11 Biodiversity Flashcards
Which three levels can biodiversity be studied at?
- Habitat biodiversity
- Species biodiversity
- Genetic biodiversity
What is habitat biodiversity?
Habitat biodiversity refers to the number of habitats found within an area
What are the two types of species biodiversity?
Species richness, and species evenness
What is species richness?
The number of different species living in a particular area
What is species evenness?
evenness of abundance across the different species present
What is genetic biodiversity?
Genetic biodiversity refers to the variety of genes that make up a species.
variation between individuals of same species
- measured by polymorphic gene loci/total gene loci
What is sampling?
Sampling means taking measurements of a limited number of individual organisms present in a particular area.
What is random sampling?
- Random sampling is a sampling technique where individuals are selected by chance.
- Each individual in the population has an equal likelihood of selection.
- To decide which organisms to study, random number tables or computers can be used
An example of a random sampling method:
1) Mark out a grid on the grass using two tape measures laid at right angles.
2) Use random numbers to determine the x coordinate and the y coordinate on your grid.
3) Take a sample at each of the coordinate pairs generated.
What is non-random sampling?
Non-random sampling is a sampling technique where the sample is not chosen at random.
What are the 3 main non-random sampling techniques?
Opportunisitic, systematic, stratified
What is opportunistic sampling?
- The weakest form of sampling as it may not be representative of the population.
- It uses organisms that are readily available.
What is systematic sampling?
- samples are at fixed intervals , measures changes in distribution along an axis
- Involves a line or belt transect.
What is stratified sampling?
Some populations can be divided into a number of strata (sub-groups) based on a particular group.
Why is a sample never entirely representative of the organisms present in a habitat?
1) Sampling bias- the selection process might be biased e.g choosing to sample a particular area because it has more flowers. Effects can be reduced by random sampling
2) Chance- the organisms selected might not be representative of the whole population. This can be minimised by using a large sample size.
What is a pooter?
- A pooter is used to catch small insects.
- By sucking on a mouthpiece, insects are drawn into the holding chamber via the inlet tube.
- A filter before the mouthpiece prevents them from being sucked into the mouth.
What are sweep nets?
Used to catch insects in areas of long grass.
What are pitfall traps?
- Pitfall traps are used to catch small crawling invertebrates such as spiders, beetles and slugs.
- A hole is dug into the ground which the insects fall into.
- It is covered with a roof-structure so the trap does not fill with rainwater.
What is tree beating?
- Tree beating is used to take samples of the invertebrates living in a tree or bush.
- A large white cloth is stretched out under the tree
- The tree is shaken or beaten to dislodge the invertebrates.
- The animals will fall onto the sheet where they can be collected and studied.
What is kick sampling?
- It is used to study the organisms in a river.
- The river bank and bed is ‘kicked’ for a period of time to disturb the habitat.
- A net is held just downstream for a set period of time in order to capture any organisms released into the flowing water.
What are the two types of quadrats?
Point quadrat and frame quadrat
What is a point quadrat?
- This consists of a frame containing a horiziontal 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
What is a frame quadrat?
- This consists of a square frame divided into a grid of equal sections.
- The type and number of species within each section of the quadrat is recorded.
What are abiotic factors?
Abiotic factors are the non-living conditions in a habitat.
What is the Simpson’s Diversity of Index?
A measure of biodiversity between 0 and 1 that takes into account both species richness and species evenness.
What is the formula for Simpson’s Diversity of Index?
D= 1- Sum of (n/N)^2
For genetic biodiversity to increase, the number of possible alleles in a population must also increase. This can occur through:
- Mutation in the DNA of an organism, creating a new allele
- Interbreeding between different populations - increased in gene flow
For genetic biodiversity to decrease, the number of possible alleles in a population must also decrease. This can occur through:
- Selective breeding where only a few individuals are selected for their advantageous characteristics
- cloning
- captive breeding
- Natural selection as species will evolve to contain primarily the alleles which code for advantageous characteristics. Over time, alleles coding for less advantageous characteristics will be lost from population.
- Genetic bottlenecks, where few individuals within a population survive an event or change,thus reducing the gene pool
- The founder effect, where a small number of individuals create a new colony, geographically isolated from the original.
- random genetic drift - random nature of genes being passed on
How do we calculate the proportion of polymorphic gene loci?
Number of polymorphic gene loci/ Total number of loci
What is conservation?
The preservation and careful management of the environment and of natural resources.
What are the main two categories of conservation?
In situ & ex situ conservation
What is in situ conservation?
Conserving within the natural habitat
E.g wildlife reserves, marine conservation zones
What is ex situ conservation?
Conserving out of the natural habitat
E.g botanic gardens, captive breeding programmes, seed bank
What is sustainable development?
Economic development that meets the needs of people today, without limiting the ability of future generations to meet their needs.
What are some active management techniques in wildlife reserves?
- Controlled grazing: Only allowing livestock to graze a particular area of land for a certain period of time
- Restricting human access
- Controlling poaching
What does the International Union for the Conservation of Nature (IUCN) do?
- Publishes the Red List at least once a year, detailing current conservation status of endangered animals so countries can work together to conserve the species.
What is the Convention of International Trade in Endangered Species? (CITES)
Its aim is to control the trade of endangered species and their associated products. For example, elephants and their ivory tusks
- regulate, monitor and prevent trade of endangered species
- prohibit (commercial) trade in wild plants ; allow (some) trade in less endangered , wild species
What is the Rio Convention?
Creates agreements between nations
- sustainable use of , organisms / habitats / ecosystems for example sustainable fishing
- sharing access to scientific knowledge and technology
What is the countryside stewardship scheme?
- Farmers are paid governmental payments to enhance and observe the English landscape
E.g improving, extending, creating wildlife habitats
Restoring neglected land
Maintaining the beauty and diversity of the landscape
What would we use to test for correlation between two sets of data?
Spearmans rank
What would we use to test for significance of difference between two values or means?
T-test
What would we use to test for significance of associations between categorical data?
Chi squared
Outline the significance of a low value of Simpson’s Index of Diversity.
habitat is dominated by one/few species,
change in one species , likely to affect whole habitat thus ecosystem is unstable and less likely to cope with change
explain the importance of sampling
counting every individual is too time consuming and difficult, sampling provides an estimate and is representative of whole area
Explain why it is sometimes necessary to conserve a plant species outside its natural habitat (ex situ).
(natural) habitat / ecosystem , lost due to / destroyed by / under threat from , climate change /
reason
natural disaster / deforestation , as reason for habitat loss
(named) human activity ;
number / population , (in natural habitat) is very low ;
(breeding ex situ can) maintain , the gene pool / genetic / allelic , diversity
allows protection from , grazers / herbivores / plant collectors / competing species ; ora
protection from , predators / poachers / hunters
idea of protection from pathogen / parasites / disease
Give three advantages of conserving plant species as seeds and not as adult plants.
less , susceptible / vulnerable , to, disease / pests / environmental change
take up little space / larger numbers can be stored
ow(er) maintenance / manpower costs, less labour-intensive
can be collected with minimal damage to (wild) ,
population / habitat / ecosystem
Outline an unbiased sampling method that can be used to measure the biodiversity of plant species in grassland.
use frame quadrat
place measuring tapes at right angles
randomly generate coordinates using a number generator and place quadrants at coordinates
repeat many times
sample at different , seasons / times of year
Scientists try to estimate the total number of species on Earth.
Suggest three reasons why such estimates are not likely to be accurate.
reason for not having found all species
may have become extinct , recently / since recording ; evolution is on-going / new species are being formed
species can be difficult to distinguish - might mistake several species for one
define biodiversity
range / variety / number , of species (in an area)
range / variety of, habitats / ecosystems ; variety of , alleles / genes
sampling animals
- pit fall traps
- pooter
- sweep nets
- catch and release recapture method with live animals
catch and release recapture method and formula
catch , mark them , then second catch and see how many have marks on them formula : C1 X C2 / CM c1= fist capture c2= second capture cM = marked number in second capture
The proportion of polymorphic gene loci is the
The number of loci that have two or more alleles
why is genetic diversity important within a population
Diversity in a species is important as it creates a larger gene pool which can help the population adapt, and survive changes in the environment
The changes could be biotic factors such as new predators, pathogens and competition with other species or they could be abiotic factors like temperature, humidity and rainfall
factors affecting biodiversity :
human population growth
agriculture (monoculture)
climate change
human population growth
The global human population has been growing exponentially
There are many reasons for this exponential growth, including:
Improved technology leading to an abundance of food = increase in birth rate
Improved medicine, hygiene and health care = decrease in death rate
The main factors affecting biodiversity today are: Habitat destruction Overexploitation Hunting Agriculture Climate change
process of selective breeding
select male an female with desired characteristic
mate them together so they reproduce, select the best offsprings, breeding the best offsprings together
- process id repeated, breeding (and selecting) for , many / several
Suggest how organic fertilisers improve the yield of plant crops
broken down by, decomposers / bacteria / fungi ; add (named) mineral(s) to soil ; nitrate and phosphate and potassium
lack of (named) , mineral(s) / nutrient(s) / ion(s), is
limiting factor for growth
organic fertilisers improve the soil quality in this way
overuse of fertiliser leads to reduced biodiversity
- might change soil pH so some plants can’t grow, reduces soil quietly over time so plants cannot grow
- (fertiliser) promotes growth of, one / few, (plant) species other (plant) species , out-competed
Explain why a reduction in biodiversity may present problems for agriculture in the future.
- loss of genetic , diversity / variation (in wild population) - - environment / agricultural requirements, may change (in future) ;
(lost) genes / alleles , may have been useful ;
e. g. of gene useful to agriculture like gene resistance to disease
Suggest why it is important to ensure that, for each species, the seeds in a seed bank have been collected from several different sites in the wild.
maintain / increase) genetic variation / gene pool ;
reduced chance of (future), disease / environmental change, affecting (whole) population ;
reduces chance of inbreeding ;
maintain, geographical variation
Aphids can be killed using an insecticide. However, over a period of time, an increasing concentration of insecticide is required to control the aphid population.
Explain why this is the case
natural selection process -
insecticide is the , selective agent / selection pressure ;
mutation in genes are randomly occurring
the ones with the mutation that is resistant to insecticide survive / non-resistant die ; (resistants will) pass on , allele / mutation , for resistance (to offspring)
higher proportion of / more , resistant individuals in population
Suggest two factors to be taken into consideration when selecting individuals for this breeding programme
healthy/fertile individuals
of reproductive age
unrelated individuals, ensure they are sufficiently genetically different
Finally, a captive bred female Spix’s Macaw was released into the original male’s territory. What could be done to try to ensure the success of this release programme?
birds are healthy before release (quarantine before release)
method to monitor the population (for example tag them)
method to prepare animals for survival in wild - raise with minimal contact from humans, eg: allow them to find own food
raise public awareness / educate local population
protected reserve / no hunting / no poaching
why ex situ over in situ ?
fed uncontaminated food
health of individuals monitored / treated for disease reduced mortality of young ;
mate / females breeding can be manipulated ;
protection , from hunting / predation ;
competition reduced (between , individuals / species
