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OCR A-level Biology > Biodiversity > Flashcards

Flashcards in Biodiversity Deck (58)
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What is Biodiversity?

The measure of the range in different plants, animals fungi and other microorganisms in the world


What is a habitat?

A place where individuals in a species live


What is habitat biodiversity?

The range of different habitats in which species live


What must a species be able to do to count as a real species?

Produce fertile offspring


What are the two types species biodiversity?

Species Richness
Species Evenness


What is species richness?

The number of different species in a habitat


What is species evenness?

How many of a species is in an area in relation to other species


What is genetic biodiversity?

The variation between individuals in the same species


Give an example of a species where there is lots of genetic biodiversity


A range of different breeds that can be completely different in size, appearance and behaviour


What are the different types of sampling?


Non Random:


How would you carry out random sampling?

Divide area into grid

Use a random number generator to create coordinates for areas to sample


What are the advantages and disadvantages of random sampling?

Pros - Reduces Bias

Cons - May not cover all areas of a habitat equally


How would you carry out Opportunistic sampling?

Sampler decides to study a certain area based on prior knowledge

May deliberately sample an area that they can see contains a particular species


What are the advantages and disadvantages of opportunistic sampling?

Pros - Quick and easy

Cons - Data may be biased as sampler may study more bright species that catch the eye


How would you carry out Stratified sampling?

Divide the habitat into areas that appear different (Grass and bracken would be separated)

Sample these areas individually


What are the advantages and disadvantages of stratified sampling?

Pros - Ensures all areas of a habitat are sampled fairly

Cons - Some small areas of the habitat may become over represented


How would you carry out systematic sampling?

Samples are taken at fixed intervals across the habitat

Line and Belt transects are used for this


What are the advantages and disadvantages of systematic sampling?

Pros - very useful when measuring the effect of a factor (like a pond) on the habitat

Cons - Only species on the line or within the belt are counted so some may be under-represented


Why might it be important to use a range of different sampling techniques?

Random sampling is required to ensure there is no bias

However, if the area is not homogenous (even) for example one area is nearer to a water source, then stratified sampling could help to show these differences


When might you use a quadrat?

When measuring the ground cover of a certain species of plant

Normally when the plant is too small to be easily counted (different flowers, weeds etc)


What is a quadrat?

A square frame that is used to estimate the number of individual plants in a habitat or the percentage cover of that organism


What is a transect?

A line taken across the habitat

You measure off this line and it is used to measure changes in distribution along the line


What is the difference between a line and a belt transect?

In a line transect you would lay out the line and then measure all the things touching the line at set intervals

Whereas, in a belt transect you would lay out the belt and then measure along the belt using quadrats at set intervals


Why can it be difficult to measure the the distribution of animals?

Large animals can sense your presence before you see them and hide

Smaller animals like insects can also sense your presence and are often too small too count accurately


How might you measure the distribution of different insect in a field?

Measure out a random area in the field

Use sweep nets in this area to catch insects in the grass

Empty the contents of the net onto a white sheet to easily count the insects


What is a pooter used for?

To collect insects that you have caught in a sweep net so that you can count them easily without them flying away


How might you measure the distribution of insect in a tree?

Lay out a white sheet on the floor

Hit the tree with a stout stick

Collect the fallen insect in a pooter


What is a Tullgren Funnel and how might you use it?

Place leaf litter into the funnel

A high above it dries it out and warms it up which drives the insects downwards

They will fall through a mesh and into a jar beneath the funnel


How could you estimate populations of larger animals?

Using mark-and-recapture technique

Capture a sample number of animals and mark all of them

Wait a period of time and Capture another sample of animals

Total pop = no. of 1st capture x no. of 2nd capture / no. of marked in second capture


How could you calculate genetic diversity?

Calculating the number of loci in one individual that are heterozygous


Give examples of human factors affecting biodiversity

Human population growth


Climate Change


How has human population growth impacted biodiversity?

We demand more food and consumer goods than other animals

We use the environment to our advantage and alter ecosystems to provide ourselves with food

As a result we often impact ecosystems greatly and reduce biodiversity


How has agriculture impacted biodiversity?

Modern agriculture relies on monoculture (growing one species) and selective breeding which both reduce biodiversity

Monoculture reduces the natural species richness and species evenness

Selective breeding reduces genetic diversity as it favours individuals with one specific characteristic meaning the species can be less adaptable to change


What is genetic erosion?

Where selecting for specific characteristics makes others rarer and they can die out

This reduces the size of the gene pool and is called genetic erosion


How is climate change impacting biodiversity?

Changes in environment put stress on organisms

Only the ones who adapted to this change are surviving

The ones who are not adapted are dying

This is reducing the gene pool


Why are agricultural crops particularly at risk from climate change?

We have genetically engineered the crops to produce high yield in a particular environment (the current environment)

This means they lack genetic variation so a very few of them would be able to cope if there were a change in environment

So climate change would put stress on a higher proportion of the population


What has happened to the rate of extinction in recent years?

It is rising rapidly

Humans are destroying habitats and thus greatly reducing biodiversity which is causing extinction

20% of all species alive today could be extinct by 2030


Why might a more complex habitat with more species diversity be able to withstand change better than a simple habitat with less diversity?

Because there is great interdependence between species

Many species feed off another or vice versa

In a complex habitat, other similar species may be able to replace one if it starts to fall in numbers

e.g If a bird feeds off a range of insects, and one particular insect species falls in numbers. They can simply eat more of another species


What is a keystone species? give an example.

A species that has a disproportionate impact on their environment compared to their abundance

A predator that limits the population of herbivores so that vegetation isn't overgrazed

If this predator is lost then it will have catastrophic impacts on all the other species in that environment


Why could the beaver be considered a keystone species?

Beavers build dams that trap water and flood the area behind, creating a still water pool.

This creates a completely new habitat where many different species thrive

If the beaver were to die out the dams would fall and the water would become fast-flowing which would destroy many of these species


Give some important reasons to maintain biodiversity?

biodiversity provides genetic diversity, these genes could be used to develop medicines for incurable diseases

We need biodiversity to maintain our atmosphere and allow us to grow crops

Aesthetic value of the environment may be lost


What is conservation?

Aims to help endangered species survive in order to maintain biodiversity


What is conservation in situ?

Conservation that is done in the natural habitat of the species


What is conservation ex situ?

Conservation that takes place outside the natural habitat of the species


Give some examples of different types of conservation in situ

Legislation - passing laws to stop activities such as hunting or logging. This should allow a population to grow naturally

Wildlife Reserves - designated areas for the conservation of habitats and species


How might conflict arise from nature reserves?

Animals coming out of the reserve to raid crops

People continue to hunt protected animals (poaching)

Illegal harvesting of timber and other plants

Tourists feeding protected animals to leaving litter


Give some examples of wildlife reserves in the UK

National parks - protected areas of the most beautiful areas of countryside that anyone can visit

National Nature Reserves - Protect sensitive features of the environment and enable research and education

Sites of Special Specific Scientific Interest (SSSI's) - Areas that are protected so that research into them can be continued

Local Nature Reserves - smaller scale, run by local councils

Marine Conservation Zones - Protected areas in the sea in order to protect endangered marine species


What are the advantages of in situ conservation?

Conserved in their natural environment

The biodiversity that is protected is truly representative of the original habitat

Protects natural and cultural heritage

Allows management of natural habitats so that integrity is maintained

Facilitates scientific research

May be possible to reverse negative impacts on the habitat and restore natural integrity


What are the disadvantages of in situ conservation?

Endangered habitats may be fragmented which could reduce the chances of survival

The population may have already lost a lot of its genetic diversity

The conditions that caused the species to become endangered may still be present

The area can become rife with poachers and tourists who cause disturbance in the habitat


Give examples of conservation ex stiu


Seed Banks

Botanic Gardens


What is the aim of zoos in terms conservation

They aim to to increase the numbers of endangered species through captive breeding programmes

With the hope to reintroduce them back into the wild in the future

They can also conduct research into these species to help them in the future


What are the advantages of ex situ conservation?

Individuals protected from poaching

Health of the individual is monitored and they can receive medical assistance if needed

Genetic diversity of the population can be measured

Selective breeding can be done to increase genetic diversity

In vitro fertilisation can be used to increase the chances of reproductive success

they can be bred to increase the numbers of an endangered species

The sites can be used as tourist attractions to raise funds for future projects

Sites can be used for education


What are the disadvantages of ex situ conservation?

A captive population will always have limited genetic diversity

Animals can be exposed to a wide range of diseases

They are living outside their natural habitat

Nutritional issues can be hard to manage

Animals may not behave normally when raised in captivity

The correct environmental conditions may be hard to achieve

Can be very expensive

There is no guarantee that the individuals will survive reintroduction to the wild


Why is the conservation of plants often easier than that of animals?

Most plants will have a dormant stage (as a seed) which is easy to maintain:

Seeds can be collected with little disturbance to the wild

Seeds can be easily stored

Plants often breed asexually

A botanic garden can increase the numbers of a species very quickly through tissue culture


What is the largest, ex situ conservation project in the world?

The millennium seed bank

contains seeds from every plant species known to man


What conditions are the seeds at the millennium seed bank stored in?

Very dry and freezing conditions

This provide the longest storage time


What is CITES and what do they aim to do?

The Convention on International Trade in Endangered Species

It aims to:
Regulate and monitor trade in species of plants and animals

Ensure trade does not endanger the survival of them

Ensure trade of wild plants for commercial purposes is prohibited

Ensure correct permits are held by those trading in plants and animals


What are the Countryside Stewardship Scheme and the Environmental Stewardship Scheme?

A scheme to help improve natural beauty, restore habitats and improve public access in the UK

Payments were given to farmers to replant hedgerows, rebuild drystone walls and to protect their land