4.2.1 - Biodiversity Flashcards
Define biodiversity
The variety of living organisms in a present area
What does biodiversity include ?
Plants, animals, fungi and other living things
How is biodiversity essential ?
It is essential in maintaining a balanced ecosystem for all organisms
Why do we rely on balanced ecosystems ?
They provide us with the food, oxygen and other materials we need to survive
Which regions have the most biodiversity ?
Tropical mois regions
Which regions have the least biodiversity ?
- Very cold areas such as the arctic
- Very dry areas such as deserts
How are the equator and biodiversity linked ?
As you get closer to the equator the more biodiversity there is
Why does measuring biodiversity play an important role ?
- It informs scientists of the species that are present, thus providing a baseline for the level of biodiversity in an area
- The effect of any changes to an environment can be measured
What are the three levels of biodiversity ?
- Habitat
- Species
- Genetic
What is habitat biodiversity?
The number of different habitats
What is the correlation between habitat biodiversity and species biodiversity ?
In general, the greater the habitat biodiversity, the greater the species biodiversity will be within that area
What is species biodiversity?
The number of species and the abundance of each species in a particular location
What is species richness ?
The number of different species living in an area
What is species evenness ?
A comparison of the numbers of individuals of each species living in a community
Define community
The community is all the populations of living organisms in a particular habitat
What is genetic biodiversity?
The total number of genetic characteristics in the genetic make-up of a species
What is an allele ?
A different version of a gene
What does an allele lead to ?
It can lead to genetic biodiversity within a species
What does greater genetic biodiversity allow ?
- Better adaptation to a changing environment
- More likely to result in individuals who are resistant to diseases
What is sampling ?
The process of collecting data in a suitable way
Why is sampling important?
- It means data is representative is as it can be
- It makes data collection more manageable
What can sampling be used to estimate ?
The number of organisms in an area without having to count them all
What does abundance refer to ?
The number of individuals of a species present in an area
What can sampling be used to measure ?
- A particular characteristic of an organism
- e.g. height
What is random sampling?
Each individual in the population has an equal likelihood of selection
What is non-random sampling?
An alternative sampling method where the sample is not chosen at random
How could an area be randomly sampled?
- A grid could be laid out using two tape measures
- A random number generator is used to generate a grid reference
- A quadrat is placed at the grid reference
- A sample is collected
What are the 3 main non-random sampling techniques?
- Opportunistic
- Stratified
- Systematic
What is opportunistic sampling?
Sampling which uses organisms conveniently available
What is stratified sampling?
- Some populations can be divided into distinct groups
- A random sample is then taken from each of these groups proportional to its size
What is systematic sampling?
Samples are taken at regular intervals
Why wont a sample be entirely representative ?
- There may be :
- Sampling bias
- Chance
Sampling bias
- The selection process may be biased
- The effects of sampling bias can be reduced using random sampling, where human involvement in choosing the sample is removed
Chance
- The organism selected may not be representative of the whole population
- The greater the number of individuals studied, the lower the probability that chance will influence the result.
- Therefore the larger the sample size, the more reliable the result
What is a frame quadrat?
- A frame quadrat consists of a square frame divided into a grid of equal sections
What is a point quadrat?
- A point quadrat consists of a frame containing a horizontal bar, pins can be pushed down at set intervals to reach the ground.
- The plant which the pin touches is what is recorded
What is a line transect?
A line is marked along the ground between two points and samples are taken at specified points
What is a belt transect?
Two parallel lines are marked and samples are taken of the area between the two lines
What is an interrupted belt transect?
A transect is marked out and frame quadrats are placed at regular intervals along the transect
When would systematic sampling be useful?
When studying how biodiversity changes along an area
When would random sampling be useful?
If the study is only looking at biodiversity in one area
Give 5 methods of sampling animals
- Using pooters
- Sweep nets
- Pitfall trap
- Tree beating
- Kick sampling
What kind of animals are sampled using a pooter?
Small insects
What kind of animals are sampled using sweep nets ?
Insects, particularly those that live in long grassland
What kind of animals are sampled using pitfall traps?
Small crawling invertebrates
What kind of animals are sampled using tree beating?
Invertebrates which live in trees/bushes
What kind of animals are sampled using kick sampling?
Animals which inhabit river beds
Describe how pooters can be used to sample animals
By sucking on a mouthpiece insects are drawn into the holding chamber
Describe how pitfall traps can be used to sample animals
- A hole is dug and insects fall in
- This is left overnight so nocturnal species are also sampled
Why must a pitfall trap have a roof structure?
To prevent the hole filling with rainwater
Describe how tree beating can be used to sample animals
- A large white cloth is stretched out under the tree
- The tree is then shaken/beaten
- Animals fall onto the sheet where they can be collected
Describe how kick sampling can be used to sample animals
- The riverbank and bed are kicked to disturb substrate
- A net is held downstream to capture organisms that have been disturbed
Give the 2 ways plants can be sampled
- Frame quadrats
- Point quadrats
Define biotic factor
The living components of an ecosystem
Give 3 ways frame quadrats can be used to sample plants
Frame quadrats can be used to generate data on:
- density
- % cover
- frequency
Why would a temperature probe linked to a data logger be advantageous over a thermometer?
- Rapid changes can be detected
- Human error in taking reading reduced
- High degree of precision can be achieved
- Data can be stored and tracked on a computer
What are the 2 ways of measuring biodiversity?
- Species richness
- Species evenness
What is species richness?
A measure of the number of different species living in an area
What is species evenness?
How close in number the populations of each species in an environment are
What information is required to determine species richness?
Total number of species present