Biodiversity essential notes Flashcards
State the types of biodiversity
- Habitat biodiversity 2. Species biodiversity 3. Genetic biodiversity
Discuss what habitat biodiversity means
- Habitat diversity refers to the number of environments on in which life exists
- Each habitat contains the organisms adapted to survive there
- The greater the habitat diversity, the greater the biodiversity overall
- Sand dunes, woodland, meadows and streams are examples of different environmental conditions, allowing the survival of differently adapted organisms
- Maintaining different habitats allows the great diversity in the types of species we have to be maintained
Discuss what species biodiversity means
- Species diversity refers to the variety of organisms in a habitat
- It is made up of species richness and species evenness
- Species richness refers to the number of different species in a habitat
- Species evenness compares the proportions of the community made up by the different species
- Having high species diversity maintains functioning ecosystems, and provides us with sustainable and valuable resources
Discuss what genetic biodiversity means
- Genetic diversity is a measure of the variety that exists within the species
- It is measured by the number of genes present in the species (including all the different alleles)
- Having high genetic variation in a species increases the chances of the species adapting to environmental changes (less likely to become extinct)
Explain why sampling is necessary
- It is important to quantify biodiversity to measure the possible impact of development, or conservation efforts
- But counting every organism in a large area is impractical
- Smaller areas of a habitat are therefore sampled
- In a way that is representative
- The data are used to make an estimate for the larger area
Describe the principles of random sampling
- Random sampling means the investigator does not select which areas or individuals will be sampled
- This is a way that samples are made more representative and avoid bias
- Random sampling is used when a two-dimensional area is being sampled, for example, with quadrats
Describe the types of non-random sampling
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Describe how sampling can be made more reliable and representative
- Removing as much bias as possible. For example, using random or systematic sampling
- Accounting for daily and seasonal changes
- Reducing the element of chance, by taking large sample sizes or repeat measurements
Describe how you would use quadrats to estimate plant biodiversity in an area
- Used to measure the biodiversity in a two-dimensional area
- Often to compare and find the difference between two areas
- Choose an area and decide on a representative number of samples
- Arrange tape measures like x-y axes of a grid
- Use a calculator to generate random numbers as coordinates
- Place quadrats at determined coordinates and
- Record species richness by identifying species present using an identification key
- Record abundance of each species by estimation
- Use species richness and evenness to determine biodiversity
- Analysed with a t-test
Describe how you would use transects to investigate plant biodiversity
- Used to investigate the effect of a changing factor (such soil pH, moisture) over a particular linear distance
- Decide on the distance for the transect
- Place quadrat or point frame at regular intervals (systematic sampling) along the transect
- For each quadrat record:
- The factor being investigated
- Any control variables
- Species present using identification key
- and estimate species abundance
- Biodiversity at at each point in the transect can be calculated
- Parallel transects can be used to repeat the investigation
- Analysed with a Spearman rank correlation test
Describe the ways in which plant abundance can be measured
- Measuring actual density: if the individual plants are easy to count, record the number per the area of the quadrat
- Percentage cover (frequency): using the number of grid squares the plant is present in to estimate a percentage
- In a point frame, each species that touching each of the pins is recorded
Describe the techniques that are appropriate for measuring animal abundance
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Describe how estimates of animal abundances can be made from sample collection
- Large insects and small mammals that have been captured
- Are marked (in a way that doesn’t cause harm) (C1)
- They are then released, and traps are set again.
- Some individuals are trapped again (C2)
- The numbers of marked individuals captured again (C3), is used to estimate the total wild population
- Using the equation Total population = (C1 x C2)/C3
Describe how species richness and evenness can be used to determine the biodiversity of an area
![](https://s3.amazonaws.com/brainscape-prod/system/cm/417/662/772/a_image_thumb.png?1601305319)
Describe the significance of a low Biodiversity index
- Few successful (dominant) species in the ecosystem
- Stressful or extreme environmental conditions, few niches
- Few species make up the ecosystem, but with very specific adaptations
- Simple food webs (look more like food chains)
- Changes to the environment (human impact, climate change, new disease or predator) have a big impact on the ecosystem and could result in population eradication
Describe the significance of a high Biodiversity index
- High number of species in the ecosystem have large population (no single dominating species)
- Less extreme conditions, more available niches for species to survive
- Many species successful in the habitat, with fewer specific adaptations required
- Complex food webs exist (each species has food options)
- Ecosystems are more resilient to changes in the environment (human impact, climate change, new disease or predator)