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Flashcards in Biodiversity Deck (71)
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Define the term “ecosystem".

All interacting living organisms and the non-living (abiotic) conditions in an area.


Define the term “community”.

All the populations of living organisms in a particular habitat.


Define the term “habitat”.

The area inhabited by a species.


Define the term “population”.

A group of organisms of one species that live in the same place at the same time.


Define the term “species”.

A group of organisms which have a common ancestor and can interbreed to produce fertile offspring.

It is the smallest and most specific taxonomic group.


Define the term biodiversity.

The variety of living organisms present in an area.


Define the term “habitat biodiversity”.

The number of different habitats found within an area.


Define the term “species biodiversity”.

The number of different species and the abundance of each species in an area.


Define the term “genetic biodiversity”.

The variation of alleles within a species (or a population of a species).


State the 3 levels of biodiversity.

Habitat, species, and genetics.


Name 3 examples of different habitats.

- Meadow
- Woodland
- Streams


Define the term “sampling” and explain why it is important.

Taking measurements of a limited number of individual organisms present in a particular area.
Sampling can be used to estimate the number of organisms in an area without having to count them all.
Can also be used to measure a particular characteristic of an organism e.g. the height plants.


State the two general ways in which sampling can be undertaken.

- Random sampling.
- Non-random.


Define the terms “random sampling”.

Studying a representative sample of organisms in their natural habitat. Each organism has an equal chance of being selected.


Define the term “non-random sampling”.

The sample of organisms is not chosen at random, it can be opportunistic or stratified, or systematic. Some organisms have more chance than others of being selected for the sample.


Outline how to randomly sample an area.

Random sampling uses a quadrat.

1. Mark out a grid with xy axises on the area you are sampling and choose random co-ordinates from this grid.
2. Place the quadrat according to the first set of co-ordinates.
3. Use an identification key to identify the species present within the quadrat.
4. Record identified species and th abundance of each species in a suitable table and repeat until enough data is collected to calculate a reasonable estimation of the population size of each species within the area.


Name and describe the 3 main techniques of non-random sampling.

Opportunistic sampling - Samples whatever organisms are conveniently available. Weakest form as it is not always representative of the population.

Stratified sampling - some populations can be divided into a number of strata (subgroups) based on their characteristics. A random sample is then taken from each of these strata proportional to its size.

Systematic sampling - different areas within an overall habitat are identified which are then sampled separately.


Define the term “frame quadrat”.

A square rigid structure of a fixed size used to identify an area to be sampled, it is usually divided into a grid of equal sections.


Define the term “point quadrat”.

A horizontal bar set at intervals with 10 long pins, which can be lowered to the ground to take a sample. Every species that the pins touch is recorded as present for that particular sample.

This method uses the ACFOR scale to measure the abundance of each species.


Define “line transect”.

This involves marking out a line along the ground between two poles and taking samples at specified points.


Define the term “belt transect”.

Two parallel lines are marked and samples are taken from the area between the two lines. Provides more information than the line transect.


Define the term “interrupted belt transect”.

Uses a frame quadrat at specific intervals along a line transect.


Explain when random sampling would be appropriate and when systematic sampling would be appropriate.

Systematic sampling would be more useful in very big habitats, as it takes samples from different areas within an overall habitat. Would be more representative of the species diversity
Random sampling would be more appropriate for a smaller habitat.


Describe five ways to sample animals.

- A pooter, used to catch small insects by sucking on a mouthpiece which draws insects into a holding chamber via an inlet tube.

- Sweep nets, used to capture insects in long grass.

- Pitfall traps, used to catch small crawling invertebrates in a whole which is dug in the ground. Must be deep and covered with a roof structure to prevent drowning.

- Tree beating, a large white cloth is stretched out under the tree. The tree is shaken or beaten to dislodge invertebrates.

- Kick sampling, the river bank and bed is kicked for a period of time to disturb the substrate. The net is held downstream for a set period of time in order to capture any organisms released into the flowing water.


Describe 2 ways to sample plants (and sessile, or very slow moving, animals).

A point quadrat and a frame quadrat.


Describe 3 ways of collecting data using a frame quadrat (that could be applied to either random or non-random sampling).

- Density, count the number of plants in a quadrat which will give you density per square meter. This is an absolute measure, not an estimate.

- Frequency, individuals members of a species are hard to count (grass), so using small grids within a quadrat count the number of squares a particular species is present in.

- Percentage cover, this is for speed as lots of data can be collected when a particular species is abundant or difficult to count. An estimate by eye of the area within a quadrat which a species covers.


Define the term “abiotic factor”

non-living conditions in a habitat


Define the terms “biotic factor”

The living components of an ecosystem.


Name, and state the equipment used to measure, 6 abiotic factors that could be measured when studying the abundance and distribution of organisms in an area.

- Wind speed: anemometer (m/s)
- Light intensity: lightmeter (lx)
- Relative humidity: measured with a humidity sensor (dm-3)
- PH: ph probe (PH)
- Temperature: temperature probe (degrees c)
- Oxygen content in water: dissolved oxygen probs (mgdm-3)


Explain why a temperature probe linked to a data-logger may be advantageous over the use of a thermometer when investigating factors affecting the abundance and distribution of organisms in an area.

- Rapid changes in temp can be detected.
- Human error in taking measurements is reduced.
- A high degree is precision can often be obtained.
- Data can be stored and tracked.