Ecology Flashcards
What is ecology?
The study of how living things relate to each other and to their environment
What is an environment?
An environment refers to all the conditions in which the organism lives, which affect the growth and development of the organism
What is an ecosystem?
An ecosystem is a community of living organisms interacting with one another and their non-living environment within a particular area
Name a true ecosystem and why it is one?
The earth itself is a true ecosystem as no part of it is completely isolated from the rest
Why is a true ecosystem a true ecosystem?
no part of it is completely isolated from the rest
What is an ecosystem made up of?
Communities + Environment
Can ecosystems be quite large?
yes
Give some examples of ecosystems?
Woodland, hedgerow, seashore, marine, grassland, freshwater, tree
What is an ecosystem divided into?
A number of smaller, more manageable areas (habitats)
What do we do after we divide the ecosystem into manageable areas?
Study individual habitats
What is the biosphere?
That part of the earth inhabited by living organisms, including land, ocean and the atmosphere in which life can exist
What is another name for the biosphere?
The global ecosystem
What is the biosphere composed of?
Upper atmosphere, air, water, land and soil, Earth’s mantle
What is the biosphere made up of?
ecosystems
What are ecosystems made up of?
communities of organisms and the environment
What are communities made up of?
Populations of different species of organisms
What is a habitat?
A habitat is the particular place within the ecosystem where an organism lives and to which it is adapted
What is a simple definition of a niche?
A niche is the functional role of an organism in an ecosystem
What is an explanation of a niche?
A niche is a term describing the relational position of a species or population in an ecosystem including how it responds to the abundance of resources and enemies and how if affects the same factors.
What is an example of how a population responds to the abundance of resources and enemies?
By growing when resources are abundant, and predators, pathogens and parasites are scarce
Why is the non-living environment part of the niche and what is it called?
The abiotic or physical environment is part of the niche because it influences how populations affect, and are affected by, resources and enemies
What may a description of a niche include?
Descriptions of an organisms life history, habitat and place in the food chain
What are abiotic factors?
These are non-living features of an ecosystem (i.e. the physical and chemical conditions) that affect the community
What are biotic factors?
These are living factors of an ecosystem that affect the other members of a community
What are climatic factors?
These are the average weather conditions that affect the community in an ecosystem
What are edaphic factors?
These refer to the soil and are the physical, chemical and biological characteristics of the soil that influence the community
How long can two species occupy the same niche in the same environment?
not for a long time
What can happen when plants and animals are introduced to a new environment
They can occupy new niches, or niches of native organisms, outcompete the native species, and become a serious pest
Name some biotic factors
Plants for food and shelter, predators, prey, parasites and pathogens, decomposers, competitors, pollinators
Name some climatic factors
Temperature, rainfall, humidity, wind, light intensity (including seasonal variations), day length
For a species to maintain it’s population what must happen?
It’s individuals must survive and reproduce
Name some edaphic factors
Soil type, soil pH, available (soil) water, air and mineral content, humus, soil texture and structure
Name some aquatic environmental factors
Light penetration, currents, wave action
What are necessary for individuals of each species to tolerate the physical environment, obtain energy and nutrients, and avoid predators?
Certain combinations of environmental conditions
What determines where a species can live and how abundant it can be at any one place? What are these called?
The total requirements of a species for all resources and physical conditions. These requirements are termed the ecological niche.
Give examples of abiotic factors
Temperature, light intensity, air speed, water current, humidity, pH, dissolved oxygen, salinity, nitrate, phosphate and other plant nutrients.
What does the sun do?
The sun is the primary source of energy for our
What is energy flow?
The pathway of energy transfer from one organism to the next in an ecosystem due to feeding, e.g. along a food chain.
What does feeding do?
Allows energy to flow from one organism to another in an ecosystem.
What is the food chain?
A flow diagram that begins with a plant and shows how food/energy is passed through a series of organisms in a community. Each organism feeds on the one before it.
What does an organism feed on in the food chain?
the one before it
When does a food chain end?
When there is not enough energy to support another organism
Give an example of a food chain
grass -> rabbit -> fox
What is a detritus food chain?
One where the chain begins with dead organic matter and animal water (detritus)
Give two examples of detritus food chains
Detritus -> edible crab -> seagull
Fallen leaves -> earthworms -> blackbirds -> hawks
What is a food web?
a chart showing all the feeding connections in the habitat/ecosystem
how is a food web constructed?
by showing the links between all the interconnecting food chains in the habitat
What are producers?
Producers are organisms capable of making their own food by photosynthesis, e.g. green plants.
What are primary producers?
Primary producers are the first members of a food chain
What are consumers?
Organisms that feed on other organisms. They cannot make their own food.
What do primary consumers do?
feed on producers
What do secondary consumers do?
feed on primary consumers
What do tertiary consumers do?
feed on secondary consumers
What is the trophic level?
This refers to the position of an organism in a food chain.
What is the pyramid of numbers?
A diagram that represents the numbers of organisms at each trophic level in a food chain
Bottom layer of the pyramid of numbers
The bottom layer is the largest and represents a smaller number of primary consumers.
The second layer (from bottom) of the pyramid of numbers
This layer is smaller and represents a smaller number of primary consumers.
The third layer (from bottom) of the pyramid of numbers
represents the number of secondary consumers
The uppermost layer of the pyramid of numbers
Where there may be only one tertiary consumer
How do you construct a pyramid of numbers?
- Count the primary producers and place them at the base of the pyramid. 2. Count each consumer and include them according to their status (primary or secondary consumer) in the pyramid. 3. The apex of the pyramid should include tertiary or top carnivores. 4. Draw the pyramid so that the area/volume of each level is proportional to the number of organisms found.
What does nutrient recycling do?
This ensures that there is no real longterm drain on the Earth’s nutrients, despite millions of years of plant and animal activity.
What is nutrient recycling?
Nutrient recycling is the way in which elements are continuously being broken down and/or exchanged for reuse between the living and non-living components of an ecosystem.
What is CO2 in the atmosphere used for?
Photosynthesis by plants
After plants use up CO2 through photosynthesis, what happens to it?
Respiration - and then back to the atmosphere
Eaten and assimilated - By animals
Decays - and is then eaten by decomposers
Turns into fossil fuels - under certain conditions
After CO2 becomes a fossil fuel what happens?
It may return to the atmosphere through combustion
After decomposers eat the dead plants and and then have the CO2, what happens?
It goes back to the atmosphere through repiration
After animals eat plants and take in CO2 what happens?
It goes back to the atmosphere through respiration or is eaten by decomposers when the animal dies
Why do organisms need nitrogen?
All organisms need nitrogen for protein, DNA and RNA manufacture
how much of Earth’s atmosphere is nitrogen gas and what can this gas not be used for?
78% of the Earth’s atmosphere is nitrogen gas, but it cannot be used in this form by plants and animals
What must happen to nitrogen gas before it can be used by plants and animals?
nitrogen gas must be “fixed” e.g. changed to a suitable form (ammonia or nitrate) before it can be used
What are nitrogen fixing bacteria?
Nitrogen fixing bacteria in the soil convert N2 gas in the air into ammonia (NH3). This accounts for the majority of all N2 fixation.
What do lightning storms and fuel burning in car engines do?
produces nitrates which are washed by rain into the soil water
What are nitrates used for?
Nitrates are absorbed by plant roots and converted to plant protein
What happens to plant proteins?
They are passed along the food chains to become animal protein
What happens when organisms die (to produces) and what is this process called?
When organisms die , their produces are converted to ammonia by bacterial decomposition
What do nitrifying bacteria in the soil do?
Nitrifying bacteria in the soil then convert ammonia (NH3) into nitrites (NO2 2-) then into nitrates (NO3-)
What can nitrates be absorbed by and what does this do?
Nitrates can be absorbed by other plants to continue the cycle
What do denitrifying bacteria do?
convert soil nitrates into N2 gas.
When denitrifying bacteria convert soil nitrates into N2 gas what is this and when does it happen?
This is a loss of N2 from the cycle which only happens in anaerobic conditions (when O2 levels are low) - due to flooding or accumulation of sewage
How can nitrate enter the cycle?
Nitrate also enters the cycle through the addition of nitrogen rich fertilisers to the soil - made industrially from nitrogen gas
draw the carbon and nitrogen cycles
.
How can nitrogen in the atmosphere (N2) be converted into nitrate (NO3-)?
Lightning (causes a little nitrate to fall in rain) or nitrogen fixation
What is conservation?
Conservation is the protection and wise management of natural resources and the environment
How can nitrate (NO3-) be converted into nitrogen (N2) in the atmosphere?
Denitrification
What is mixed farming?
Farming system where both arable (crops) and pastoral (livestock) farming is carried out.
What is nitrate (NO3-) absorbed into?
plant protein
What do animals do to help conservation and mixed farming?
Animals provide manure and help to maintain soil fertility and reduce the quantity of artificial fertilisers used
When manure has been added to soil, what does it do?
Increases nutrients and soil water holding capacity and improves soil structure
What technique helps to replenish soil nutrients?
If rotations of various crops and forage legumes are used, they replenish soil nutrients
What is another benefit to manure to soil?
Reduce soil erosion
What does recycling wastes do?
Recycling wastes prevents nutrient losses
What is pollution?
Pollution is any human addition (contamination) to a habitat or the environment that leaves it less able to sustain life.
What is pollution the most?
It is the most harmful human impact and affects air, fresh water, sea, soil and land
What are pollutants?
Chemicals of human origin that harm the environment are called pollutants
What is plant protein changed into?
Animal protein (through consumption) or Ammonia (NH3) (through decomposition)
What is animal protein changed into?
Urea (through excretion) or Ammonia (NH3) (through decomposition)
What is urea changed into?
Ammonia (NH3)
What is Ammonia (NH3) changed into and how?
Nitrite (NO2-) through nitrification
What is nitrite (NO2-) changed into and how?
Nitrate (NO3-) through nitrification
What is eutrophication?
A condition where lakes become over-enriched with nutrients, resulting from excess artificial fertilisers washed into rivers and lakes. (Algal bloom then takes place)
What does algal bloom do?
If there is a rapid increase in the growth of alga (algal bloom) as they use up the nutrients
What happens when all the nutrients are used up by algal bloom?
When all the nutrients are used up the algae die and are broken down by bacteria, which use up the oxygen in the water resulting in the death of aquatic organisms such as fish.
What is the agricultural pollutant and control measures?
Pollutant: Slurry and fertiliser
Control measures: Avoid spreading these: - on wet, waterlogged, frozen or steeply sloping land.
- Within 1.5m of any watercourse.
What is the industrial pollutant and control measures?
Pollutant: Sulphur dioxide
Control measures: Fit catalytic scrubbers in factory chimneys
What is the domestic pollutant and control measures?
Pollutant: Plastic bags
Control measures: Bag tax/levy. Reuse/recycle bags.
What is waste management?
Waste management is the collection, transport, processing, recycling or disposal of waste materials, produced by human activity, in an effort to reduce their effect on human health or local aesthetics or amenity.
What does urban rubbish consist of?
Mostly dust, dirt, hair, paper, food scraps, metal, glass and plastic.
what is done with urban rubbish?
Traditional disposal has been used to bury rubbish in landfill sites or incinerate
What does waste management also try to do?
It also tries to reduce waste materials’ effect on the natural world and the environment and to recover resources from them.
Agriculture solution - spreading fertiliser
Spreading the slurry on the land as a fertiliser. This must be managed accurately in order to maximise the value of the nutrients for crop production and minimise their impact on the environment.
Agriculture solution - soil nutrient programmes
Soil nutrient programmes aim to ensure optimum crop yields and protect the quality of water resources by avoiding pollution from agriculture.
Amounts of fertiliser can be controlled so that…
The amounts of fertiliser applied can be determined to ensure optimum yields without causing environmental damage.
What must be known before devising a fertiliser programme?
When devising a fertiliser programme the soil fertility status must be known on foot of regular soil testing.
What must there be recognition of before devising a fertiliser programme?
There must be full recognition of all sources of nutrients, both organic and inorganic
What is important to help maintain a balance of nutrients in the soil?
Regular soil testing is very important to help maintain a balance of nutrients in the soil
