organism and their environment Flashcards
what are producers
organisms that produce their own organic nutrients usually using energy from sunlight. plants are producers as they carry out photosynthesis to make glucose
what is a herbivore
an animal that gets its energy by consuming/eating plants
what is a carnivore
an animal that gets its energy by consuming/eating other animals
what is a primary consumer
herbivores – they feed on producers (plants)
what is a secondary consumer
predators that feed on primary consumers
what is a tertiary consumer
predators that feed on secondary consumer
what is a decomposer
bacteria and fungi that get their energy from feeding off dead and decaying organisms and undigested waste (such as faeces) by secreting enzymes to break them down
what is a food chain
shows the energy transfer from one organism to the next, starting with a producer
what is the energy source for all food chains
light energy from the sun
what do the arrows in a food chain
The arrows in a food chain show the transfer of energy from one trophic level to the next
example of producers and consumers in a food chain
producer: grass seed, makes its own food using energy from sunlight in photosynthesis
primary consumer: vole, eats the producer
secondary consumer: barn owl, eats the primary consumer
whats a food web
a food web is a network of interconnected food chains
what is interdependence
how the change in one population can affect others within the food webs
what is a trophic level
describes the position of an organism in a food chain, web or pyramid
what do producers convert light energy to
chemical energy
what type of process is energy flow
non-cyclical process – once the energy gets to the top of the food chain
or web, it is not recycled but ‘lost’ to the environment
what trophic level is producer and why
THEY PRODUCE THEIR OWN ORGANIC NUTRIENTS
USUALLY USING ENERGY FROM SUNLIGHT
what tropic level the primary consumers and why
HERBIVORES - THEY FEED ON PRODUCERS (PLANTS)
what trophic level is the secondary consumers and why
PREDATORS THAT FEED ON PRIMARY CONSUMERS
what trophic level is the tertiary consumers and why
PREDATORS THAT FEED ON SECONDARY CONSUMERS
what are scavengers
Scavengers are carnivores that eat the dead remains of animals killed by predators
what are the stages of the carbon cycle
-Carbon enters the atmosphere as CO2.
-CO2 is absorbed by autotrophs such as green plants.
-Animals consume plants, thereby, incorporating carbon into their system. (known as fixation)
-Animals and plants die, their bodies decompose and carbon is reabsorbed back into the atmosphere.
what is the process by which carbon dioxide goes into animals
feeding
how is carbon dioxide returned to the atmosphere
plants, animals and microorganisms as a result of respiration
what are fossil fuels
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.
when fossil fuels are burned what does it do to the environment
When fossil fuels are burned (the process is known as combustion), the carbon combines with oxygen and carbon dioxide is released into the atmosphere
what does mass deforestation lead to
In addition, mass deforestation is reducing the amount of producers available to take carbon dioxide out of the atmosphere by photosynthesis
how are clouds formed
Energy from the Sun heats the Earth’s surface and water evaporates from oceans, rivers and lakes
Transpiration from plants releases water vapour into the air
The moist air cools down as it rises
Water vapour condenses back into liquid water, forming clouds
how does water return back to earth as precipitation
Water returns to Earth in the form of precipitation
As the water droplets in the cloud get bigger and heavier, they begin to fall as rain, snow and sleet
This is called precipitation
what is nitrogen fixing bacteria
found ‘free living’ in soil and also in the root nodules of
certain plants (peas, beans, clover – we call them leguminous plants) take N2 gas
and change it into nitrates in the soil
what do plants do with nitrates
Plants absorb the nitrates they find in the soil and use the nitrogen in them to make proteins
how does nitrogen pass onto animals
Animals eat the plants (or other animals) and get the nitrogen they need from the proteins in the plant or animal
how does nitrogen go back into the soil
Waste from animals sends nitrogen back into the soil as ammonium compounds
what happens when animals decay
they decay and all the proteins inside them are broken
down into ammonium compounds and put back into the soil by decomposers
what is nitrifying bacteria
plants cannot absorb ammonium compounds
nitrifying bacteria found in soil converts ammonium compounds to nitrites and then back to nitrates which can be absorbed by the plants
what is denitrifying bacteria
These bacteria take the nitrates out of the soil and convert them back into N2 gas
definition of population
a group of organisms of one species, living in the same area at the same time
what is the definition of a community?
all of the populations of different species in an ecosystem
what is an ecosystem
a unit containing the community of organisms and their environment, interacting together
what is population growth in organisms controlled by
Food supply
Predation
Disease
in recent times why has the population been growing exponentially
Improved technology leading to an abundance of food = rapid increase in birth rate
what can cause a decrease in death rate
Improved medicine, hygiene and health care = decrease in death rate
4 phases of sigmoid population curve
lag phase
exponential growth phase (log phase)
stationary phase
death phase
what happens in lag phase
organisms are adapting to the environment before they are able
to reproduce; in addition, at this stage there are very few organisms and so reproduction is not producing larger numbers of offspring
what happens in log/exponential phase
food supply is abundant, birth rate is rapid
and death rate is low; growth is exponential and only limited by the number of new individuals that can be produced
what happens in stationary phase
population levels out due to a factor in the environment, such
as a nutrient, becoming limited as it is not being replenished; birth rate and death rate are equal and will remain so until either the nutrient is replenished or becomes severely limited
what happens in death phase
population decreases as death rate is now greater than birth rate;
this is usually because food supply is short or metabolic wastes produced by the population have built up to toxic levels
what are some factors that can prevent a population from looking like a sigmoid curve
- changing temperature or light
- predators
- disease
- immigration (individuals moving into the area)
- emigration (individuals moving out of the area)
removal of carbon dioxide from the atmosphere
photosynthesis
fossilisation
what is fossilisation
the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form. doesnt decompose to release co2
addition of carbon dioxide to the atmosphere
respiration
decomposition
combustion
how does decomposition release co2 in the atmosphere
Decomposition is the process by which organic matter, such as dead plant or animal material, is broken down by microorganisms and other decomposers into simpler compounds like carbon dioxide (CO2), water, and other organic compounds.
During this process, microorganisms consume the organic matter as a source of energy and release CO2 as a byproduct of respiration.
how is nitrogen added to the soil (nitrifying bacteria)
nitrifying bacteria
bacteria living in the soil use ammonia as a source of energy, in the process of getting energy from ammonia called nitrification, bacteria produce nitrates
nitrates are oxidised to nitrates
how is nitrogen added to the soil (nitrogen fixing bacteria)
a special group of nitrifying bacteria that can absorb nitrogen as a gas from the air, these bacteria live in leguminous plants,
how is nitrogen added to the soil (lightning)
high temperature of lightning discharge causes some of the nitrogen and oxygen in the air to combine and form oxides of nitrogen.
These dissolve in the rain and are washed into the soil as weak acids, where they form nitrates.
how is nitrogen removed from the soil
uptake by plants
leaching (Nitrates are soluble and as rainwater passes through the soil it dissolves the nitrates carrying it to deeper layers of the soil)
Denitrifying bacteria (bacteria that get their energy from breaking down nitrates to nitrogen gas)
what is the importance of organisms that feed on decaying and dead animals
prevents accumulation of dead matter
recycles nutrients
releases carbon dioxide
what does pyramid of numbers show
how many organisms are feeding at each trophic level. is not a pyramid shape
what does pyramid of biomass/energy show
shows the amount of energy passed on from one trophic level to the next
always a pyramid shape
bottom layer always producers and is followed by primary consumer, secondary consumer, tertiary consumer etc.
diff between pyramid of biomass and numbers
pyramid of biomass is pyramid shape, pyramid of numbers is not
producers have more bio mass than primary consumers
so one tree provides food for many primary consumers
each secondary consumer eats many primary consumers
what are nitrogen compounds cows eat but not used in the milk used for
deamination
nitrogen-containing component of amino acids converted to ammonia which is toxic so converted to urea and passed out through urine
in field
nitrification, turns nitrogen to nitrate ions
nitrates are taken up by plants
these can run off from fields into lakes causing eutrophication, algal bloom
stages of nitrogen cycle
nitrogen fixation:
nitrogen from the atmosphere moves into the soil, bacteria and sometimes lightning can fix nitrogen
ammonification:
fixed nitrogen is converted to ammonium
nitrification:
bacteria convert ammonium to nitrites which are then oxidised to nitrates
denitrification:
denitrifying bacteria convert nitrate and nitrite ions back to N2 gas
