Biodiversity Flashcards
(21 cards)
biodiversity can be thought of as…
the variation that exists within and between all forms of life
biodiversity is very important for…
the resilience of ecosystems, in that it allows them to resist changes in the environment
habitat diversity
is the range of different ecosystems or habitats within a particular area or region
species diversity
the mix of different species that exist within a particular area or region can be measured to indicate levels of biodiversity - it can be measured in different ways: species richness and species diversity
species richness
is the number of species within a community
species diversity
looks at the number of different species in a community, and also the evenness of abundance across the different species present
ecosystems with…. are usually…
ecosystems with high species diversity are usually more stable than those with lower species diversity as they are more resilient to environmental changes
a community
is a group of populations of different species living in the same place at the same time that interact with each other
species richness is the simplest way to…
measure species diversity
species richness can be a misleading indicator…
species richness can be a misleading indicator of diversity as it does not take into account the number of individuals of each species
index of diversity
is a measurement that describes the relationship between the numbers of species present and how each species contributes to the total number of organisms that are present in the community
the index of diversity formula:
d= N(N-1) / Σn(n-1)
n= total no. of organisms for a single species in the community
N= total no. of organisms in the community
Σ= sum of
- the larger the number obtained, the higher the level of diversity
Improving grazing land:
-nutritious fast-growing grass is essential for raising healthy livestock
-a mixture of ryegrass and white clover species provides the highest quality grazing pasture, this species only grow on drained fertilised land
-farmers deliberately fertilise and drain the land and sow seeds if these two plant species
-as a result, other plant species are either outcompeted or the changes to the land mean it’s no longer a suitable habitat for them - there is low species richness
-natural grazing land that hasn’t been interfered with has a large variety of plant species present which can support a much greater range and number of insect species and bird species
-wet grasslands have declined steeply in the last 100 years and are now regarded as biodiversity hotspots
sowing of cereal crops:
-for farmland bird species the ploughing of fields and the harvesting of crops and the two points in the year when food is plentiful
-traditionally crops were sowed in the spring
-modern farming has switched to sowing crops in the autumn
-the smaller gap between harvesting and ploughing means there is a very short period of time during the year when food is plentiful for birds however there is less time where the soil is redundant for the farmer
-scientists believe that this switch from autumn to spring sowing will greatly reduce the diversity of farmland birds in the future
organic farming:
-many people favour the produce from organic farms as the food produced is free from harmful chemicals
-the reduction in the use of these chemicals is also thought to benefit biodiversity in and around organic farms
-there are mixed viewpoints and scientific evidence on these claims however, but this is a good example to show the balance between conservation efforts within effective large-scale farming practices
the decline of the bumblebee:
-bumblebee are essential pollinators that pollinate wildflowers and valued crops such as oilseed rape and peas
-almost a quarter of the European bumblebee species are threatened with extinction
-there has been a very rapid decline in bumblebee numbers in recent years
-bumblebees require habitats with a large number of flowering plants to ensure a supply of pollen and nectar all year round, examples of this are hedgerows, field margins and grasslands
-it has been suggested that the extensive farming of crops and the use of pesticides are contributing to this decline
-there is still inconclusive evidence as to weather these modern farming methods are the cause of the bee’s falling numbers
what are two factors that make farming economically viable
-a high yield
-a high profit
genetic diversity within, or between species, can be made by comparing:
-the frequency of measurable or observable characteristics
-the base sequence of DNA
-the base sequence of mRNA
-the amino acid proteins encoded by DNA and mRNA
two types of sampling:
random
systematic
random sampling
due to chance, no bias
systematic sampling
points are chosen
