B8: Ecology Flashcards
Self supporting [definition]:
When all the requirements to survive are present
Interdependence [definition]:
When organisms depend on each other for survival
Ecosystem [definition]:
The interaction of the community and the habitat
Community [definition]:
A group of living organisms
Population [definition]:
The total number of individuals in one species
Biodiversity [definition]:
The range of plant and animal species
Habitat [definition]:
The place an organism lives
What is a stable community?
Where biotic and abiotic factors are in balance so the population sizes remain fairly constant
The predator population is always…
Lower than the prey population
Biotic factors [4]:
- Food availability
- Predators
- Pathogens
- Competition
Abiotic factors [6]:
- Temperature
- Oxygen
- Carbon dioxide
- Moisture
- pH
- Wind
Abiotic [definition]:
Non-living
What is the smallest part of an ecosystem?
Individual organisms
What do animals compete for? [4]:
- Mates
- Food
- Territory
- Water
What do plants compete for? [3]:
- Water and mineral ions from the soil
- Light
- Space to grow
Interdependence between species [4]:
- A species may depend on another for food.
- A species may depend on another to spread its seeds
- A species may depend on another for pollination
- A species may depend on another for shelter.
When is a community stable?
When all the species and environmental factors are balanced and population sizes stay more or less constant
What do food chains show?
The feeding relationships within a community
Food chains [5]:
- Trophic level 1 = producer
- Trophic level 2 = primary consumer
- Trophic level 3 = secondary consumer
- Trophic level 4 = tertiary consumer
- Trophic level 5 = apex predator
What is an apex predator?
A predator that is at the top of the food chain
What does a predator-prey graph show?
They show the cyclical nature of predator and prey populations in stable communities
What is a classic example of a cyclical relationship between predator and prey?
The Canada lynx and snowshoe hare
How do environmental changes impact ecosystems?
Environmental change affects the distribution of species, and in extreme cases, their longevity
Types of environmental changes [3]:
- Water
- Temperature
- Atmospheric gases
What is an example of how water impacted an ecosystem?
Wildebeests migrate annually from the Serengeti plains of Tanzania Northwards into Kenya to track seasonal changes in rainfall patterns.
What is an example of how temperature impacted an ecosystem? [2]
- Polar bears hunt seals on floating sea ice.
- Increasing temperatures cause this ice to melt. This
means that the polar bears are no longer able to hunt
their main food source.
What is an example of how environmental gases impacted an ecosystem? [2]
- Carbon dioxide dissolves in water and increases the
water acidity. - Acidic water hinders corals’ ability to build a skeleton.
This means that the increased carbon dioxide in the
atmosphere prevents coral growth.
Causes of environmental change [3]:
- Seasons (dry season, wet seasons, spring winter)
- Geological activity (e.g volcanoes, storms and droughts)
- Humans (pollution, the building of dams, burning fossil fuels)
The industrial revolution and its relation to the population of moths [3]:
- In the industrial revolution (1750 -1850 in the UK), the number of peppered moths decreased
- The number of black moths increased
- The black moths were better adapted to the smoky polluted conditions and were better camouflaged
Name two experimental tools used to study ecosystems and their populations.
- Transects
- Quadrats
Transects [2]:
- A transect line is a piece of tape that is stretched across the habitat of interest
- They can be used to investigate the effect of a factor on a species
Quadrats [2]:
- Square frames that are used to estimate population sizes
- They are placed at regular intervals along the transect line
What are the metrics used for describing organism abundance? [3]:
- Mean
- Median
- Mode
How do you use quadrats to estimate population size?
[4]:
- Divide the habitat up into a series of quadrat-sized cells
- Randomly select a given number of cells, then go out into the habitat and place the quadrat in these positions
- Count the number of individual organisms of interest or record the percentage of the quadrat taken up by an organism
- The samples from the quadrat are used to estimate the total population in a given area
Population =
…………………………………..total survey area
number counted x —————————
……………………………………..area sampled
What two cycles are important for living organisms?
- Carbon cycle
- Water cycle
The carbon cycle (basics)
[2]:
- Carbon is present in all living organisms.
- When organisms die, the carbon is recycled so that it can
be used by future generations.
The water cycle (basics)
[2]:
- This cycle describes how water moves on, above or just below the surface of our planet between different locations
- In order for this cycle to be completed, water has to change state.
The carbon cycle [5]:
- Carbon is removed from the atmosphere by producers who use it in photosynthesis
- Animals obtain carbon compounds by consuming plant matter
- Carbon is returned into the atmosphere because of the respiration that happens in plant and animal cells
- Decomposers return the carbon locked in their bodies back to the atmosphere via decay
* Combustion of fossil fuels is another source of carbon entry into the atmosphere
The water cycle [4]:
- Water evaporates from the Earth’s surface, before rising up into the atmosphere
- Once in the atmosphere, the water vapour cools and condenses into either rain or snow
- The rain or snow will either become surface runoff or will travel through the earth as groundwater
- Plants take up water through their roots
Why does biological material decay?
Biological material in the form of waste products or dead organisms decays as a result of the activity of decomposers
What factors speed up the rate of the decay process?
[3]:
- High oxygen availability
- High moisture availability
- High temperatures
Biogas Generators [4]:
- A result of anaerobic decay is the production of biogas like methane
- Biogas generators produce methane gas, which is used as a fuel.
- It can also be used to produce slurry which can also be used as a fertiliser
- It is crucial that temperatures are maintained at a suitable level and that oxygen is not allowed to enter the site of fermentation
What are the two main products of biogas generators?
- Methane
- Slurry
Biogas generators [definition]:
Devices that can produce methane gas as a fuel for purposes such as cooking, heating or refrigeration
What do large scale biogas generators use as inputs?
[2]:
- Waste from sugar factories
- Waste from sewage works
What do small scale biogas generators use as inputs and where are they used?
[4]:
1) - Egested material from humans and animals
- Farm and garden waste
2) -Houses and farms
Investigating the effect of temperature on the rate of decay of fresh milk by measuring pH change (Method)
[5]:
- Use a water bath to heat all of the components to a given temperature.
- Mix the milk, sodium carbonate and Cresol red. The resulting solution should be purple.
- Add lipase to the solution and start timing.
- When the solution turns yellow, stop timing.
- Repeat using different temperatures.
Investigating the effect of temperature on the rate of decay of fresh milk by measuring pH change (observation)
[3]:
- The effect of temperature on the rate of decay can be observed using milk.
- As milk takes a long time to decay, lipase and sodium carbonate are added to speed up the decay.
- As milk decays, its pH reduces. This can be observed with an indicator called Cresol red.
Investigating the effect of temperature on the rate of decay of fresh milk by measuring pH change
(experiment variables) [2]:
- Independent variable = The temperature
- Dependent variable = Time taken for solutio to tur yellow
Which word best describes the nature of predator-prey dynamics in stable communities?
Cyclic
Over the course of many years, what happens to the population sizes of a predator and its prey?
They increase
What can slurry be used as?
Fertiliser
What do decomposers secrete to break down organic matter?
Enzymes
What type of sampling should be used when assessing ecosystems?
Random
How do ‘fallow years’ increase the yield of crops?
[4]:
- Legume plants have root nodules which contain nitrogen-fixing bacteria
- These bacteria have a mutualistic relationship with the plant and convert atmospheric nitrogen into ammonia
- Leaving leguminous plants to be decomposed by saprobionts is a form of natural fertiliser
- Leguminous plants have high levels of nitrate ions and this is returned to the soil when they are decomposed
Fallow year [definition]:
An agricultural practice in which a legume plant is NOT harvested but is left in the soil.
Humans and biodiversity [3]:
- Attitudes have recently begun to change and measures are being taken to prevent further damage being done and to regain pre-existing biodiversity.
- An awareness of the detrimental nature of these activities has existed for several decades.
However, because of the pursuit of economic gain, the warning signs have largely been ignored. - For some time, and especially since the industrial revolution, humans have conducted many activities that have caused a severe decline in biodiversity on a global scale.
Which revolution resulted in the initial spike in human activities that were detrimental to biodiversity?
The industrial revolution
Land pollutants [3];
- Toxic herbicides and pesticides used in farming
- Buried nuclear waste
- Household waste in landfill sites
Waste management in the air [2]:
- Smoke and air are added to the atmosphere constantly
- The main sources of these pollutants are cars and power stations
Water pollutants [2]:
- Sewage and toxic chemicals produced by industrial practices
- excess fertiliser from agriculture also pollutes the earth’s water sources
Peat [definition]:
A deposit of partially decayed plant matter which accumulates in bogs
Where is the carbon in peat?
Carbon remains in the plants instead of being released into the atmosphere.
The destruction of peat bogs [2]:
- The burning or decay of peat results in the release of the stored carbon into the atmosphere as carbon dioxide
- Peat bog destruction can also lead to the loss of biodiversity within the habitat
Why are peat bogs being destroyed? [3]:
- To free up land for farming
- To burn peat for fuel
- To sell peat to gardeners as garden compost
How do they destroy peat bogs to free up land for farming?
- Bogs have to be drained
- The draining process stimulates peat decay
How can we reduce the demand for peat?
Using peat-free compost like manure and bark chippings
What are the negative impacts of peat bog destruction?
[2]:
- Release of carbon dioxide
- Loss of biodiversity
Deforestation [definition]:
The cutting, clearing and removal of forests in order to free up land for biofuels as well as cattle and rice fields
Consequences of deforestation [5]:
- Destroyed habitats = loss of biodiversity
- A loss in ecosystem services provided by the forest
- The release of methane as forests are often replaced by rice plantations or land for farming cattle
- Burning of trees and decomposition of wood increases the rate of carbon dioxide released into the atmosphere
- Less photosynthesis is taking place as a result of the reduced population of trees and plants, so less carbon dioxide is taken from the atmosphere
What are some ecosystem services provided by the forest?
[3]:
- Erosion prevention
- Flood control
- Food provision
Peat bogs act…
as a store for carbon, preventing it from being released into the atmosphere
Carbon dioxide removal from the atmosphere [3]:
- It is removed naturally by plants and algae during photosynthesis
- It is dissolved into large bodies of water
- It is also stored in peat bogs
Carbon dioxide release into the atmosphere [4]:
- Released naturally into the atmosphere by respiration
- Decay releases it into the atmosphere
- Destruction of peat bogs releases it into the atmosphere
- combustion of fossil fuel releases it into the atmosphere
The greenhouse gas effect [4]:
- The greenhouse effect describes how greenhouse gases act as a natural, insulating layer in the atmosphere
- They re-radiate most of the heat energy which has been reflected off the Earth’s surface back towards Earth
- Climate scientists believe the greenhouse gas effect is causing global warming
- As the atmospheric concentrations of greenhouse gases rise, there is a risk that the greenhouse effect could become too strong and the temperature could rise too high
What are the primary greenhouse gases?
[5]:
- Carbon dioxide (CO2)
- Methane (CH4)
- Water vapour (H2O)
- Ozone (O3)
- Nitrous oxide (N2O)
Consequences of global warming [7]:
- Extreme meteorological events (floods, droughts, severe storms and wildfires) happen more often
- Malaria-carrying mosquitoes have spread to many European countries
- Reduction in biodiversity as large-bodied animals that have longer generation times can’t adapt quickly enough
- Migration patterns altered due to temperature change
- Melting ice
- Rising sea surface temperature
- Increasing acidification of the oceans makes it harder for corals to build skeletons
How are humans trying to maintain biodiversity?
[4]:
- Recycling
- Farmers are being incentivised to maintain field margins and hedgerows as these habitats can support biodiversity.
- Protection and regeneration of rare and threatened habitats
- Breeding programmes for endangered species
What are the benefits of recycling?
[2]:
- It slows down landfill expansion
- Reduces the need to extract natural resources
What happens as a result of melting ice?
[3]:
- sea levels rise
- leads to the flooding of coastal habitats
- Obfuscates the survival of animals on both poles
What does the rise in sea surface temperature cause?
The bleaching of sensitive corals
What is an example of government-imposed targets regarding deforestation and emission reductions?
[3]:
- The ambitious targets set by Brazil regarding the amazon rain forest:
- The complete abolishment of illegal deforestation
- The reforestation of twelve million hectares by 2030.
Which gases are released faster as a result of deforestation and land conversion to agriculture?
[2]:
- Methane
- Carbon dioxide
What is made when sulfur dioxide dissolves in moisture in the air?
Acid rain
What do trophic levels do?
An organism’s trophic level describes where it fits into a food chain
What comes at the base of all food chains?
Producers
What are decomposers responsible for?
Recycling organic matter within an ecosystem and represent the final stop for all food chains
What happens during decay?
[3]:
- Decomposers break down dead material by secreting enzymes.
- Enzymes partly digest the waste products, producing small and soluble food molecules.
- These small soluble molecules can then diffuse into the decomposer.
Name 2 decomposers:
- Fungi
- Bacteria
Biomass =
Total mass of living material x Number of organisms
Pyramids of Biomass:
A pyramid of biomass can be constructed to represent the relative amount of biomass at each trophic level in a food chain
Transfer of biomass [4]:
- Energy is wasted at each trophic level in a food chain, meaning less biomass and energy is passed on to the next organism in the food chain
- This progressive loss of energy usually means that there are fewer individuals at higher trophic levels
- Producers only manage to trap approximately 1% of light energy from the sun.
- Around 10% of energy is passed to the next trophic level
Reasons for Inefficient Transfer of Biomass
[4]:
- Some material is excreted: carbon dioxide and water in respiration; urea and water in urine.
- Not all food is digested. Some food is stored as the waste material faeces, before being egested.
- Large quantities of glucose are used in respiration to produce energy. Highly mobile animals require a lot of energy to sustain their movement.
- Warm-blooded animals need to expend energy to maintain suitable body temperatures.
Which trophic level tends to contain the most biomass?
Level 1
Food security [definition]:
When the whole global human population has access to enough safe and nutritious food to stay healthy
What are some obstacles to maintaining food security?
[6]:
- Increasing birth rates
- Diet shifts in developed countries are resulting in the accumulation of a massive quantity of food miles because food is transported across the world in order to meet demands.
- The increasing cost of agricultural inputs as farmers can only afford less which means the yield of crops is less
- Extreme meteorological events can damage harvests
- New pests and pathogens
- Conflicts often result in reduced access to food and water.
Biotechnology [definition]:
The use of biological processes to develop or make products
Mycoprotein [3]:
- A food source that is high in protein and fibre
- It is low in fats
- Suitable for vegetarians to consume
How is mycoprotein produced? [2]:
- It is produced by growing the fungus Fusarium in vats called fermenters under aerobic conditions and using glucose syrup as a food source.
- Eventually, the biomass is harvested, before finally being purified and used to make meat substitutes.
Genetic modification [3]:
- Genetically modified crops have the potential to provide more food, including more nutritious food.
- Golden rice is genetically modified to contain a molecule that helps make vitamin A.
- If distributed effectively, golden rice can play a significant role in reducing a large number of cases of vitamin A deficiency worldwide.
Examples of modern biotechnology techniques [2]:
- Mycoprotein production/growing microorganisms for food
- Genetic modification
What has golden rice been genetically modified to have?
A molecule that helps make vitamin A
Farming Techniques for Improving Food Production [3]:
- Feeding animals foods that are high in protein helps boost their growth rates.
- Livestock helps limit the amount of energy wasted, which helps produce food produce efficiency
- Shortening food chains
Why does shortening food chains help improve food production? [2]:
- Only about 10% of energy passes from each trophic level to the next.
- Therefore, shortening food chains will greatly increase efficiency.
How do high protein foods benefit animals?
They boost growth rates
Declining fish stock:
Overfishing has led to the drastic decline of many fish stocks across the globe
What are some of the consequences of declining fish stocks? [4]:
- Food chains to be affected
- Populations of fish to be at the risk of disappearing
- Food security is threatened
- Fishermen struggle to make enough money to support themselves
How do we combat overfishing?
[2]:
- Smaller fishing nets
- Fishing quotas
Fishing quotas [definition]:
Restrictions on the number and size of fish that can be legally caught
Sustainable fishing [definition]:
Fishing at levels which ensure that fish stocks do not dip below levels at which they continue to breed
What fungus is grown to produce Mycoprotein?
Fusarium
What has led to the drastic decline of many fish stocks across the globe?
Overfishing
