Ecology Flashcards
what does every food chain start with
a producer, mostly plants, sometimes algae
why are producers important in food chains
because they synthesise complex molecules
- they are the source of all biomass in a community
what is biomass
complex molecules such as glucose
what happens to biomass
it passes down the food chain to other organisms
what are primary consumers
organisms that eat producers
what is the secondary consumers
the animal that eats a primary consumer
what is a tertiary consumer
the animal that eats a secondary consumer
what are predators
consumers that kill and eat other animals
what are prey
the animal that is eaten
what happens if you increase the number of prey in one area
- prey population increases
- predators have more prey to kill and eat
- more prey will be eaten and population of prey falls
- predator have less prey to kill and eat, so population of predators fall
- because predator population has fallen, more prey can survive and reproduce
what is random sampling used to do
to compare the numbers of organisms in different areas
how to do random sampling
- using a quadrat, place it on the ground then count the number of organisms inside the quadrat
what types of organisms can random sampling be used for
plants or slow moving animals
how to carry out random sampling
- quadrats placed at random locations across the area
- one way to do this is to use random numbers to select different locations
- count the number of each organism in the quadrat
- keep doing this until awe have sampled a large number of random locations
why is it important that we place the quadrat a large number of times
to make valid results more likely. if we placed the quadrat once, it wouldnt give us a sample that represents the whole area
total population size equation
total population size = (total area/ area sampled) x number of organisms of that species counted in that sample
how to carry out sampling along a transect
- Place the transect so it runs across the habitat we are looking at
- Place the first quadrat at the start of the transect
- Count the different plants in the quadrat
- Move the quadrat closer inland by a set distance
- keep doing his u til you move further inland
- move the tape along and repeat the whole process
what is a transect
a line such as a tape measure or a piece of rope
when would we use sampling along a transect
to see how the numbers of organisms change across a habitat
sampling organisms practical method
- Start by estimating the total population of daisies in a field using RANDOM SAMPLING
- Place two tape measures at right angles (they should be 20m in length)
- Get two bags filled with numbers from 1 to 20
- (students work in groups of 3) have one student remove a number and whatever number they get, they move to that point on the tape measure, repeat this w another students
- Get the third student to place the quadrat where the other students numbers meet
- record the number of daisies in the first quadrat
- Repeat this process 9 more times for a total of 10 samples
how to improve accuracy of results
increase the number of quadrat throws to cover a larger percentage of an area
how to measure the effect of a factor on the distribution of species
- use a transect line
- Record the number of daises at the start of the transect and record the light intensity
- move the quadrat 1m down tape measure and repeat the measurements, do this all the way down the tape measure
how does the carbon cycle start
with co2 in the atmosphere
how does carbon taken into the carbon cycle
by photosynthesis