4- ecology and the environment Flashcards
population
a group of organisms of the same species living in the same place at the same time
community
all of the populations living in the same area at the same time
habitat
where an organism lives
ecosystem
all the biotic factors and all the abiotic factors that interact within an area at one time
quadrats
Quadrats are square frames made of wood or wire
They can be a variety of sizes eg. 0.25m2 or 1m2
They are placed on the ground and the organisms within them are recorded
Plants species are commonly studied using quadrats to estimate the abundance
quadrats can be used to measure abundance by recording
The number of an individual species: the total number of individuals of a single species (eg. buttercups) is recorded
Species richness: the total number of different species (but not the number of individuals of each species) is recorded
Percentage cover: the approximate percentage of the quadrat area in which an individual species is found is recorded (this method is used when it is difficult to count individuals of the plant species being recorded eg. grass or moss
apparatus needed to investigate population size in 2 different areas using quadrats
2 tape measures
Quadrat
Random number generator
Species key
method to investigate population in size in 2 different areas using quadrats
1) take a tape measure to lay out in a survey area in the chosen habitat
2) use a random number generator and create a list of coordinates to place your first quadrant
3) count the number of your chosen plant species that are found within this quadrat
4) estimate the population of dandelions in your survey areas using this equation: (total area/ area sampled) x total number of plants counted
results of investigating population in size in 2 different areas using quadrats
Once the results have been collected and the averages calculated, we can compare the abundance of the study species in each survey area
Species abundance is likely to be influenced by biotic factors such as:
Competition
Predator-prey relationships
Interactions with other organisms within the food chain or food web
The abundance will also be influenced by abiotic factors such as:
Light intensity
Mineral availability
Water availability
pH
Temperature
Salinity
limitations to investigating population in size in 2 different areas using quadrats
It can be easy to miss individual organisms when counting in a quadrat, especially if they are covered by a different species
Solution: Use a pencil or stick to carefully move leaves out of the way to check if there is anything else underneath
Identifying species may be tricky
Solution: Use a species key to identify the species
corms to investigate population in size in 2 different areas using quadrats
C - We are changing the study area where we are collecting the data
O - We will count the same species of organism in each quadrat
R - We will repeat the investigation several times to ensure reliability
M - We will count the number of the designated study species found across all quadrats
S - We will control the size of the quadrat, the random way that quadrats are placed on the ground, the day that the results were collected
abiotic
non living
biotic
living
an abiotic factor is
a non living factor within an environment such as temperature, light intensity and wind speed
light intensity affect on community
LIGHT IS NEEDED BY PLANTS FOR
PHOTOSYNTHESIS. MORE LIGHT LEADS TO
AN INCREASE IN RATE OF PHOTOSYNTHESIS
AND AN INCREASE IN PLANT GROWTH RATE
temperature affect on community
AFFECTS THE RATE OF PHOTOSYNTHESIS
IN PLANTS
moisture levels affect own community
PLANTS AND ANIMALS REQUIRE WATER
TO SURVIVE
soil pH and mineral content affect on community
DIFFERENT SPECIES OF PLANTS ARE
ADAPTED TO DIFFERENT SOIL pH LEVELS
AND NUTRIENT CONCENTRATION LEVELS
wind intensity and direction affect on community
WIND SPEED AFFECTS TRANSPIRATION RATE IN PLANTS. TRANSPIRATION AFFECTS THE RATE OF PHOTOSYNTHESIS AS IT ENSURES WATER AND MINERAL IONS ARE TRANSPORTED TO THE LEAVES
carbon dioxide levels for plants affect on community
CO, IS REQUIRED FOR PHOTOSYNTHESIS IN
PLANTS. CO CONCENTRATION AFFECTS
THE RATE OF PHOTOSYNTHESIS
oxygen levels for aquatic animals affect on community
SOME AQUATIC ANIMALS (SUCH AS FISH)
CAN ONLY SURVIVE IN WATER WITH HIGH
OXYGEN CONCENTRATIONS
availability of food affect on community
MORE FOOD MEANS ORGANISMS HAVE A HIGHER CHANCE OF SURVIVING AND REPRODUCING. THIS MEANS THEIR POPULATIONS CAN INCREASE
new predators affect on community
IN BALANCED ECOSYSTEMS, PREDATORS CATCH ENOUGH PREY TO SURVIVE BUT NOT SO MANY THAT THEY WIPE OUT THE PREY POPULATION. IF A NEW PREDATOR ISI NTRODUCED TO THE ECOSYSTEM. IT MAY BECOME UNBALANCED
new pathogens affect on community
if a new pathogen enters an ecosystem the populations living there will have no immunity or resistance to it and the population may decline or be wiped out
competition affect on community
IF TWO SPECIES COMPETE FOR THE SAME RESOURCE(S) AND ONE IS BETTER ADAPTED TO TAKE ADVANTAGE OF THESE RESOURCES, THEN THAT SPECIES WILL OUTCOMPETE THE OTHER. THIS MAY CONTINUE UNTIL THERE ARE TOO FEW MEMBERS OF THE LESSER ADAPTED SPECIES TO BREED SUCCESSFULLY
trophic levels are used to
describe the feeding relationships between organisms
producers
produce their own organic nutrients usually using energy from sunlight
primary consumers
herbivores- feed on producers
secondary consumers
predators that feed on primary consumers
tertiary consumers
predators that feed on secondary consumers
food chain-
Producer: food chains always begin with a producer
Primary consumer: producers are eaten by primary consumers (herbivores/omnivores)
Secondary consumer: primary consumers are eaten by secondary consumers (carnivores/omnivores)
Tertiary consumer: secondary consumers are eaten by tertiary consumers (carnivores/omnivores)
a food chain shows
the transfer of energy from one organism to the next
the source of all energy in a food chain is
light energy from the sun
the arrows on a food chain show
the transfer of energy from one trophic level of the food chain to the next
in order for energy to be passed on it has to be
consumed
a food web is
a network of interconnected food chains
food webs show
interdependance- how the change in one population can affect others within the food web
a food pyramid of numbers shows
how many organisms we are talking about at each level of a food chain
the width of a food pyramid indicates
the number of organisms at that trophic level
a pyramid of biomass shows
how much mass the creatures at each level would have without including all the water that is in the organism
how much energy of each trophic level is actually transferred
10%
losses of energy are due to
Organisms rarely eat every part of the organism they are consuming – some of the biological material of plants and animals may be inedible (eg. many predators do not consume the bones of their prey)
Not all the ingested material is digested and absorbed, some is egested as faeces
Energy is used for movement
Energy is used to generate heat
Energy is used for metabolic processes
Some absorbed material is lost as waste:
Carbon dioxide and water are waste products of respiration
Water and urea are the waste products in the urine, which is produced when proteins are broken down
describe the carbon cycle
Carbon is taken out of the atmosphere in the form of carbon dioxide by plants to be used for photosynthesis
It is passed on to animals (and microorganisms) by feeding
It is returned to the atmosphere in the form of carbon dioxide by plants, animals and microorganisms as a result of respiration
If animals and plants die in conditions where decomposing microorganisms are not present the carbon in their bodies can be converted, over millions of years and significant pressure, into fossil fuels
When fossil fuels are burned (the process is known as combustion), the carbon combines with oxygen and carbon dioxide is released into the atmosphere
Increased use of fossil fuels is contributing to an increase in the carbon dioxide content of the atmosphere
In addition, mass deforestation is reducing the amount of producers available to take carbon dioxide out of the atmosphere by photosynthesis
This problem is exacerbated by the fact that in many areas of the world, deforestation is taking place for land rather than for the trees themselves, and as such they are burnt down, releasing yet more carbon dioxide into the atmosphere
biological consequences of sulphur dioxides and nitrogen oxides
Combustion of fossil fuels that contain sulphur impurities creates sulphur dioxide. Nitrogen oxides are also produced during fossil fuel combustion. These gases react with oxygen and dissolve in rainwater to produce dilute sulphuric acid and nitric acid, which leads to acid rain.
greenhouse gases
Water vapour Carbon dioxide Methane Nitrous oxides CFCs
human activities that contribute to increasing levels of carbon dioxide and methane
Carbon dioxide is produced during the combustion of fossil fuel
Methane is produced by cattle as they digest grass and released by rice paddy fields
the greenhouse affect
The Sun emits rays that enter the Earth’s atmosphere
The heat bounces back from the Earth’s surface
Some heat is reflected back out into space
Some heat is absorbed by greenhouse gases and is trapped within the Earth’s atmosphere – this is normal
However, as the levels of greenhouse gases in the atmosphere rise due to human activities the Earth’s average temperature rises beyond normal (an enhanced greenhouse effect), causing global warming
consequences of global warming
Ocean temperatures increasing, causing melting of polar ice caps / rising sea levels / flooding / coral bleaching
Increasing temperatures causing extreme weather like super storms, flooding, droughts
Changes in or loss of habitats due to these extreme weather events
Decreases in biodiversity as food chains are disrupted and extinction rates increase
Increases in migration of species to new places, including increased spread of pests and disease
