Unit 7 - Ecology Flashcards
State the levels of organisation in an
ecosystem.
Individual, population, community,
ecosystem.
What is an ecosystem?
The interaction between the living
components and non-living components.
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 interdependence?
Different species in a ecosystem depend
on each other for various resources, if
one species is removed, the whole
community may be affected.
What is a stable community?
A community in which all the biotic
factors (the different species) and all
abiotic factors are balanced so that
population sizes remain relatively
constant.
What are abiotic factors?
Non-living factors.
State the abiotic factors that may affect
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.
Why does temperature affect an
ecosystem?
Different species of plants and animals may
have different optimum temperatures for
growth and survival.
How does soil pH affect an ecosystem?
Certain plants may grow better in either
alkaline or acidic soil.
Soil pH may affect the appearance of the
plant eg. colour of hydrangea.
How does moisture level 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 wind intensity affect an
ecosystem?
Plant seeds are more likely to germinate in
locations with lower wind intensity, which may
also 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.
How does soil mineral content affect an
ecosystem?
Most plants require a high level of soil
minerals to grow well.
Give an example of a type of plants that
have adapted to low soil mineral content.
Carnivorous plants catch insects to
compensate 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
low oxygen concentration.
State the biotic factors that may affect an
ecosystem.
● Food
● New predators
● New pathogens
● Competition
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
environments.
● High temperature
● High pressure
● High salt concentration
State an example of where extremophile
bacteria can be found.
In deep sea vents.
Define population
A species that occupy the same habitat.
Define habitat
The place in which an organism lives.
Define community
Populations of different species
interacting.
Define ecosystem
The interactions between the biotic and
abiotic factors in an area.
What do food chains show?
Food chains show the feeding relationships of
different organisms and the flow of energy between
the organisms.
What do food chains show?
Food chains show the feeding relationships of
different organisms and the flow of energy between
the organisms.
Define biomass
The total mass of living material.
What are trophic levels?
The stages in a food chain.
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.
What types of organisms are primary
producers?
Photosynthetic organisms like green
plants and algae that trap energy from
the sun.
What is a Producer
An organism that makes its own food.
What is a primary consumer?
An organism that feeds on producers.
What is a secondary consumer?
An organism that feeds on primary
consumers.
What is a tertiary consumer?
An organism that feeds on secondary
consumers.
What is a predator?
A consumer that kills and eats other
animals.
What is prey?
An animal that is killed and eaten by
another animal
Describe the pattern of predators and
prey in a stable community
The numbers of predators and prey rise
and fall in cycles.
Why are producers the first trophic level?
● Producers provide all biomass for the food
chain (production of glucose via
photosynthesis).
● The rest of the food chain involves the transfer
of this biomass.
What piece of apparatus is used to
measure 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
When considering the abundance of
organisms, what is meant the term
“mean”?
The average number of organisms.
How is the arithmetic mean calculated?
Sum of each number of each
organism/the total number of each type
of organism
When considering the abundance of
different organisms, what is meant by the
term “mode”?
The most populous organism
When considering the abundance of
organisms, what is meant by the term
“median”?
The organism that represents the middle
value when the numbers of each
organism are arranged from lowest to
highest
Describe how materials cycle through
the living and non-living components of
an ecosystem
● Organisms take in elements from their surroundings e.g. soil, air.
● Elements converted to complex molecules which become biomass.
● Elements transferred along food chains.
● Elements returned to environment during excretion and
decomposition of dead organisms.
Give 3 molecules which are cycled
through ecosystems
Oxygen, carbon dioxide and water.
Describe the carbon cycle
- Plants fix carbon dioxide into organic molecules during
photosynthesis. - The organic carbon-containing molecules are passed onto 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 into the atmosphere.
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.
- The evaporated water condenses into clouds and returns
to earth as precipitation. - The water from precipitation is useful for life on land.
- The water then returns to rivers and oceans through
surface runoff.
Why is the water cycle important?
Living organisms require water and the
water cycle provides organisms on land
with a continuous supply of water.
Why are microorganisms important for
the cycling of materials through an
ecosystem?
Microorganisms (bacteria and fungi) 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 e.g. plants use
mineral ions for growth.
Why are microorganisms important for
the cycling of materials through an
ecosystem?
Microorganisms (bacteria and fungi) 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 e.g. plants use
mineral ions for growth.
How can different temperatures be bad
for certain communities?
- If the temperature is too low, growth will be slower
as organisms will use more energy to stay warm - If the temperature is too high, organisms can die
and water will become limited as evaporation
increases
How can changes in water levels affect
ecosystems?
- Animals may have to migrate to find water.
- Melting ice caps may destroy the habitats of
some animals (either animals living in icy
regions or by sea level rise).
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 detrimental impacts can sulfur
dioxide have on 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.
What detrimental impacts can carbon
monoxide have on 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. - Too much exposure can cause unconsciousness and
death.
Name 5 greenhouse gases
- Water vapour
- Carbon dioxide
- Nitrous oxide
- Methane
- CFCs
Give 3 human activities that contribute to
greenhouse gases
- Burning fossil fuels
- Deforestation
- Large scale livestock farming
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.
State 3 negative consequences of global
warming
- Sea level rise caused by melting icebergs.
- Disrupted farming and agriculture.
- Increased spread of diseases in warmer
climates.
What is biodiversity?
The variety of the different species on
earth or within an ecosystem.
What is the importance of biodiversity?
To maintain the stability of an ecosystem.
How does biodiversity ensure the
stability of an ecosystem?
It reduces the dependence on particular
species for resources eg. food and shelter, so
that even if one species is removed other
species can still survive.
Why have humans’ consumption of
resources and waste production
increased?
● Rapid rise in human population
● Increase in standard of living
Where does pollution occur?
● Air
● Land
● Water
State an example of water pollutants
● Sewage
● Fertiliser
● Chemicals
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
level decreases further.
State an example of air pollutants.
● Smoke
● Acidic gases
State an example of land pollutants.
● Landfill waste
● Chemicals
State an example of land pollutants.
● Landfill waste
● Chemicals
Which human activities reduce the land
available for animals and plants?
● Building
● Farming
● Quarrying
● Disposing of waste
Why have peat bogs been destroyed?
To produce compost to increase food
production.
Why does the destruction of peat bogs
greatly 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.
Why have large-scale deforestation
activities occurred?
● To provide land for cattle or rice fields
● To grow crops to produce biofuels
What is the greenhouse effect?
Greenhouse gases trap energy from the
Sun as heat in the atmosphere, keeping
the temperature on earth suitable for life.
What is causing global warming?
The increase in levels of greenhouse
gases eg. carbon dioxide and methane,
causing the temperature on earth to
increase.
What are the harmful effects of
deforestation?
● Destruction of many animals’ habitats
● Releases large amounts of
greenhouse gases
State the consequences of global
warming.
● Rising sea levels
● Melting polar ice caps
● Changing weather patterns
● Migration of animals to find suitable habitats
● Tropical diseases becoming more common
● Extinction of species
Describe the steps taken to maintain
biodiversity.
● Breeding programmes for endangered species.
● Protection and rebuilding habitats.
● Replanting field margins and hedgerows.
● Reduce deforestation.
● Reduce carbon dioxide emissions.
● Recycling rather than disposing in landfills.
What is the purpose of replanting
hedgerows and field margins?
There is higher biodiversity in the
margins than the fields that they
surround.
