biodiversity Flashcards
1
Q
What is biodiversity?
A
The variety of living organisms
present in an area
2
Q
What is the importance of biodiversity?
A
Essential in maintaining a balanced ecosystem for all organisms • All species are interconnected • In regions of reduced biodiversity, these connections may not be present, which eventually harms all the species in the ecosystem
3
Q
Describe global variations in biodiversity
A
• Tropical, moist regions (that are warm all year round) have the most biodiversity • The UK’s temperate climate (warm summers and cold winters) has less biodiversity • Very cold areas e.g. the Arctic, or very dry areas e.g. deserts, have the least biodiversity • The closer a region is to the equator, the greater the biodiversity
4
Q
What role does measuring biodiversity play in
conservation?
A
• Informs scientists of the species that are present, providing a baseline for the level of biodiversity in an area • From this information, the effects of any changes to an environment can be measured • e.g. the effect of: human activity, disease, climate change etc.
5
Q
What is an Environmental Impact Assessment (EIA)?
A
An assessment done before a major project is undertaken e.g. building a new road, or creating a new nature reserve • The assessment attempts to predict the positive and negative effects of a project on the biodiversity of that area
6
Q
What are the levels that biodiversity can be studied at?
A
- Habitat biodiversity
- Species biodiversity
- Genetic biodiversity
7
Q
What is habitat biodiversity?
A
The number of different habitats found within an area • Each habitat can support a number of different species, therefore in general, the greater the habitat biodiversity, the greater the species diversity will be in that area
8
Q
Give examples of habitat
biodiversity on a large and
small scale
A
Large • The UK is home to many habitat types e.g. meadow, woodland, streams, sand dunes, so it has a large habitat biodiversity • Antarctica is covered by an ice sheet, so has very low habitat biodiversity and very few species live here Small • A countryside that is habitat rich e.g. river, woodland, hedgerows, wild grassland, will be more species rich than a farmed countryside with large ploughed fields making up a single uniform habitat
9
Q
What us a community?
A
All the populations of living
organisms in a particular habitat
10
Q
What is species biodiversity?
A
Made up of two different components: • Species richness - the number of different species living in a particular area • Species evenness - a comparison of the number of individuals of each species living in a community
11
Q
How can an area differ in species biodiversity even if it
has the same number of species?
A
e.g. A cornfield and a grass meadow may both contain 20 species • In the cornfield, corn will make up 95% of the community, with the remaining 5% being weed plants, insects, mice and birds etc • In the grass meadow, the species will be more balanced in their populations
12
Q
What is genetic biodiversity?
A
The variety of genes that make up a species • Many genes are the same for all individuals within a species, however for many genes, alleles exist • This leads to genetic biodiversity within a species • Greater genetic biodiversity within a species allows for better adaptation to a changing environment, and is more likely to result in individuals who are resistant to disease
13
Q
What is sampling?
A
Taking measurements of a limited
number of individual organisms
present in particular area
14
Q
What can sampling be used
for?
A
To estimate the number of organisms in an area without having to count them all • Abundance - the number of individuals of a species present in an area To measure a particular characteristic of an organism • e.g. if you measure the height of a number of plants then calculate an average, your result is likely to be close to the average height of the whole crop You can use the results of a sample to make generalisations or estimates about the number of organisms, distribution of species or measured characteristic throughout the entire habitat
15
Q
What is random sampling?
A
Sampling where each individual in the population has an equal likelihood of selection e.g. to take a random sample at a grass verge: 1. Mark out a grid on the grass using two tape measures laid out at right angles 2. Use random numbers to deter the x-coordinate and the ycoordinate on your grid 3. Take a sample of each of the coordinate pairs generated
16
Q
What is non-random sampling?
A
An alternative sampling method to random sampling, where there sample is not chosen at random. It can be opportunistic, stratified or systematic
17
Q
What is opportunistic sampling?
A
• Uses organisms that are conveniently available • Weakest form of sampling as it may not be representative of the whole population
18
Q
What is stratified sampling?
A
• Some populations can be divided into a number of strata based on a particular characteristic • e.g. the population may be separated into males and females • A random sample is then taken from each of these strata proportional to its size
19
Q
What is systemic sampling?
A
• Different areas within an overall habitat are identified, which are then sampled separately • e.g. may be used to study how plant species change as you move inland from the sea • Often carried out using a line or a belt transect
20
Q
What is a line transect?
A
Involves marking a line along the ground between two poles and taking samples at specie points • This can include describing all the organisms which touch the line, or distances of samples from the line
21
Q
What is a belt transect?
A
Two parallel lines are marked, and samples are taken of the area between the two lines • Provides more information than a line transect
22
Q
Why is a sample never entirely representative of the
organisms present in a habitat?
A
Sampling bias • Selection process may be biased • e.g. you may choose to sample a particular area that has more flowers because it looks interesting • The effects can be reduce by using random sampling, where human involvement in choosing the samples is removed Chance • The organisms selected may, by chance, not be representative of the whole population • Can’t be completely removed from the process, but its effect can be minimised by using a large sample size • More individuals studied, the lower the probability that chance will affect the result; larger the sample size, more reliable the result
23
Q
Describe methods for sampling
animals
A
• A pooter is used to catch small insects • Sweep nets are used to catch insects in areas of long grass • Pitfall traps are used to catch small, crawling invertebrates e.g. beetles, spiders and slugs • Tree beating issued to take samples of invertebrates living in a tree or bush • Kick sampling is used to study the organisms living in a river
24
Q
How are plants normally sampled?
A
Using a quadrat, which can also be used to pinpoint an area in which the sample of plants should be collected • Quadrats can also be used to sample slow-moving animals e.g. limpets, barnacles, mussels and sea anemones
25
Q
Describe the two main types of quadrat
A
Point quadrat • Consists of a frame containing a horizontal bar • At set intervals along the bar, long pins can be pushed through the bar to reach the ground • Each species of plant the pin touches is recorded Frame quadrat • Consists of a square frame divided into a rid of equal sections • The type and number of species within each section of the quadrat is recorded
26
Q
How should quadrats be used?
A
• To collect the most valid representative sample of an area, a random sampling technique should be used • To study how the presence and distribution of organisms across an area of land varies, the quadrants can be place systematically along a line or belt transect
27
Q
How is species richness measured?
A
A list should be compiled of each
species identified. The total number
of species can then be calculated
28
Q
What are identification keys?
A
Images to identify the organism, or a series of questions which classify an organism into a particular species based on the presence of a number of identifiable characteristics • Enable scientists to accurately identify organisms
