UNIT 3 Flashcards
population
number of organsims of one species in an area
producer
green plant that makes its own food using light energy by photosynthesis
consumer
eats other organsims to obtain energy
herbivore
only eats plant material
carnivore
only eats animal material
omnivore
eats both plant and animal material
predator
hunts another organsim for food
prey
organism that is hunted for food
what is a food chain
a diagram that shows the feeding relationship between organisms in an ecosystem
what do the arrows in a food chain represent
the energy flow
when does competition occur in an ecosystem
when 2 or more members of a community need the same resources which is in short supply
interspecific
competition between member of different species for one or a few resources
intraspecific
competition between members of the same species for all of their resources
what type of competition is the most intense and why
intraspecific
they need the same resources
what is a niche
the role it plays within its community
how do organisms lose energy
heat
movement
undigested materials
what happens as you go along the food chain
the number of organisms die so does the the total of energy
what does a pyramid do
shows the number of organisms at each stage of the food chain
what is biodiversity
the total variation that exists amongst all living things
species
group of organisms that can interbreed to produce fertile offspring
ecosystem
an ecosystem contains all the organisms that live in an area living alongside the non living components
name some biotic factors
food avalibility
predators
disease
competion
grazing
name some abiotic factors
temperature
ph
moisture
light intensity
how do u measure soil ph and prevent errors
measure with a ph metre and wipe the probe down before next use
how do u measure light intensity
measure with a light metre and dont cast a shadow
how do u measure the moistute
measure using a moisture meter and the wipe the probe before next use
how do u measure temprature
use a thermometer and leave for a bit
what do we use for sampling
quadrats and pitfall traps
what are some of the errors and how du u fix them ( pitfalls )
trap not level with soil - make sure is level
leaving pitfall trap for too long - check trap regularly
failure to camouflage - cover with a leaf
what is the error that can happen with quadrats and how to fix it
Numbers and types of organisms are not representative of the ecosystem - throw quadrat at random and also many times
what is the first stage of photo synthesis
light reactions
what happens in the first stage of photosynthesis
light energy from the sun is trapped by chlorophyll in the chloroplasts
This light energy is converted into chemical energy in the form of ATP
Water is split using energy to produce hydrogen and oxygen
oxygen diffuses from the cell - this is a by product
hydrogen and ATP are taken to the next stage , carbon fixation
what is the second stage of photosynthesis
carbon fixation
what happens during stage 2 of photosynthesis
uses hydrogen and ATP
the energy from ATP is used to combine the hydrogen and carbon dioxide to produce sugar
what is type of reaction is carbon fixation
enzyme controlled
what are the ways sugar can be used after being produced in carbon fixation
broken down during respiration to produce energy
converted into starch and stored away as an energy store
converted into cellulose which cell walls are made from
what is a limiting factor
a factor that limits how fast a reaction can go if it is in short supply
what are the 3 enviromental factors that affect the rate of photosynthesis and therefore plant growth?
light intensity
carbon dioxide concentration
temprature
an increased human population requires…..
an increased food yield
how can a farmer increase the food yield of crops
with fertilisers and pesticides
what are some of the issues with farmers using feritlisers
fertlisers can leach into freshwater adding extra unwanted nutrients
fertilisers greatly increase the growth of algae in the water causing algae blooms
algae blooms block light getting through killing aquatic plants and essentially aquatic animals
this is food for bacteria which greatly increase in numbers
the bacteria use up lots of oxygen killing aquatic life
what are some problems with farmers using pesticides
unintended effects on other populations
the pesticides can be passed on to another organism passing them along the foodchain
what are some alternatives to pesticides to increase crop yield
biological controls
GM crops
indictor species
what is a biological control
introducing a natural predator to the growjng crop area to decrease the population of the pest
what are GM crops
genetically modified crops that grow quicker and last longer
what is and indicator species
species that by there presence or absence indicate environmental quality/levels of pollution
how is new variation created in genetic material
Errors in genetic material arise through a process called mutation
why variation needed with in a population
so they can adapt in response to changing enviromental conditions.
what is mutation
a random change to the genetic material of an organism
mutations are….
spontaneous
what can cause mutation to speed up
radiation
some chemicals
what is natural selection
the process that drives evolution
what is the process of natural selection
a variation between members of a species starts
natural selection occurs when there are selection pressures
best adapted individuals survive
what is a species
a group of organisms that can reproduce to make a fertile offspring
what is the process of speciation
isolation- isolated by isolating barriers
mutations - different mutations appear creating variation
natural selection - selection pressures are different the most adapted survive
speciation - the populations have evolved into different species
