ecology Flashcards
What is the relationship between an individual, species, habitat, and population?
An individual is part of a species, but lives in its habitat within a population.
How are communities created?
- Many different populations interact in the same habitat, creating a community.
- The populations are often dependent on each other.
Define an ecosystem
- An ecosystem is the interaction of a community with non-living (abiotic) parts of the environment.
- Organisms are adapted to live in the conditions of their environment.
What happens when organisms need the same resources?
- Organisms which need the same resources compete for it.
- There can be competition within a species or between different species.
What may plants compete for?
- Plants may compete for light, space, water and mineral ions.
What may animals compete for?
- Animals may compete for space, food, water and mating partners.
Define interdependence
- Interdependence describes how organisms in a community depend on other organisms for vital services.
Give examples of interdependence
- These include for food, shelter and reproduction (pollination, seed dispersal), e.g.
birds take shelter in trees, flowers are pollinated with the help of bees.
What can the removal or addition of a species affect and why?
- The removal or addition of a species to the community can affect the populations of
others greatly, as it changes prey or predator numbers
Describe a stable community
- A stable community is one where all the biotic (living) and abiotic (non-living) factors
are in balance. - As a result the population sizes remain roughly constant.
- When they are lost it is very difficult to replace them.
Give examples of a stable community
- Tropical rainforests, oak woodlands and coral reefs
Define an abiotic factor
- An abiotic factor is a non-living factor
Name the abiotic factors which can affect a community
- Light intensity
- Temperature
- Moisture levels
- Soil pH and mineral content
- Wind intensity and direction
- Carbon dioxide levels for plants
- Oxygen levels for aquatic animals.
Explain the effect of light intensity on a community
- Light is required for photosynthesis.
- The rate of photosynthesis affects the rate at which the plant grows.
- Plants can be food sources or shelter for many organisms.
Explain the effect of temperature on a community
- Temperature affects the rate of photosynthesis.
Explain the effect of moisture levels on a community
- Both plants and animals need water to survive.
Explain the effect of soil pH and mineral content on a community
- Soil pH affects the rate of decay and therefore how fast mineral ions return to
soil (which are then taken up by other plants). - Different species of plants thrive in different nutrient concentration levels.
Explain the effect of wind intensity and direction on a community
- Wind affects the rate of transpiration (movement of water from root to leaves)
in plants. - Transpiration affects the temperature of the plant, and the rate of
photosynthesis because it transports water and mineral ions to the leaves.
Explain the effect of carbon dioxide levels on a community
- CO2 affects the rate of photosynthesis in plants.
- It also affects the distribution of organisms as some thrive in high CO2
environments.
Explain the effect of oxygen levels for aquatic levels on a community
- Levels in water vary greatly, unlike oxygen levels in air.
- Most fish need a high concentration of oxygen to survive.
Define a biotic factor
A biotic factor is a living factor.
Name the biotic factors which can affect a community
- Availability of food
- New predators arriving
- New pathogens
- One species outcompeting another so the numbers are no longer
sufficient to breed
Explain the effect of food availability on a community
- More food means organisms can breed more successfully and
therefore the population can increase in numbers
Explain the effect of new pathogens on a community
- When a new pathogen arises the population has no resistance to
it so they can be wiped out quickly
Explain the effect of competition on a community
- If one species is better adapted to the environment than another,
then it will outcompete it until the numbers of the lesser adapted species are
insufficient to breed.
How do organisms survive the conditions in which they normally live in?
- Organisms have features (adaptations) that enable them to survive in
the conditions in which they normally live.
What kind of adaptations can an organism have?
- These adaptations may be structural, behavioural or functional.
Define a structural adaption
- The shape or colour of a part of an organism
Give examples of structural adaptations and explain how they help an organism
- Sharp teeth of a carnivore to tear meat apart
- Camouflage, such as the tan/brown colour of a lionesses coat, to avoid prey
from spotting her - Species in cold environments may have a thick layer of fat for insulation
Define a behavioural adaption
- The way an organism behaves
Give examples of behavioural adaptations and explain how they help an organism
- Individuals may play dead to avoid predators
- Basking in the sun to absorb heat
- Courting behaviour to attract a mate
Define a functional adaptation
- Involved in processes such as reproduction and metabolism
Give examples of functional adaptation and explain how they help an organism
- Late implantation of embryos
- Conservation of water through producing little sweat
Define an extremophile
- Extremophiles are organisms that live in environments which have extreme conditions.
- These include high temperatures, pressures or salt concentrations.
Give an example of an extremophile
- An example is bacteria which live in deep sea vents where the pressure is very high.
Give an example of adaptations in cold climates and how they help an organism
- Smaller surface area to volume ratio to reduce heat loss, lots of insulation (blubber, fur coat)
Give an example of adaptations for dry climates and how they help an organis
- Adaptations to kidneys so they can retain lots of water producing very concentrated urine, being active in the early morning and evenings when it is cooler, resting in shady areas, larger surface area ratio to increase heat loss
Give examples of plant adaptations and how they help an organism
- Curled leaves to reduce water loss
- Extensive root systems to take in as much water as possible
- Waxy cuticle to stop water evaporating, water storing tissue in stem
What do food chains show?
- Feeding relationships are shown by food chains.
Describe the food chain
- They begin with a producer.
- Producers are eaten by primary consumers – energy is transferred through
organisms in an ecosystem when one is eaten by another. - Primary consumers are eaten by secondary consumers – The animals eaten are
called the prey and the consumers that kill and eat them are predators. - Secondary consumers are eaten by tertiary consumers.
Describe a producer
- These are always photosynthetic organisms (usually a green plant or algae)
How do producers make glucose and what is it used for?
- Through photosynthesis they make glucose
- Glucose is used to make other biological molecules in the plant, which make
up the biomass
How do you work out the distribution and abundance of species?
- To work out the distribution and abundance of species in an ecosystem, tools called transects and quadrats are used.
- You can then process this information by calculating the mean, mode and median and then drawing a graph.
What will a stable community show?
- A stable community will show population cycles between the predators and prey.
Explain how population cycles between predators and prey work
- If the population of prey increases, the population of predators will also increase.
- This will result in the number of prey decreasing after some time as more would be
consumed by the increased number of predators. - When there isn’t enough prey to feed all the predators, the population of predators will decrease, which will allow the population of prey to increase again
Name two cycles vital for life o earth
- The carbon and water cycles are vital for life on Earth.
- Lots of different materials are cycled through an ecosystem
Explain how the carbon cycle works
- CO2 is REMOVED from the air in photosynthesis by green plants and algae – they
use the carbon to make carbohydrates, proteins and fats. They are eaten and the
carbon moves up the food chain. - CO2 is RETURNED to the air when plants, algae and animals respire.
Decomposers (a group of microorganisms that break down dead organisms and
waste) respire while they return mineral ions to the soil. - CO2 is RETURNED to the air when wood and fossil fuels are burnt (called
combustion) as they contain carbon from photosynthesis
Explain how the water cycle works
- The sun’s energy causes water to evaporate from the sea and lakes, forming water
vapour. - Water vapour is also formed as a result of transpiration in plants.
- Water vapour rises and then condenses to form clouds.
- Water is returned to the land by precipitation (rain, snow or hail), and this runs into lakes to provide water for plants and animals.
- This then runs into seas and the cycle begins again
Name the factors that affect the rate of decomposition
- Temperature
- Water
- Availability of oxygen
How does temperature affect the rate of decomposition?
- Chemical reactions generally work faster in warmer conditions, but if
it is too hot the enzymes can denature and stop decomposition.
How does water affect the rate of decomposition?
- Microorganisms grow faster in conditions with water as it is needed for
respiration. Water also makes food easier to digest.
How does availability of oxygen affect the rate of decomposition?
- Most decomposers respire aerobically
How is compost produced?
- When biological material decays it produces compost
What is compost used for and why?
- It is used by gardeners and farmers as a natural fertiliser.
- To do this they have to provide optimum conditions for decay.
- If more oxygen is available they respire aerobically, producing heat.
- The increased temperature increases the rate of decay so the compost is
made quicker.
How is methane gas produced?
- Microorganisms decompose waste anaerobically to produce methane gas
What is methane gas used for?
- This can be burnt as a fuel.
What are biogas generators used for?
- Biogas generators are used to produce methane.
What are the requirements for a biogas generator?
- Require a constant temperature (30 degrees) so the microorganisms keep
respiring.
Why must the methane produced by a biogas generator be used immediately?
- It cannot be stored as a liquid so needs to be used immediately.
Explain how you can investigate the effects of temperature on decay
- You can investigate the effects of temperature on decay by measuring the pH change of fresh milk in the presence of the enzyme lipase.
1) Make a solution of milk and phenolphthalein indicator.
2) Add sodium carbonate which will cause the solution to become alkaline and
therefore appear pink.
3) Place the tube in a water bath at a specific temperature.
4) Add the lipase enzyme and begin stopwatch.
5) Time how long it takes for the pink colour to disappear (i.e. when the pH has
decreased).
6) Repeat this at different temperatures to see at which temperature the pink colour
disappears the quickest, indicating the quickest decomposition.
Name the environmental changes that affect the distribution of species in an ecosystem
- Temperature
- Water availability
- Atmospheric gas composition
How does temperature affect the distribution of species in an ecosystem?
- Climate change may lead to insects migrating to places in the
world which are becoming hotter
How does water availability affect the distribution of species in an ecosystem?
- Populations will migrate to find water
How does atmospheric gas composition affect the distribution of species in an ecosystem?
- Certain pollutants can affect the distribution of organisms
e.g. lichen cannot grow in places where sulfur dioxide is present.
What may these environmental changes that affect the distribution of species in an ecosystem be?
- These changes may be seasonal, geographic or caused by human interaction.
Define biodiversity
- The variety of different species of organisms on Earth or within an
ecosystem.
What does a high biodiversity mean and why is it good?
- High biodiversity means the ecosystem will be stable.
- Biodiversity means that species are less dependent on each other for things such
as food and shelter.
Do human activities have a negative or positive effect on biodiversity?
Many human activities are having a negative effect on biodiversity
What does the future of humans on Earth depend on?
The future of humans on Earth depends on maintaining biodiversity – for example for food
and new medicines.
What is happening as the population is increasing?
- The impact of our activities is getting bigger as the population is increasing
- As more resources are being used and more waste is being produced.
● Pollution kills plants and animals.
○ Sewage, fertiliser and toxic chemicals pollute the water.
○ Smoke and acidic gases pollute the air.
○ Landfill and toxic chemicals can result in the pollution of the land.
● Pollution kills plants and animals.
○ Sewage, fertiliser and toxic chemicals pollute the water.
○ Smoke and acidic gases pollute the air.
○ Landfill and toxic chemicals can result in the pollution of the land.
- We are using up raw materials quicker than they are being produced.
- Humans have only recently tried to reduce their impact.
How does human taking up land affect biodiversity?
- Humans take up land and therefore reduce the number of habitats for animals and plants
by building, quarrying (cutting into ground to obtain stone and other materials), farming
and dumping waste.
What is peat?
- Peat is a material that forms when plant material has not fully decayed as there is
not enough oxygen.
Where does peat accumulate?
- It accumulates in bogs that are acidic and waterlogged.
What are bogs used for?
- These bogs are a habitat for many species, in particular for migrating birds
Why are peat bogs being destroyed and what is the effect?
- They are being drained in order to create space for farming, peat is used as compost, or dried to use as fuel as it contain carbon (releasing CO2
into the atmosphere). - It is being used up quicker than it is being formed, as the formation process is slow.
Define deforestation
- The cutting down of a large number of trees in the same area, in order to use the land for something else.
Why does deforestation occur in tropical areas?
- To provide land for cattle and rice fields
- To grow crops (e.g. sugarcane, maize) for biofuels which are used to produce
energy
What are the problems that are caused by deforestation?
- As trees contain carbon, burning them results in more CO2 being released into the
environment which contributes to global warming. - Following deforestation, microorganisms decompose the dead vegetation, producing CO2 as they respire.
- Trees take in CO2 when they photosynthesise, so less trees means less CO2 is
taken in. - The number of habitats are reduced, decreasing biodiversity.
What does the term global warming refer to?
- The term global warming refers to the fact that the temperature around the world is increasing.
Why is the temperature around the world increasing?
- This is because we are producing more greenhouse gases (carbon dioxide
and methane), resulting in more heat being absorbed and reflected back to Earth, heating it up.
What are the consequences of temperature increase?
- Melting of the ice caps, reducing habitats
- Rising sea levels, reducing habitats as low lying areas will be flooded with salty
water - Temperature and rainfall levels will affect migration and therefore the distribution of different species, as they may no longer be able to survive where they live
- Organisms will become extinct as their habitats are lost, reducing biodiversity
What are the positives of human interactions with ecosystems?
- Maintaining rainforests, ensuring habitats here are not destroyed
- Reducing water pollution and monitoring the changes over time.
- Preserving areas of scientific interest by stopping humans from going there.
- Replanting hedgerows and woodlands to provide habitats which were previously
destroyed.
What are the negatives of human interactions with ecosystems?
- Production of greenhouse gases leading to global warming.
- Producing sulfur dioxide in factories which leads to acid rain – affects habitats
- Chemicals used in farming leak into the environment.
- Clearing land in order to build on, reducing the number of habitats.
Name ways in which we could reduce our negative impact on ecosystems to maintain biodiversity
- Breeding programs
- Protection of rare habitats
- Reintroduction of hedgerows and field margins around land where only one type of crop is grown
- Reduction of deforestation and carbon dioxide production
- Recycling rather than dumping waste in landfill
How do breeding programs reduce our negative impact on ecosystems to maintain biodiversity?
- To stop endangered species from becoming extinct.
How does the protection of rare habitats reduce our negative impact on ecosystems to maintain biodiversity?
- To stop the species here from becoming extinct, if damaged they may even be regenerated to encourage populations to live here
How does the reintroduction of hedgerow and field margins reduce our negative impacts on ecosystems to maintain biodiversity?
- Maintains biodiversity as the hedgerows provide a habitat for lots of organisms (because a field of one crop would not be able to support many organisms) and field margins provide areas where wild flowers and grasses can grow.
How does the reduction of deforestation and CO2 reduce our negative impact on ecosystems to maintain biodiversity?
- Reduces the rate of global warming, slowing down the rate that habitats are destroyed
How does recycling help reduce our negative impact on ecosystems to maintain biodiversity?
- Reduces the amount of land taken up for landfills, and slows the rate we are using up natural resources
Define trophic levels
- Trophic levels are the different stages in the food chain
What are trophic levels represented by?
- They are represented by numbers
What happens at Level 1 in the food chain?
- Organisms at the first level are called producers such as plants and algae.
- They make their own food by photosynthesis.
What happens at Level 2 in the food chain?
- Organisms at the second level are called primary consumers.
- These are herbivores that only eat plants.
What happens at Level 3 in the food chain?
- Organisms at the third level are called secondary consumers.
- These are carnivores and they eat herbivores.
What happens at Level 4 in the food chain?
- Organisms at the fourth level are called tertiary consumers.
- These are carnivores that eat other carnivores.
- They have no predators and are at the top of the food chain – called apex predators.
What is the function of a decomposer?
- Decomposers break down dead plant and animal matter.
What do pyramids of biomass show?
- Pyramids of biomass show the relative biomass at each trophic level
- It shows the relative weights of material at each level.
- There is less biomass as you move up the trophic levels.
- Not all the food consumed by an animal is converted into biomass – this means the biomass of the organism in the level above another will always be higher, as not all the organism can be consumed and converted into biomass.
What percentage of incident energy do producers transfer and why?
- Producers (e.g. plants and algae) transfer about 1% of the incident energy from light for photosynthesis, as not all the light lands on the green (photosynthesising) parts of the plant.
How much of the biomass of each trophic level is transferred to the next?
- Only approximately 10% of the biomass of each trophic level is transferred to the next.
Explain why so little biomass is transferred from one trophic level to the next
- Not all biomass can be eaten
- Carnivores cannot generally eat bone, hooves, claws and teeth.
- Not all of the biomass eaten is converted into biomass of the animal eating it.
- Lots of glucose is used in respiration, which produces the waste product carbon dioxide
- Urea is a waste substance which is released in urine
_ Biomass consumed can be lost as faeces - Herbivores do not have all the enzymes to digest all the material they
eat, so it is egested instead
How do you calculate the efficiency of biomass transfers?
Efficiency of biomass transfers: (Biomass transferred to the next level / Biomass
available at the previous level) x 100
Why is it common to find less animals in the higher trophic levels?
- Because less biomass is transferred each time it is common to find less animals in the higher trophic levels
Define food security
- Having sufficient food to feed the population
What are the factors that affect food security?
- Increasing birth rate
- Changing diets in developed countries
- New pests and pathogens
- Climate change
- Conflicts
How does increasing birth rate affect food security?
- Increasing birth rate means more food is required
How do changing diets affect food security?
- Changing diets in developed countries means food resources which are already in
low amounts become even more scarce as the demand for them increases.
How do new pests and pathogens affect food security?
- New pests and pathogens can destroy crops
How does climate change affect food security?
- Climate change affects food production (such as no rain resulting in crops failing).
How does conflict affect food security?
- Conflicts in some countries can affect the availability of water and food
To feed everyone on Earth ________ methods are needed
To feed everyone on Earth sustainable methods are needed.
What do farmers aim to do to be more efficient?
- Farmers aim to increase the amount of energy (from food) that is converted to
biomass in livestock because this is more efficient.
How are farmers increasing the amount of energy that is converted to biomass in livestock?
- This is done by reducing the energy transfer from the animals to the environment.
- Raising them in small cages so there is less movement and therefore less
energy wasted on this - Areas where they are kept have high temperatures so less energy is wasted
on controlling body temperature - To increase growth they are also given high protein foods
What are the problems with this farming (that increase the amount of energy that is converted to biomass in livestock)?
- This type of farming has many ethical objections because lots of animals are kept in a small place , causing distress.
- It also increases the risk of spread of infection.
- It is carried out to increase profit and efficiency, but the standard of living is very low for the animals.
The number of fish in the oceans are ___________.
- The number of fish in the oceans is decreasing.
Explain why the number of fish in the oceans are decreasing
- This is because humans are fishing at a faster rate than the populations can
regenerate.
Explain how we can stop the number of fish in the oceans from decreasing
- To avoid species disappearing in some areas, the populations need stay above a
certain level so breeding can continue. - Some restrictions have been put in place:
- There are limits of net sizes (making them bigger) so smaller fish are not caught and can reach breeding age and produce more fish.
- Fishing quotas mean only a certain number of a species of fish can be caught (in an area and over a time period) to prevent overfishing.
What can biotechnology be used for?
- Biotechnology can be used to help feed the population and potentially provide treatments for a number of diseases
What can the fungus Fusarium produce and what is it used for?
- The fungus Fusarium can produce mycoprotein.
- Used as a food source
Why is Fusarium a suitable food source?
- Protein-rich food source
- Suitable for vegetarians
- Protein without animals
How is Fusarium grown and used as a food source?
- Grown on glucose syrup in aerobic conditions
- The fungus is harvested and purified so it can be consumed
What can genetically modified bacteria produce and what is it used for?
- Genetically modified bacteria produces insulin
- The insulin is taken and purified and then used to treat people with diabetes
What can genetically modifying crops do?
- Genetically modifying crops can make them have certain properties can have many advantages
What are the advantages of genetically modifying crops?
- Modifying them to be resistant to pests or extreme weather conditions can
increase yields - Modifying them to increase their nutritional value is beneficial in places
where they lack access to certain vitamins (such as ‘Golden rice’)
How does Fusarium positively impact our environment?
- Reduces land use, as a lot of land is required to rear animals and also
areas to grow crops to feed them. - Reduces our methane contribution (because cows produce methane)
