!! 4.7.2 Flashcards
what are predators
consumers that kill or eat other animals
why does the number of prey fluxuate
based on their surroundings
e.g in a milder winter there’s more food so more survive
what happens to the number of prey and predators in a stable community
the number of both falls and rises
which organisms are the producers of biomass for life on earth
photosynthetic organisms
what do all food chains begin with
and a real life example
a producer which synthesises molecules
usually a plant or algae which makes glucose by photosynthesis
what can be represented by food chains
feeding relationships in communities
what is a community
every individual from every species in a habitat
what is the most significant effect on biodiversity from human population increase
reduction in habitat
3 ways humans reduced habitat effecting biodiversity
buildings
farming
dumping waste
how have buildings effected biodiversity on earth
growing population needs somewhere to live
quarrying for building materials massively increased
leading to habitat destruction
how has farming effected biodiversity on earth
more and more land devoted to farming
e,g more and more deforestation of the rainforest for cattle ranches for burgers
how has the growing human population dumping waste affected Earth’s biodiversity
more and more consumption leads to more and more landfill
increase of human population effect on raw materials
raw materials being used up rapidly such as coal, oil and wood
which 3 places can pollution occur
water
air
land
how does pollution occur in water
fertiliser, runs off farms into river and streams
sewage, pumped into rivers and streams
toxic chemicals
how does pollution occur on land
landfill
pesticides
herbicides
toxic chemicals
may all be washed into water
how does pollution occur in the air
give an example
smoke
acidic gases
e.g sulfur dioxide dissolves in rain, forms sulfuric acid and then becomes acid rain
how does climate change have an impact on biodiversity
changing distribution - organisms moving to different parts of the world
plants blooming earlier
why may removing one species from an ecosystem make it unstable
interdependence between different species
one species may rely on another species for services such as food, shelter, pollination, and seed dispersal.
removing one species from an ecosystem could remove a key predator or prey.
either increasing or reducing population size
what is a transect
a line defined using a tape measure
where are transects usually placed
across a changing habitat
e.g across a rocky shore
basic transect method
use tape measure to produce transect across (where you’re measuring)
place quadrats along transect at appropriate intervals
measure presence of each species and how many of each there are
repeat 10 times
what can transects be used to investigate
the effect of a factor on the distribution of a species
what is a quadrat
a square frame that can be used to estimate population size
calulation for estimated population size using qaudrats
no. individuals counted × area sampled / total survey area
