and animals take in CO2 from atmosphere
What is evaporation?
Energy from the sun turns water from a liquid to a gas
What is transpiration?
Plants allow some water to evaporate from their leaves. This ensures water is continuously pulled up from the soil and travels through the plant to its leaves
What is condensation?
When water vapor cools, water turns from a gas into a liquid.
What is precipitation?
The falling of rain, snow and sleet from the sky
What are the main groups of decomposers?
Bacteria and fungi
What do decomposers do?
When living organisms produce waste products or organisms die, the waste products and dead organisms are broken down
What affects rate of decay?
Temperature, water and availability of oxygen
How does temperature affect the rate of decay?
At warmer temperature, enzymes involved in decomposition can work at faster rate, increasing the rate of decay. If the temperature is too high these enzymes will denature and the rate of decay will decrease
- At low temperatures, the enzymes involved in decomposition work slowly, decreasing the rate of decay
How does water affect the rate of decay?
Decomposers require water to survive. Many decomposers also function by secreting enzymes onto decaying biological matter and absorbing the products of this chemical digestion - without water these reactions cannot occur
WATER AVAILABILITY DECREASES, RATE OF DECAY DECREASES
How does availability of oxygen affect the rate of decay?
Oxygen is needed by decomposers for aerobic respiration - without oxygen, they cannot survive. For these decomposers, the rate of decay decreases as oxygen decreases.
- Some can respire anaerobically resulting in anaerobic decay
What does anaerobic decay produce?
methane gas (as well as carbon dioxide). Together these products are given the term ‘biogas’
What are biogas generators?
Large containers in which animal or plant waste is allowed to decay anaerobically. Can be used to produce methane gas as fuel.
Decay on fresh milk experiment steps:
- Half fill beakers with hot water from kettle and cold water until desired temperature is reached
- Label 4 test tubes - 3 milk, 1 lipase
- In the lipase tube add 10cm of lipase solution. Use a 5cm3 syringe to add 2.5cm3 of milk to each of the milk test tubes
- In milk test tube add 3 drops of cresol red solution
- Using another 5cm3 syringe add 1.5cm3 of sodium carbonate solution to each milk test tube
- Put thermometer in a milk test tube
- Put test tubes in water bath and wait until contents reach the same temp
- Transfer 2cm3 of lipase solution with a pipette into the test tube
- Start stopwatch and stir until their is a colour change. Record time
- Repeat step with different temperatures
Why does the milk’s pH reduce as it decays?
This is because bacteria present in milk carry out a chemical process to provide them with energy. This process converts lactose sugar in the milk to lactic acid, and producing this acid reduces the pH of the milk.
Examples of changing environmental factors that can affect the distribution of organisms include: (3)
- Temperature
- Availability of water
- Composition of atmospheric gases
Human activities that are reducing biodiversity in ecosystems: (3)
- Producing waste, landfill and toxic chemicals
- Deforestation
- Global warming (lead to flooding and extreme weather events)
Ways humans rely on many other species to survive: (3)
- Photosynthetic organisms to produce oxygen, without which we cannot respire
- Pollinator species such as bees to pollinate our food crops
- Plant species for medicine
Effects of rapid human population growth?
- More resources are used to sustain the growing human population
- More waste is produced
- More pollution is created
