topic 7:ecology Flashcards
State the levels of organisation in an ecosystem
Individual, population, community, ecosystem
What is an ecosystem?
The interaction between the living components and nonliving components
State the factors that plants may compete for
light
Space
Water
Mineral ions from soil
State the factors that animals might compete for
Food
Mates
Territory
what is intraspecific competition?
Competition within a species
What is interdependence?
different species in an ecosystem depend on each other for various resources, if one species is removed, the whole community may be affected 
What is a stable community?
A community in which all the biotic factors and all abiotic factors are balanced so that population sizes remain relatively constant
What are abiotic factors?
Nonliving factors
State the abiotic factors that may affect ecosystem
light intensity
Temperature
Moisture
Soil pH and mineral content
Wind intensity and direction
Carbon dioxide level
Oxygen level
why might light intensity affect ecosystem?
Different species of plants may have different optimum light intensity for growth
why does temperature affect an ecosystem?
Different species of plants and animals may have different optimum temperatures for growth and survival
How does soil pH affect an ecosystem?
certain plants may grow better in either alkaline or acidic soil
Soil pH may affect the appearance of the plant e.g. colour of hydrangea
How does moisture level affect an ecosystem?
many plants cannot survive in waterlogged soil as their roots cannot respire
Certain plants are adapted to high moisture levels
How does wind intensity affect an ecosystem?
Plant seeds are more likely to germinate in locations with lower wind intensity, which may also attract animals that depend on plant to live nearby
how does soil mineral content affect an ecosystem?
Most plants require a high level of soil minerals to grow well
Give an example of a type of plants that have adapted to low soil mineral content
Carnivores plants catch insects to compensate for the low level of soil mineral content
How does carbon dioxide concentration affect an ecosystem?
Higher carbon dioxide concentration leads to more plant growth
How does oxygen concentration affect an ecosystem?
Aquatic animals cannot survive in areas with low oxygen concentration
State the biotic factors that may affect an ecosystem
food
New predators
New pathogens
Competition
What are adaptations?
Features that enable organisms to survive in their living environment
what are organisms living in extreme environments called?
extremophiles
give free examples of extreme living environment
High temperature
High pressure
High salt concentration
State an example of where extremophile bacteria can be found
in deep sea vents
Define population
A species that occupy the same habitat
Define habitat
The place in which an organism lives
define community
Populations of different species interacting
Define ecosystem
The interactions between their biotic and abiotic factors in an area
what do food chain show?
Food chain show the feeding relationships of different organisms and the flow of energy between the organisms
Define biomass
The total mass of living material
what are trophic levels
The stages in a food chain
What do arrows in a food chain represent?
The direction of biomass transfer 
Describe a simple food chain
produce—-> primary consumer——> secondary consumer—-> tertiary consumer
What is a producer?
An organism that makes its own food
what type of organisms are primary producers
Photosynthetic organisms like green plants and algae that trap energy from the Sun
what is a primary consumer?
An organism that feeds on producers
What is a secondary consumer?
An organism that feeds on primary consumers
what is a tertiary consumer?
An organism that feeds on secondary consumers
What is a predator?
A consumer that kills and eat other animals
What is pray?
An animal that is killed and eaten by another animal
Describe the pattern of predators and pray in a stable community
The numbers of predators and pray rise and fall cycles
Why are producers the first trophic level?
produces provide all biomass for the food chain
The rest of the food chain involves the transfer of this bio mass
what piece of apparatus is used to measure the abundance and distribution of organisms in an area?
Quadrat
what piece of operators is used to study the distribution of organisms across a gradient?
belt transect 
When considering the abundance of organisms, what is meant by the term mean?
The average number of organisms
how is the arithmetic mean calculated?
some of each number of each organism
Divide
The total number of each type of organism
When considering their abundance of different organisms, what is meant by the term mode?
The most populous organism
when considering the abundance of organisms, what is meant by the term median?
The organism that represents the middle value when the numbers of each organism are arranged from lowest to highest
describe how material cycle through the living and nonliving components of an ecosystem
Organisms take in elements from their surroundings, e.g. soils, air
Elements converted to complex molecules which become biomass
Elements transferred along food chain
Elements returned to the environment during excretion and decomposition of dead organisms
Give three molecules which are cycled for ecosystem
Oxygen, carbon dioxide and water
Describe the carbon cycle
plants fix carbon dioxide into organic molecules during photosynthesis
The organic carbon containing molecules are passed onto organisms that eat the plants
Carbon Dioxide is released back into the atmosphere by respiration from animals and plants
Burning fossil fuels also releases carbon dioxide into the atmosphere
why is the carbon cycle important?
Carbon contain molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells
Describe the water cycle
water from Lakes and oceans evaporates
The evaporated water condenses into clouds and returns to earth as precipitation
The water from precipitation is used for life on land
The water then returns to rivers and oceans through surface run-off
why is the water cycling important?
Living organisms require water and the water cycle provides organisms on land with a continuous supply of water
Why are micro organisms important for the cycling of materials through an ecosystem?
microorganisms return carbon to the environment by releasing carbon dioxide through respiration while they decompose dead matter. The decomposition of dead matter in soil returns minerals to the environment for other organisms to use e.g. plants use mineral irons for growth.
What is meant by decomposition?
The breakdown of dead materials into simpler organic matter
How to decompose breakdown dead matter
Decomposers where these enzymes which catalyse the breakdown of dead material into smaller molecules
what are the two types of decomposition?
Aerobic decomposition with oxygen
Anaerobic decomposition without oxygen
What factors affect the rate of decomposition?
oxygen availability
Temperature
Water content
why is oxygen required for decomposition?
Most decomposers require oxygen for aerobic respiration
How does the availability of oxygen affect the rate of decomposition?
as oxygen levels increase, the rate of decomposition increases
As oxygen levels decrease the rate of decomposition decreases
Why can decomposition still occur in the absence of oxygen?
some decomposers respire anaerobically
However, the rate of decomposition is slower as anaerobic respiration produces less energy
How does soil water content affect the rate of decomposition?
decomposers require water to survive
in moist conditions the rate of decomposition is high
In waterlogged soils, there is little oxygen for respiration so the rate of decomposition decreases
why does decomposition require water?
Water is required for the secretion of enzymes and absorption of dissolved molecules
How does temperature affect the rate of decomposition?
decomposers release enzymes
Rate highest at 50 Celsius
Lower temperature, enzymes work too slow slowly, rate decreases
Higher temperatures, enzymes denature, decomposition stops
how is the rate of change calculated when considering the decay of biological material?
Rate of change= change in value
————————
Change in time
where value is a measurable variable associated with the decay of the material
what is compost
The nutrient rich product of the rapid decay of waste biological material(dead plants and animal waste) iin optimum condition set by gardeners and farmers
How is compost used?
Use is a natural fertiliser to promote growth of crops or garden plants
Describe how biogas generators work
Bio gas generators provide methane gas for fuel through anaerobic decomposition that occur in animal waste
Describe how environmental conditions affect communities
environmental conditions, e.g. temperature, soil pH, light intensity affect the abundance and distribution of organisms within communities
E.g. rising global temperatures that have been linked to extension of frog species(their thin skin makes them more vulnerable to temperature changes)
how can different temperatures be bad for certain communities?
If the temperature is too low, growth will be slower as organisms will use more energy to stay warm
If the temperature is too high organisms can die and water will become limited as evaporation increases
How can changes in water levels affect ecosystems?
animals may have to migrate to find water
Melting ice caps may destroy the habitats of some animals
How can atmospheric gases affect ecosystems?
some organisms cannot survive when certain gases are present
Polluted water can cause illness to animals that drink it
What detrimental impacts can sulphur dioxide have on the environment?
formed when fossil fuels containing impurities are burnt
Sulphur dioxide can dissolve in water to form acid rain which can road buildings and pollute water sources
What detrimental impacts can carbon monoxide have on environment?
carbon monoxide is formed from the incomplete combustion of fossil fuels
Carbon monoxide binds irreversible to haemoglobin which prevent it from carrying oxygen
Too much pressure can cause unconsciousness and death
Name five greenhouse gases
water vapour
Carbon dioxide
Nitrous oxide
Methane
CFCs
A 3 human activities that contribute to greenhouse gases
Burning fossil fuels
Deforestation
Large scale livestock farming
how do greenhouse gases lead to global warming?
Greenhouse gases allow heat from the Sun to enter the atmosphere
The gas gases act as a blanket and trap the heat in the atmosphere
State three negative consequences of global warming
Sea level rise caused by melting icebergs
Distributed farming and agriculture
Increase spread of diseases in warmer climates
What is biodiversity?
Variety of the different species on earth or within an ecosystem
What is the importance of biodiversity?
To maintain the stability of an ecosystem
how does biodiversity ensure the stability of an ecosystem?
It reduces the dependent on particular species for resources, e.g. food and shelter to that even if one species is removed over species can still survive
why have humans consumption of resources and waste production increased?
Rapid rising human population
Increase in standard of living
Where does pollution occur?
Air, land, water
State an example of water pollutants
Sewage, fertiliser, chemicals
how does eutrophication occur?
Fertiliser from farms pollute the water, causing excessive algae, depleting the oxygen in the water, causing other plants and animals to die
Dead plants are decomposed by bacteria and the oxygen levels decrease further
State an example of air pollutants
Smoke
Acidic gases
State an example of land pollutant
Landfill waste, chemicals
Which human activities reduce the land available for animals and plants?
building, farming, quarrying, disposing of waste
why have Peat bogs been destroyed?
To produce compost to increase food production
why does the destruction of peatBoggs greatly contribute to the greenhouse effect?
peat bogs are stores of carbon and burning their releases a large volume of carbon dioxide into the atmosphere
why have large scale deforestation activities occurred?
To provide land for cattle or Ricefield
To grow crops to produce biofuels
what is the greenhouse effect?
Greenhouse gases trapped energy from the Sun as heat in the atmosphere keeping the temperature on Earth suitable for life
What is causing global warming?
The increase in levels of greenhouse gases, e.g. carbon dioxide in methane, causing the temperature on Earth to increase
What are the harmful effects of deforestation?
destruction of many animal habitats
Releases large amounts of greenhouse gases
State the consequences of global warming
Rising sea levels
Melting polar ice caps
Changing weather patterns
Migration of animals to find suitable habitats
Tropical diseases becoming more common
Extinction of species
Describe the steps taken to maintain biodiversity
breeding programs for endangered species
Protection and rebuilding habitats
replanting field margins and hedgerows
Reduce deforestation
Reduce carbon dioxide emissions
Recycling rather than disposing in landfills
What is the purpose of replanting hedgerows and field margins?
There is a higher by diversity in the margins than the fields that they surround
what does a food chain show?
It describes a feeding relationship between organisms and the resultant stages of biomass transfer
what are trophic levels
The stages in a food chain
how are trophic levels represented?
Trophic levels are represented by number numbers, starting from one. After one, trophic levels are numbered according to far along the organism is in the food chain.
what is trophic level one?
Plants and algae which make their own food through photosynthesis – called producers
what is trophic level two?
Herbivores which eat producers – called primary consumers
what is trophic level three?
Carnivores that eat herbivores – called secondary consumers
What is trophic level four?
Carnivores that eat other carnivores – called tertiary consumers
what is an Apex predator?
A carnivore with no predators
How do composers breakdown dead matter?
Decomposers releases enzymes which catalyse the breakdown of dead material in smaller icicles. So both small food molecules then diffuse into microorganisms.
what is biomass
The dry mass of all living organisms in an area
Why is dry mass used for biomass 
Because the wet mass varies as the volume of water in the organism varies
what percentage of the incident energy from light for photosynthesis do producers transfer
1 percent
What percentage of the biomass from one trophic level is transferred to the level above it in feeding
Approximately 10%
Why are buyer mass transfer is not 100% efficient?
Energy is lost through
egestion
Excretion
Respiration in which large amounts of glucose are used
The production of inedible bones and shell
how does the efficiency of biomass transfers affect the number of trophic levels in a biomass pyramid?
The less efficient the transfers, the fewer trophic levels are the few organisms in higher trophic levels
What is a biomass pyramid?
A pyramid that shows the total dry mass of organisms at each trophic level
Trophic level one is at the bottom of the pyramid
What is a pyramid of numbers?
A pyramid of number shows the number of organisms at each trophic level
Identify the producer in this pyramid of biomass
D is the producer
why is this pyramid of numbers not pyramid shaped?
Pyramids of numbers don’t take size and mass of organisms into account
what is food security?
having enough food to be able to feed a population
State the biological factors of threatening food security
rising birth rates
Changing diets in developed countries – food is transported around the world
New pests and pathogens
environmental changes affecting food production
Increase cost of agriculture
Armed conflicts
How does intensive farming increase the production of animals?
Feed animals high protein foods to increase growth
Reduce the energy loss to the environment:
-Limiting movement
-Regulating their surrounding temperature
Feed animals, antibiotics to prevent diseases
What are the advantages of intense farming?
 high yield of food
More efficient
Allows easier quality control
what are the disadvantages of intense farming?
May lead to antibiotic resistance
Cost is high
Ethical objections, e.g. limiting movement of animals may cause them harm
Biodiversity may be reduced
how can fish stocks be conserved?
Control the size of gaps in fishing nets to prevent juvenile fish from being killed. Before reaching reproductive maturity.
Introduced fishing quotas
what is a transgenic organism
an organism that has been genetically modified to contain genetic material from another source
Stay an example of genetically modified foods
Golden rice
how might crops be genetically modified?
to improve nutritional value
To be pest resistance
To be pesticide resistant
what are the advantages of golden rice
 it contains additional beta- carotene which can be converted to vitamin A in the body, supplementing people who do not obtain enough vitamin A in their diet to prevent Nightblindness from farming 
what is mycoprotein?
A protein rich substance used to make meat substitute food for vegetarians and vegans
how is mycoprotein produced
fusarium-a fungus, is grown on glucose syrup, in aerobic conditions and the biomass is harvested and purified to get the mycoprotein
