B4.1: Ecosystems Flashcards
What is an ecosystem?
a community of living organisms and physical conditions in a particular area
What is a community?
Organisms within the ecosystem
What is a habitat?
The area where organisms live
What is a population?
The total number of organisms of each species
Which 3 groups are organisms divided into in a community?
Producers
Consumers
Decomposers
What are producers?
Organisms that make their own food by photosynthesis
Plants
Algae
What are consumers?
Organisms that cannot make their own food.
Have to eat other organisms to gain energy
All animals are consumers
What are decomposers?
Special group of composers
Gain energy by feeding on dead or decaying matter
What is biomass?
Mass of living material present
What happens to biomass as an organism grows?
Increases in biomass
What does a food chain display?
What an organism eats
What do arrows in a food chain display?
Transfer of biomass from one organism to another
What is a trophic level?
Each step in a food chain
What does a food chain always begin with?
Producer - grass/plants
What is a prey organism?
Eaten by another organism
What is a predator organism?
It eats another organism
What type of organism may you find at trophic level 1?
Producer
What type of organism may you find at trophic level 2?
Primary consumer
What type of organism may you find at trophic level 3?
Secondary consumer
What type of organism may you find at trophic level 4?
Tertiary consumer
What are biotic factors?
Living factors
What are abiotic factors?
Non-living factors
Rainfall, temp of ecosystem
How do light intensity affect communities?
Greater the light intensity, the greater te success of plants because light is needed to maximise photosynthesis
How do temperatures affect communities?
Effect on enzymes that control metabolic reactions
Plants develop faster in warmer temperatures
Plants and animals have evolved to grow healthily at optimum temps
How do moisture levels affect communities?
Overwatering plants, waterlogged soils, little oxygen
Other plants like pitcher plants, (that grow in bogs) would need high moisture levels
How does soil pH affect communities?
Affects biological activity in soil
Some plants develop better in acidic soils (pH below 7)
Some plants develop better in alkalinic soils (pH above 7)
What is competition within an ecosystem?
Each of the organisms trying to survive in the ecosystem
What MUST animals get access to in order for them to survive?
Food
Water
Space
What MAY animals get access to in order for them to survive?
Sunlight, photosynthesis
Mineral salts
Water
Space
What is interdependance?
When scientists study how different organisms depend on each other within a community
What are ecological relationships?
Interactions between organisms
What are the 3 main types of ecological relationships?
Predation
Mutualism
Parasitism
What is predation?
Name given to the relationship between predators and prey
Size of predator population directly affects the prey population
What is mutualism?
Both organisms benefit from the relationship
What is parasitism?
Only one organism gains whereas the host suffers
What do food chains show?
The flow of biomass through a community
BUT
They dont show the number of organisms involved or size of biomass transferred
What are the food chain diagrams like?
Pyramid shape going from one trophic level to the next
How can you calculate biomass?
Measure average mass of each of the organisms and multiply it by the number of organisms present
What is the efficiency of biomass transfer like?
Usually only 10% is transferred between trophic levels
Remaining 90% is used by organisms in life processes
When can biomass be lost?
Not all of the organism is eaten: bones/roots not consumed
Some biomass used in respiration
Some parts of an organism might not be digestible
Waste products lost through excretion, urine
What is the efficiency of biomass transfer?
(Biomass available after transfer/ biomass available before transfer) x 100%
How can animals put nitrogen back into the soil?
Urine
Faeces
What is the flow of nitrogen like in the nitrogen cycle?
When a plant is eaten, nitrogen compounds are passed onto an animal.
When a plant is eaten and then the plants and animals die, compounds are released and broken down, and released back into soil as ammonia.
How can water determine habitats?
Polar bears rely on ocean ice
Frogs require water to reproduce
Sharks can only survive when being submerged in water
How does the water cycle move water?
Moves water and nutrients through the atmosphere, soil, rivers, lakes and oceans. By doing so, it brings fresh water to people, animals and plants
By which processes does carbon cycle through the atmosphere?
Photosynthesis
Respiration
Combustion
In carbon cycling, how does the carbon start and end in photosynthesis?
Starts as Carbon dioxide
Ends as Glucose
In carbon cycling, how does the carbon start and end in respiration?
Starts as glucose
Ends as carbon dioxide
In carbon cycling, how does the carbon start and end in combustion?
Starts as fuel - methane
Ends as carbon dioxide
How does carbon enter the atmosphere?
Enters as carbon dioxide from respiration and combustion
Who absorb carbon dioxide?
Absorbed by producers to make glucose in photosynthesis
What do decomposers break down?
Dead mattter
Faeces
Urine
What are organisms that feed on dead matter called?
Saprophytes
What are detritivores?
Smal animals
Speed up decomposition by shredding organic material into very small pieces
Creates a larger surface area for decomposers to work on
What are examples of detritivores and what do they break down?
Earthworm: leaves
Woodlouse: wood
Maggot: animal material
What is the formula for the rate of decay?
Change in mass (g) / time (days)
How does temp affect the rate of decomposition?
Temp: high temps prevent decomposition (denature enzymes) but low temps slow it down (slow rate of enzymes)
How does oxygen availability affect the rate of decomposition?
Lack of oxygen will prevent decay
Oxygen is needed for microorganisms aerobic respiration
Without oxygen they will die
Very few organisms can still decompose using anaerobic respiration
How does water availability affect the rate of decomposition?
Lack of water will prevent decay
Water is needed to support reactions inside microorganisms
Decomposers need water to digest
