Unit 2: Biodiversity Flashcards Preview

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Flashcards in Unit 2: Biodiversity Deck (103)
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Define species

Individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics, whose members are able to interbreed freely to produce fertile offspring


Define niche

The role occupied by an organism in a particular ecosystem, dependant on the resources it uses


Define habitat

The place where an organism lives


Define biodiversity

The variety of life
Species richness and species evenness


Define ecosystem

All the biotic and abiotic factors in a specific area and their interactions


What are biotic and abiotic factors?

Biotic= living factors eg predators, disease, other species
Abiotic= physical/non-living eg light intensity, soil and minerals, soil pH, soil moisture, temperature


What is species richness and species evenness?

Species richness= the amount of different species
Species evenness= the amount of individuals in each separate species


What are the differnt levels of biodiversity?

Range of habitats
Differences between species
Genetic variation


What is random sampling?

Studying a part of a habitat and assuming it obtains a representative set so species found in the whole habitat


Why is it important to do random sampling?

Avoids bias in results of a survey


How many samples should be taken?

Dependant on size and time avaliable
Football pitch= 10 1metre squared samples
Wild meadow= 20 1metre squared samples

If comparing 2 or more areas, take the same number of samples!!


What is the ACFOR scale?



How can quadrants be used to measure abundance?

Using a grid of strings/point frame you can estimate % cover


What are the advantages and disadvantages to using a point frame?

:) Gives more accurate % estimate
:) more detailed

:( time consuming
:( as one needle may touch several plants, may give 300-400%


How do you use a point frame?

Frame holds 10 long needles
Frame lowered into quadrat and number of species touching needle is recorded
Frame with 10 needles used 10 times gives 100 readings=100% coverage


What are he two types of transect?

Interrupted belt transect-May use quadrats at set intervals from transect

Continuous belt transect-quadrats moved along the line


What is the problem with sampling animal habitats? How can this be solved?

Animals will move due to disruption to the habitat or hide if they detect presence of larger animals (humans)

Can be solved by trapping and sampling smaller animals whilst larger animals should just be carefully observed


What is a sweep net used for?

Used for catching small animals like insects
Suitable for low vegetation and water


How is a pooter used?

Used to collect insects caught in sweep net
Sucked up into observation chamber, prevents insect from crawling/flying away


How is a pitfall trap used?

Trap is set in soil, hidden to catch any small animals/insects
Trap should have some water/scrunched up paper to stop the animals crawling out


How is a till green funnel used?

Used to collect small animals from leaf litter
Leaf litter placed underneath a bright light source, small animals driven downwards which fall through a mesh into a jar with preservative in


Why do we sample?

Human activity affects the environment in many ways-unless we sample, we can't assess the effect we have
Reduce damage to habitats by estimating effect of planned development on the environment


What should you cover in an exam question asking to sample plants/sessile animals?

% cover/ACFOR
Random sampling
Map out area and select random coordinates (inc. method to do this)
Measuring tape to measure area
Record results in pre-prepared table
If covering 2 areas-same # and time for samples
Repeat sampling at different times of year


Using Simpsons diversity index, what does a high/low value indicate?

0=no biodiversity
1=high biodiversity


What are the advantages to using the Simpsons diversity index?

Don't need to know the species type
Species diversity is in relation to numbers of different species not just overall numbers


What is a plagioclimax?

Where human activity can increase the variety of species found in an area above natural levels


Give an example of a plagioclimax

A field with regularly cut grass
-> Dominant species is removed=less competition and more light can get to smaller windflowers
-> More species can do photosynthesis
-> Attracts more insects


What factors can affect how well a plant survives?

Amount of light
pH of soil
Soil mineral ion content
Condition of soil (compact or loose)


How can trees affect biodiversity?

Tree out competes grass for light and soil minerals
Tree alters pH and structure of soil


How are species sometimes underestimated in sampling?

Some plant species look similar
Some species are easier to spot than others
Do species count if only partially in quadrat?
Not all species present/flower on same day but seeds still in soil