Ecology

Created by

Amelie Viney

Cards (41)

State the levels of organisation in an ecosystem:
Individual, population, community, ecosystem
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 interspecific competition?
Competition between different species
What is interdependance?
Mutual reliance or dependence between two or more species
Abiotic factors affecting an ecosystem:
Light intensity
Temperature
Moisture
Soil pH and mineral content
Wind intensity and direction
Carbon dioxide level
Oxygen level
Why might light intensity affect an ecosystem?
Different species of plants may have different optimum light intensities for growth
How does moisture level affect an ecosystem?
Many plants cannot survive in waterlogged soil as their roots cannot respire
Give three examples of extreme living environments:
High temp
High pressure
High salt concentration
Where can extremophile bacteria be found?
In deep sea vents
Define population:
A species that occupy the same habitat
Define community:
Populations of different species interacting
Define ecosystem: 
The interactions between biotic and abiotic factors in an area
Define biomass:
The total mass of living material
What do arrows in a food chain represent?
The direction of biomass transfer
Describe a simple food chain:
Producer-> primary consumer-> secondary consumer-> tertiary consumer
Describe how materials cycle through the living and non living components of an ecosystem:
> Organisms take in elements from their surroundings
> Elements converted to complex molecules which become biomass
> Elements transferred along food chains
> Elements returned to environment during excretion and decomposition of dead organisms
Describe the carbon cycle: 
> Plant fix carbon dioxide into organic molecules during photosynthesis
> The organic carbon containing molecules are passed into 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 back into the atmosphere
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 useful to life on land
> The water then returns to rivers and oceans through surface runoff
Why are microorganisms 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 mineral ions to the environment for other organisms to use
How do decomposers break down dead matter?
They release enzymes which catalyse the breakdown of dead material into smaller molecules
How does soil water content affect the rate of decomposition?
> 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 sulfur dioxide impact the environment?
Formed when fossil fuels containing impurities are burnt
Sulfur dioxide can dissolve in water to form acid rain which can erode buildings and pollute water sources
How does carbon monoxide impact the environment?
Carbon monoxide is formed from the incomplete combustion of fossil fuels
Carbon monoxide binds irreversibly to haemoglobin which prevents it from carrying oxygen
Name 5 greenhouse gases:
Water vapour
Carbon dioxide
Nitrous oxide
Methane
CFCs
How do greenhouse gases lead to global warming?
Greenhouse gases allow heat from the sun to enter the atmosphere
The gases act as a blanket and trap the heat in the atmosphere
Why is biodiversity important?
To maintain the stability of an ecosystem because it reduces dependance on one particular species for resources
How does eutrophication occur?
> Fertiliser from farms pollute the water, causing excessive algae growth, 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
What does a food chain show?
the feeding relationships between organisms and the resultant stages of biomass transfer
How do decomposers break down dead matter?
> decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules
> soluble small food molecules then diffuse into the microorganisms
What is biomass? 
the dry mass if all the living organisms in an area
Why is dry mass used for biomass?
Because wet mass varies as the volume of water in the organism varies
What percentage of the incident energy from light or for photosynthesis do producers transfer?
1%
What percentage of the biomass from one trophic level is transferred to the level above it in feeding?
10%
What biological factors threaten food security?
rising birth rates
new pathogens
environmental changes affecting food production
Advantages of intensive farming:
higher yield of food
more efficient
allows easier quality control
Disadvantages of intensive farming:
may lead to antibiotic resistance
cost is high
ethical objections
biodiversity may be reduced
What is mycoprotein?  
a protein rich substance used to make meat substitute food for vegetarians and vegans