B4 Flashcards
What is an ecosystem?
An ecosystem is all of the living organisms and physical conditions in an area
What is a community?
A community is the organisms within the ecosystem
What is a habitat?
A habitat is an area in which organisms live
What is a population?
A population is the total number of organisms of each species
What are producers?
Producers are organisms that make their own food by photosynthesis
What are consumers?
Consumers are organisms that can’t make their own food. They have to eat other organisms to gain energy
What are decomposers?
Decomposers are a special group of consumers, that gain their energy by feeding on dead or decaying material
What to arrows in a food chain show?
The arrows show the transfer of biomass, and therefore energy transfer
What are the steps in a food chain known as?
Trophic levels, and these include producers primary consumers secondary consumers tertiary consumers
What are biotic factors?
Biotic factors are the living factors of an ecosystem
What are abiotic factors?
Abiotic factors are the non-living or physical factors of an ecosystem
How can biotic factors affect ecosystems?
Biotic factors can be affected by predators and the amount of food in an ecosystem
What 4 abiotic factors affect ecosystems?
Temperature, light intensity, moisture levels and soil pH affect ecosystems
Light intensity
Light is required for photosynthesis, so the greater the light intensity, the greater the success of the plant
Temperature
Plants develop more rapidly in warmer temperatures as their metabolisms will be faster
Moisture level
For most plant and animal species a lack of water leads to death, due to osmosis. Plants also need water for photosynthesis
Soil pH
The pH of soil affects the biological activity in soil and the availability of certain minerals
What is the importance of interdependence in a community?
In order to survive, organisms need to depend on each other
Interdependence - Predation
This the relationship between a predator and prey species. the size of the predator population greatly affects the size of the prey population
Interdependence - Mutualism
In a mutualistic relationship both organisms benefit from the relationship
Interdependence - Parasitism
In a parasitic relationship only one organisms gains from the relationship while the other suffers
What do pyramids of numbers show?
Pyramids of numbers show the population at each trophic level
Describe pyramids of biomass
Pyramids of biomass take into account both the number and size of organisms present
How do you calculate biomass?
Measure the average mass of organism and multiply it by the number of organisms present
How do you draw a pyramid of biomass?
You decide on a sensible scale and plot the biomass accordingly for each trophic level
How is biomass lost between trophic levels?
Biomass is lost when: Not all of an organism is eaten Respiration Egestion Excretion
How much biomass is converted into new body tissue by food?
only around 10%
Why is biomass lost in respiration? (2)
Respiration produces ATP, and muscles use this ATP to produce movement. Respiration also causes energy to transfer to the environment.
How is energy transferred to producers?
by sunlight
How much energy do producers transfer into chemical stores?
only around 1%
How is energy that isn’t transferred to chemical stores used by producers? (3)
Lots of light is reflected from the leaf
Up to half the energy transferred by photosynthesis is transferred by respiration
The remaining energy is transferred to increase the plants biomass
Why is biomass lost through egestion?
Egestion is where undigested parts of an organism are removed from the body in faeces
Why is biomass lost through excretion?
Excretion is when waste products are lost by the body
How do we calculate the efficiency of biomass transfer?
efficiency of biomass transfer (%) = biomass available after transfer (amount gained/lost - kg or g) / biomass available before transfer (kg or g) x 100
How does the efficiency of biomass transfer affect the number of trophic levels in a food chain?
It is affected because the number of trophic levels are determined by the amount of energy that can be transferred to sustain life processes.
Many different materials …
cycle through the biotic and abiotic components of an ecosystem
Give 3 examples of materials that are cycled through the ecosystem
nitrogen, carbon and water
Draw a diagram to summarise nutrient cycling + label processes
see p.g. 140, absorption, digestion and feeding, death, decomposition need to be included as processes
Explain the importance of carbon to living organisms
Carbon is used to make carbohydrates, fats proteins and DNA which are essential to organisms
Explain the importance of nitrogen to living organisms
Nitrogen is used by organisms to make DNA and proteins
Explain the importance of water to living organisms
All living organisms need to drink or absorb water to survive
Water also determines the physical characteristics of many habitats necessary for particular organisms to survive
Draw a labelled diagram of the nitrogen cycle
see p.g. 141
Draw a labelled diagram of the water cycle
see p.g. 141
How does nitrogen pass into animals?
When a plant is eaten the nitrogen compounds are passed onto the animal
How does nitrogen pass into decomposers and what do they do to them?
When plants and animals die the nitrogen compounds get broken down and are released back into the soil as ammonia
How does nitrogen pass back into the soil?
Nitrifying bacteria converts the ammonia into nitrites, and then into nitrates
How does nitrogen pass back into the air?
Denitrifying bacteria releases nitrogen into the air
What is a way in which nitrogen is passed into plants through bacteria?
Nitrogen passes into plants using nitrogen fixing bacteria, which combine nitrogen from the air with oxygen to form nitrates
What is a way in which nitrogen is passed into plants through bacteria?
Nitrogen passes into plants using nitrogen fixing bacteria, which combine nitrogen from the air with oxygen to form nitrates
What does the water cycle move through? (ROALS)
Rivers, Oceans, Atmosphere, Lakes, Soil
Evaporation
The Sun heats the Earth’s surface and water is turned from a liquid into water vapour forming warm moist air
Condensation
As moist air rises it cools. Water vapour condenses back into liquid water droplets producing clouds
Precipitation
As water droplets in clouds get heavier they fall as rain, snow or hail
Percolation
Water trickles through gaps in soil and rocks
Transpiration
Loss of water vapour from plants directly to the atmosphere
Transpiration
Loss of water vapour from plants directly to the atmosphere
Draw a labelled diagram of the carbon cycle
see p.g. 142
Photosynthesis and carbon
Carbon dioxide is removed from the environment during photosynthesis. Carbon dioxide and water are converted into glucose and oxygen
Glucose and carbon
Glucose is a simple sugar that can be used to make complex carbohydrates such as starch, fats and proteins. This enables plants to grow and develop, and carbon is part of the extra biomass
Animals and carbon
When animals eat plants, carbon in the plant is transferred to the animal
How is carbon released into the atmosphere?
Respiration
Decomposition
Burning fossil fuels
Respiration and carbon
All living organisms respire, and as a result carbon dioxide is released
Decomposition and carbon
When plants, algae and animals die decomposers break down their remains, releasing carbon dioxide as they respire
Burning fossil fuels and carbon
When fossil fuels burn the trapped carbon in them is released
What are decomposers?
Decomposers are microorganisms, which break down or decay dead organic material. They also break down animal waste
What is decomposition?
Decomposition is the process in which decomposers break down material and nutrients are released which can then be recycled
What are detritivores?
Detritivores are small animals that speed up decomposition by shredding organic material into very small pieces
What are micro-organisms role in releasing nutrients?
Microorganisms release enzymes that break down substances in the organic matter. They then absorb the soluble nutrients into their bodies and use them for growth as an energy store
What are micro-organisms role in releasing nutrients?
Microorganisms release enzymes that break down substances in the organic matter. They then absorb the soluble nutrients into their bodies and use them for growth as an energy store
What factors affect the rate of decomposition?
Temperature, Moist environments and aerobic/anaerobic conditions
affect the rate of decomposition
Warm temperatures for decomposition
At warm temperatures, enzymes for decomposition work best.
High - enzymes denature
Low - enzyme reaction are slow
Moist environments for decomposition
If not enough water is available reactions will slow down or be prevented, which will stop the process of decomposition
Aerobic/Anaerobic conditions for decomposition
Aerobic conditions - decomposition takes place as microorganisms can respire
Anaerobic conditions - decomposition is prevented as micro-organisms cannot survive
How do you calculate the rate of decay of biological material?
rate of decay (g/day) = change in mass (g) / time (days)
