Topic 7 - Ecology Flashcards
What is an ecosystem ?
The interaction of a community of living organisms with the non-living parts of their environment.
What is a community ?
All of the living organisms within a habitat
List 3 things which animals compete for
1) Food
2) Mates
3) Territory
List 4 things which plants compete for
1) Light
2) Space
3) Minerals (ions)
4) Water
What is interdependence ?
Where species depend on other species
What is a stable community ?
Where all the species and environmental factors are in balance so that population sizes remain fairly constant.
What are abiotic factors ?
Non-living factors
What are biotic factors ?
Living factors
What are 6 abiotic factors ?
-Moisture level
-Temperature
-Levels of oxygen or carbon dioxide
-pH levels
-Light intensity
-Weather (wind)
What are 4 biotic factors ?
-Food availability
-New predators
-Competition
-Pathogens
What are adaptations ?
Any feature that allows an organism to survive in it’s habitat
Name the three types of adaptation
-Structural
-Functional
-Behavioural
Name a type of structural adaptation
Thorns on a rose
Name a type of functional adaptation
Snakes having venomous bites
Name a type of behavioural adaptation
Hibernating during winter
What are extremeophiles ?
Organisms that are adapated to live in extreme conditions
What is biomass ?
The total mass of biological material in a given area or population
Where does all biomass come from ?
Producers
Lettuce-> slug–>blackbird–> sparrow hawk
Identify the trophic levels in this food chain.
Lettuce - Producer
Slug - Primary consumer
Blackbird - Secondary consumer
Sparrow hawk - Tertiary consumer
Why does the population of predators and prey fluctuate ?
-When the populations of prey decreases there is less food available for the predators,
-so fewer were able to survive
-so the population decreases
-Fewer predators means less predation so more prey were able to survive
-so the population increases
-More prey means more food for predators so their population increases
-More predators means more predation so fewer prey survive
Describe the trophic levels
Level 1: producers.
Level 2: primary consumers.
Level 3: secondary consumers.
Level 4: tertiary consumers.
Describe the role of decomposers
Break down plant and animal matter through enzymes released
How do you calculate the efficiency of energy transfer ?
efficiency = (biomass of trophic level/biomass of trophic level below) x 100
Name 3 reasons why not all biomass is transferred
-Some lost as faeces and urine
-Some lost through respiration as carbon dioxide
-Not all biomass is consumed by the next trophic level (bones, feathers etc).
Why is the number of organisms lower at the higher trophic levels ?
There is less biomass / energy being transferred as you move thorught trophic levels, so less organisms can be supported.
What is the purpose of random sampling ?
To estimate abundance (size of a population)
How do you achieve random sampling ?
By using randomly generated numbers to make coordinates in a grid. Place a quadrat at each of the randomly generated coordinates.
Why should sampling be random ?
To avoid bias
Why might you use a transect instead of random sampling ?
To measure distribution over an area or with a specific abiotic factors.
How do you carry out a transect ?
Lay out a tape measure across the area to be studied. Place a quadrat at regular intervals along the line and record the species present.
How do you find the mean amount of individuals per quadrat ?
Sum of the individuals in all quadrats / Number of quadrats
What is the state change when a liquid turns to a gas ?
Evaporation
What process removes water from the atmosphere ?
Photosynthesis
What process releases water into the atmosphere ?
Respiration
Where is water stored in organisms ?
In their bodies
Describe the water cycle
1) Water can be stored within the bodies of organisms
2) Some water can be transferred to the atmosphere through respiration and evaporation
3) Some water can be removed from the atmosphere through photosynthesis
4) Water can drain from the land into the rivers and seas
Describe the carbon cycle
1) Carbon can be stored within the bodies of plants and animals.
2) Some carbon is transfered to the atmosphere by respiration as carbon dioxide
3) Carbon dioxide can be removed from the atmosphere by photosynthesis
4) Some carbon is transferred to the atmosphere by the death and decay of organisms
5) Some carbon is trapped in the bodies of organisms that become fossil fuels
How do decomposers help cycle nutrients through an ecosystem ?
They can break down dead material to release the nutrients (ions) to the soil which can then be uptaken by other organisms
Describe how the temperature, water and oxygen levels impact the rate of decay
Temperature: increased temperature causes rate of decomposition to increase. Decomposition stops if temperature becomes too high
Water: decomposition only occurs with water available
Oxygen: increased oxygen causes rate of decomposition to increase
Describe why too high temperatures stop decomposition
Decomposition stops at high temperatures as enzymes are denatured
Describe why increased oxygen increases the rate of decomposition
increased oxygen increases rate of respiration and therefore rate of decomposition
Describe the purpose of compost
Compost is used as a natural fertiliser for growing crops
What does anaerobic decay produce ?
Methane
What is the purpose of biogas ?
To decompose waste material and produce methane gas as a fue
What is biodiversity ?
The variety of different species of organisms on the earth or in an ecosystem
Why is higher biodiversity beneficial ?
Great biodiversity means the ecosystem is less dependent on one species, so if the population falls it will be less likely to affect the ecosystem.
Why is biodiversity important for humans ?
Humans rely on other organisms for food, medicines and building materials.
What 3 activities reduce biodiversity ?
1) Deforestation
2) Global warming/ Pollution
3) Over hunting/ fishing
What has caused an increase pressure on land and resources ?
An increase in the global population
Describe water pollution
Sewage or toxic chemicals in rivers or water sources
Describe air pollution
Smoke, toxic or acidic gasses being released into the atmosphere
Describe land pollution
Dumping of rubbish in landfill
What are the consequences of increased pollution ?
Animals and plants are killed which reduces biodiversity
How do humans reduce the land available for other organisms ?
Building, Farming, Waste disposal and quarrying
Describe the link between farming and the 3 types of pollution
Water pollution- fertilisers get into water bodies.
Air pollution-machinery produces acidic gases.
Land pollution- soil erosion, pesticides
What is peat ?
Partially decomposed organic matter
Why is peat important in the carbon cycle ?
Peat stores a lot of carbon
What happens when peat is burned ?
Carbon is released into the atmosphere which links to clilmate change/ global warming
Name 3 human activities which add to the amount of greenhouse gases
1) Burning of fossil fuels
2) Deforestation
3) Agriculture
What is global warming ?
The change in global temperatures and climates
Describe 2 biological impacts of climate change
1) Reduction in biodiversity
2) Increase in the levels of disease
What is deforestation ?
The large scale removal of naturally grown forests
How does deforestation contribute to global warming ?
1) Burning of trees can release carbon dioxide into the atmosphere
2) Trees can no longer photosynthesise and remove carbon from the atmosphere
What is meant by maintaining biodiversity
Keeping the distribution and populations of species constant
What are 5 actions to maintain biodiversity levels ?
1.Breeding programmes for endangered species
2.Protection and regeneration of rare habitats
3.Reintroduction of field margins and hedgerows
4.Reduction in deforestation and carbon dioxide emissions
5.Recycling resources
What is food security ?
Having enough food to feed a population.
Name 6 factors which threaten food security
- increasing birth rate
- changing diets in HIC
- New pests and pathogens
- environmental changes (droughts)
- cost of agricultural inputs
- conflicts/war
What is sustainability ?
Meeting the needs of people today without impacting the needs of people in the future
Describe 3 issues with the fishing industry
-Fish stocks have declined dramatically.
-Breeding is threatened.
-There is a risk of extinction
Explain how larger holes in fish nets help maintain population sizes
Large holes in nets enables smaller fish to escape, so they can continue to grow to matuirty and therefore breeding age.
Describe some conflicts between increasing food security and animal welfare
-intensive farming is viewed as cruel –Use of pesticides and fertilisers is damaging the environment.
List 2 biochemical solutions to food insecurity
- Genetic modification
- Use of microorganisms
What is mycoprotein ?
A protein rich food suitable for vegetarians.
Describe how the fungus Fusarium is used to produce mycoprotein.
The fungus is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified.
Explain how genetic modification can help increase food security
GM crops could provide more food or food with an improved nutritional value
What is golden rice ?
A variety of rice that was genetically modified to contain more vitamin A.
