B7 - Ecology Flashcards
What does population mean?
All the members of one species living in a habitat.
What is a community?
The populations of different species living in a habitat.
What is a habitat?
The place where an organism lives.
What is an abiotic factor?
Non-living factors of the environment e.g. temperature.
What is a biotic factor?
Living factors of the environment e.g. food.
What is an ecosystem?
The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
What 6 things do living things fight over?
Food
Sunlight
Water
Mate
Space
Shelter
What are stable communities?
When the species and environmental factors are in balance so population sizes remain roughly constant.
What are 4 biotic factors?
- Food availability
- Disease causing microorganisms
- Predators
- Competition between organisms
What are 10 abiotic factors?
Water
Space
Moisture levels
Nutrients in the soil
CO2 levels
Soil pH
Oxygen level
Wind intensity
Temperature
Light intensity
What are the 4 trophic levels in the food chains?
Producer - plantain
Primary consumer - grasshopper
Secondary consumer - frog
Tertiary consumer - fox
What is a herbivore?
An animal that eats plants.
What is a carnivore?
An animal that eats meat.
What are trophic levels?
The stages in a food chain.
What is trophic level 1?
Producers - they make their own food through photosynthesis.
What is trophic level 2?
Primary consumer - herbivores which eat producers.
What is trophic level 3?
Secondary consumer - carnivores that eat herbivores.
What is trophic level 4?
Tertiary consumers - carnivores that eat carnivores.
What is an apex predator?
A carnivore with no predators.
How do decomposers break down dead matter?
They release enzymes which catalyse the breakdown of dead material into smaller molecules.
The small molecules then diffuse into the microorganisms.
What is biomass?
The dry mass of a living organism.
Why is dry mass used for biomass?
Because the wet mass varies, because the volume of water in an organism varies.
How do you calculate the efficiency of biomass transfer?
efficiency = (energy transferred / total energy available) x 100
What percentage of the incident energy from light do producers transfer?
1%
What percentage of the biomass from one trophic level is transferred to the level above it in feeding?
Approximately 10%
Why are biomass transfers not 100% efficient?
Energy is lost through:
- excretion and egestion
- respiration
- the production of inedible shells and bones
How does the efficiency of the transfers affect the number of trophic levels in a biomass pyramid?
The less efficient the transfers the fewer trophic levels and the fewer organisms in the higher trophic levels.
What is a biomass pyramid?
A pyramid that shows the total dry mass of organisms at each trophic level.
What is a pyramid of numbers?
It shows the number of organisms at each trophic level.
Why are pyramids of numbers not as widely used as pyramids of biomass?
They don’t take the size and mass of organisms into account.
Why are pyramids of biomass useful?
Because they depict how much food is available for the next level of the food chain.
What controls the amount of carbon in the atmosphere?
The carbon cycle.
What 2 processes take carbon dioxide from the atmosphere?
- Photosynthesis by plants
- Dissolving in the ocean
What 2 processes release carbon dioxide to the atmosphere?
- Respiration by plants, animals and microbes.
- Combustion
What human activities has led to a higher proportion of carbon dioxide in the earths atmosphere?
Burning fossil fuels as energy sources.
Deforestation, meaning there is less photosynthesis that removes carbon dioxide from the air.
What happens when organisms die or produce waste?
Dead matter and waste is decomposed by decomposers (bacteria and fungi) and detrivores.
What are detritivores?
Consumers such as woodlice and worms.
State the levels of organisation in an ecosystem.
Individual, population, community, ecosystem.
What is intraspecific competition?
Competition within a species.
What is interspecific competition?
Competition between different species.
What is interdependence?
Different species in an ecosystem depend on each other. If one species is removed, the whole community breaks down.
What is a stable community?
A community in which all the biotic factors and abiotic factors are stable so the population sizes remain relatively constant.
Why might light intensity affect an ecosystem?
Different species of plants have different optimum light intensities for growth.
Why does temperature affect an ecosystem?
Different species of plant and animals may have different optimum temperatures for growth and survival.
What plant has it’s appearance altered by soil pH?
Hydrangea.
How does soil pH affect an ecosystem?
Certain plants may grow better in either an alkaline or acidic soil.
How does moisture levels 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 moisture levels affect an ecosystem?
Plants seeds are more likely to germinate in locations with a lower wind intensity, which may attract animals that depend on the 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 the type of plants that have adapted to low soil mineral content.
Carnivorous plants catch insects to make up 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 a low oxygen concentration.
What are adaptations?
Features that enable organisms to survive in their living environment.
What are organisms living in extreme environments called?
Extremophiles.
Give 3 examples of extreme living conditions.
High temperature.
High pressure.
High salt concentration.
State an example where extremophile bacteria can be found.
In deep sea vents.
What are 3 types of adaptations?
Structural - shape or colour.
Behavioural - ways an organism behaves.
Functional - processes that take place in an organisms body.
What are thermophiles?
Organisms that live at high temperatures.
What are halophiles?
Organisms that live in salty conditions.
What are barophiles?
Organism that live in high pressures.
What is biodiversity?
The variety of life that exists on Earth. (extinction leads to less biodiversity)
What is sustainability?
Using the Earth’s resources without damaging humans and the Earth for future generations.
What are 3 examples of environmental change?
A change in water availability.
A change in temperature.
A change in the composition of atmospheric gases.
What is food security?
Having enough food to be able to feed a population.
What are 4 biological factors threatening food security?
Rising birth rates.
New pests and pathogens.
Environmental changes affecting agriculture.
Conflict.
What are some intensive farming methods which increase the food production? (4)
Feeding animals high protein foods to increase growth.
Reduce energy loss by limiting movement and regulating surrounding temperature.
Feed them antibiotics to prevent disease.
Raising livestock in small cages (factory farming).
What are the advantages of intensive farming?
Higher yield of food.
More efficient.
What are some disadvantages of limiting the movement of livestock?`
Ethical concerns for animals quality of life.
Increased risk of injury and disease.
How can fish stocks be conserved?
Controlling size of gaps in fishing nets to prevent juvenile fish being killed before reaching reproductive maturity.
Fishing quotas.
Why might crops be genetically modified?
To improve nutritional value.
To become pest resistant.
To be pesticide resistant.
What is a transgenic organism?
An organism that has been genetically modified to contain genetic material from another source.
What is an example of a genetically modified food?
Golden rice.
What is an advantage of golden rice?
Contains beta-carotene which can be converted into vitamin A to help prevent night blindness from forming.
Can help people who do not obtain enough vitamin A.
What is a mycoprotein?
A protein-rich substance used as meat alternative for vegetarians and vegans.
How is mycoprotein produced?
Fusarium (fungus) is grown on glucose syrup, in aerobic conditions.
Biomass is harvested and purified.
Why does limiting the movement of livestock increase food production?
More of the food they eat gets turned into biomass instead of having to be use for respiration when an animal moves.
Why does keeping livestock in a temperature controlled environment increase food production?
Animals do not have to use as much energy for keeping warm or cooling down, leaving more energy for growth.
What are some disadvantages of keeping livestock in a temperature controlled environment?
High cost.
Fossil fuel used to heat.
Why does factory farming for fish increase food production?
Fish mature quicker - as move around less.
What are some disadvantages of factory farming?
Ethical objections for quality of life.
Faster spread of disease.
Why does feeding animals high-protein foods increase food production?
Increases the growth rate of the livestock.
More eggs produced.
What are some disadvantages of feeding animals high protein foods?
Feeding animals to animals means there is an extra stage in the food chain, making the energy transfer less efficient.
Unethical.
What do food chains show?
The feeding relationships of different organisms and the flow of energy between organisms.
Describe a simple food chain.
producer -> primary consumer -> secondary consumer -> tertiary consumer.
Describe the pattern between predators and prey in a stable community.
The number of predators and prey rise and fall in cycles.
Why are producers important?
They provide all the biomass for the food chain. The rest of the food chain involves the transfer of this biomass.
What piece of equipment is used to show the abundance and distribution of organisms in an area?
Quadrat
What piece of apparatus is used to study the distribution of organisms across a gradient?
Belt transect.
Give 3 molecules that are cycled through ecosystems.
Oxygen, carbon dioxide and water.
Describe the carbon cycle.
Plants fix C02 into organic molecules during photosynthesis.
The organic carbon-containing molecules are passed onto organisms that eat the plants.
CO2 released back into the atmosphere by respiration.
Burning fossil fuels also releases CO2.
Why is the carbon cycle important?
Carbon-containing 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.
Evaporated water condenses into clouds and returns to earth as precipitation.
Water used for life on land.
Water returns to rivers and oceans through surface runoff.
Why is the water cycle important?
Organisms require water and the water cycle provides organisms with a continuous supply of water.
Why are microorganisms important for cycling materials through an ecosystem?
Bacteria and fungi release C02 by respiration when they decompose matter.
The decomposition of dead matter in soil returns mineral ions to the environment for other organisms to use.
What is meant by decomposition?
The breakdown of dead materials into simpler organic matter.
How do decomposers break down dead matter?
Release enzymes which catalyse the breakdown of dead material into smaller molecules.
What are the 2 types of decomposition.
Aerobic decomposition.
Anaerobic decomposition.
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 oxygen availability affect the rate of decomposition?
Oxygen levels are directly proportional to the rate of decomposition.
Why can decomposition still occur in the absence of oxygen?
Some decomposers respire anaerobically.
What is the difference in the rate of decomposition for anaerobic and aerobic decomposition?
Anaerobic decomposition is slower as anaerobic decomposition produces less energy.
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 available for respiration, so rate decreases.
Why does decomposition require water?
For the secretion of enzymes and absorption of dissolved molecules.
What is the optimum temperature for enzymes?
50 degrees celcius.
How does temperature affect the rate of decomposition?
Rate highest at 50 degrees celcius.
Lower temperatures, enzymes work too slowly.
High temperatures, enzymes denature, decomposition stops.
How is rate of change calculated when considering the decay of a biological material?
Rate of change = change in value / change in time
What is compost?
The nutrient-rich product of the rapid decay of waste biological material.
How is compost used?
Used as a natural fertiliser to promote growth of plants.
How do biogas generators work?
They provide methane gas for fuel through anaerobic decomposition that occurs in animal waste.
What is the consequences on a community if temperature is too low?
Growth will be slower as organisms will use more energy to stay warm.
What is the consequences on a community if temperature is too high?
Organisms can die and water will become limited as evaporation increases.
How can changes in water levels affect ecosystems?
Animals 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 impact does sulfur dioxide have on the environment?
Erodes buildings.
Pollute water sources.
Kills plants.
How is sulfur dioxide formed?
When fossil fuels containing impurities are burnt and then dissolved in water.
How is carbon monoxide formed?
Incomplete combustion of fossil fuels.
What impacts does carbon monoxide have?
Binds to haemoglobin which prevents it from carrying oxygen.
Can cause unconsciousness and death with too much exposure.
Name 5 greenhouse gases.
Water vapour.
Carbon dioxide.
Nitrous oxide.
Methane.
CFC’s.
What are CFC’s?
Chemicals called chlorofluorocarbons, which are made up of chlorine, fluorine and carbon atoms.
Give 3 human activities that contribute to greenhouse gases?
Burning fossil fuels.
Deforestation.
Intensive livestock farming.
State 3 consequences of global warming.
Sea level rise.
Disrupts farming and agriculture.
Increased spread of diseases in warmer climates.
Why is biodiversity important?
To maintain the stability of an ecosystem.
How does biodiversity ensure the stability of an ecosystem?
It reduces the dependence on a particular species for resources (food), so if one species is removed other species can still survive.
Give 2 reasons why humans consumption of resources and waste production have increased.
Increase in population.
Increase in standard of living.
3 places pollution can occur.
Air
Land
Water.
3 examples of water pollutants.
Sewage.
Fertiliser.
Chemicals.
What is eutrophication?
Eutrophication is a type of water pollution caused by the addition of sewage or fertiliser.
Describe the process of eutrophication.
Water polluted by fertiliser from farms.
Causes excessive algae growth due to nitrates and mineral ions.
Depleting oxygen in the water, causing plants and animals to die.
Dead plants are decomposed by bacteria and oxygen level decreases further.
2 examples of air pollutants.
Smoke
Acidic gases.
2 examples of land pollutants.
Landfill waste.
Chemicals.
4 human activities that reduce the land available for animals and plants.
Building
Farming
Quarrying
Disposing waste
Why have peat bogs been destroyed?
To produce compost to increase food production.
Why does the destruction of peat bogs contribute to the greenhouse effect?
Peat bogs are stores of carbon (carbon sinks) and burning them releases a large volume of carbon dioxide into the atmosphere.
2 reasons why large-scale deforestation has occurred?
to provide land for cattle or rice fields.
to grow crops to produce biofuels.
2 harmful effects of deforestation.
Destruction of animals’ habitats.
Less greenhouse gases taken in from atmosphere.
6 consequences of global warming.
Rising sea levels.
Melting ice caps.
Changing weather patterns.
Migration of animals to find suitable habitats.
Extinction of species.
Increase in tropical diseases.
6 steps to maintain biodiversity.
breeding programmes for endangered species
protecting and rebuilding habitats
replanting hedgerows
reducing deforestation
reducing CO2 emissions
recycling
What is the purpose of replanting hedgerows and field margins?
There is a higher biodiversity in the margins than in fields that they surround.
How does industrial waste effect the environment/organisms?
Takes up lots of room destroys natural habitats.
Toxic chemicals poison soil.
Pesticides and weed killers kill animals and plants and poison the soil.
What are the disadv. of breeding programmes?
Many animals and plants don’t produce easily.
Habitats that organisms need to survive has been lost.
What are the disadv. of reintroducing hedgerows?
Less space for food, can mean less food security.
How did the Costa Rican government help biodiversity?
They protected the Costa Rican rainforest, after they realised it was under severe threat.
How are governments dealing with CO2 emissions?
Working with transport and electricity industries.
Name 3 harmful substances that cause water pollution.
Sewage
herbicides/fungicides
fertiliser
What are 2 disadvantages of rearing cows indoors?
Increased use of antibiotics.
Disease can easily be spread.
Aggressive behaviour causing harm.
