Topic 4.2.1 Biodiversity Flashcards
What is a Habitat?
The place where an organism lives - organisms are often well-adapted to their habitats
What is Biodiversity?
- all plant, animal, fungus and microorganism species worldwide
- the genes these species contains
- the ecosystems they form part of
- number of individuals and the number of places they are found
What is Habitat Biodiversity?
The range of habitats in which different species live
What is Species Biodiversity?
- Species Richness
- no. of different species living in an area
What is Genetic Biodiversity?
- the variety of genes that form a species
- many individuals in the same species have the same genes
- for some genes different alleles exist
What is Species Richness?
the number of species found in a habitat - more species=richer habitat
What is Species Evenness?
a measure of the relative abundance or number of individuals in each species
What is the formula for the ‘mark-and-recapture-technique’?
- Total Population Formula
(C1 x C2) / C3
What sample is labelled as C1 in the ‘mark-and-recapture-technique’?
The number initially captured and harmlessly marked
What sample is labelled as C2 in the ‘mark-and-recapture-technique’?
The number captured the second time around after C1 has been released for a period of time
What sample is labelled as C3 in the ‘mark-and-recapture-technique’?
The number already marked within C2
Advantages of the ‘mark-and-recapture-technique’?
- quick to carry out
- measure large populations in less time
Disadvantages of the ‘mark-and-recapture-technique’?
- can be unreliable
- needs to be repeated
What is ‘Simpson’s Index of Diversity’?
a better method for measuring habitat diversity
What does ‘Simpson’s Index of Diversity’ take into account?
- species richness
- species evenness
What is the formula for ‘Simpson’s Index of Diversity’?
D = 1 - [sum (no. of individuals of a particular species / no. of individuals of all species)^2 ]
n in the ‘Simpson’s Index of Diversity’ formula represents what?
no. of individuals of a particular species or % cover for plants
N in the ‘Simpson’s Index of Diversity’ formula represents what?
no. of individuals of all species or % cover for plants
What does a high value from Simpson’s Index of Diversity show?
- a diverse habit
- the habitat is stable and able to withstand change
What does a low value from Simpson’s Index of Diversity show?
- the habitat is dominated by a few species
- a small change to the environment that affects one of the dominant species could damage or destroy the whole habitat
What is an abiotic factor?
Factors that don’t have living organisms as a source
Name some examples of abiotic factors
- wind speed
- light intensity
- relative humidity
- pH
- temperature
- oxygen levels
How does wind speed affect biodiversity?
- increases the supply of CO2 to the plant
- increases transpiration rate and therefore water loss
- can cause mechanical damage to plants
How is wind speed measured?
With an anemometer (ms-1)
How does light intensity affect biodiversity?
-plant species have evolved for optimum growth in the light available in their climate or habitat
How is light intensity measured?
With a light meter (Ix)
How does relative humidity affect biodiversity?
- most plants are killed by water Lolll logging meaning they can’t respite
- big plants are adapted to growing in wet conditions
How is relative humidity measured?
With a humidity sensor (mgdm-3)
How does temperature affect biodiversity?
- animals and plants have evolved to grow healthily at their optimum temperature
How is temperature measured?
Temperature probs (degrees Celsius)
What are the two types of sampling in plants?
- random
- non-random
What is random sampling?
- involves selecting individuals by chance
- each individual in the population has an equal chance of being selected
How is random sampling carried out?
using random number tables, generators or computers
What is non-random sampling?
- the sample taken is not chosen at random
- random sampling can be divided into three main techniques?
What are the three main techniques for non-random sampling?
- opportunistic
- stratified
- systematic
What is opportunistic sampling?
- the weakest form of sampling
- not representative of the population
- uses organisms that are conveniently available
what is stratified sampling?
- the population is divided into different strata based on particular characteristics
- random sample is taken from each strata proportional to its size
What is the definition of a ‘strata’?
a sub-group
What is systematic sampling?
- different areas within an overall habitat are identified, sampled separately
What is a transect?
- a line taken across the habitat
How does a Line Transect work?
- involves making a line along the ground between two poles and taking samples at specified points along the line
How does a Belt Transect work?
- two parallel lines are marked, samples are taken from the area between two lines
Does a line or a belt transect provide more information?
belt transect
What type of transect is used in a large habitat?
- line transect
- record the plants touching the line at set intervals
- belt transect
- place quadrats along the line and record the data
What are the two types of belt transect?
- interrupted
- continuous
How does an interrupted belt transect work?
- quadrats set at intervals along the line
- record data
What type of data does an interrupted belt transect provide?
- quantitative data at intervals across the habitat
How does a continuous belt transect work?
- quadrats beside the line without any intervals between them
What type of data does a continuous belt transect provide?
- quantitative data in a band or belt across the habitat
How are plants usually sampled?
using quadrats and the random sampling technique
When would a line or belt transect be best used?
in an environment that varies where you want to study the distribution of organisms
What are the three ways to sample when using frame quadrats?
- Density
- Frequency
- Percentage Cover
What is Density sampling when using a frame quadrat?
- used when plants can be easily counted
- each individual plant is counted so the results are far more accurate than an estimation like infrequency and percentage cover
What is Frequency sampling when using a frame quadrat?
- an estimate used when species are hard to count
- counting the number of squares that a species is present in
What is Percentage Cover sampling when using a frame quadrat?
- an estimate by eye of an area within a quadrat that a plant species covers
- can be quickly collected
How do Point Quadrats work?
- a frame containing a horizontal bar
- long pins can be pushed through the bar to reach the ground at set intervals
- each species of plant the pin touches is recorded
What is the impact of sampling bias on sampling and reliability?
reduces how representative the sample is of the whole habitat
What is the impact of chance on sampling and reliability?
a small sample size increases the likelihood of chance playing a part in the reliability - should always take from a larger sample
How do you sample biodiversity in animals?
- pitfall traps
- pooter
- kick sampling
- sweep net
- tree beating
What are pitfall traps?
- used to catch small invertebrates such as beetles, spiders and slugs
- a hole deep enough so the samples can’t climb back out is dug into the ground which insects fall into
What is a pooter?
- used to catch small insects for identification
- you put it in your mouth and suck the insects into the holding chamber through the inlet tube
What is kick sampling?
- used to study the organisms living in a river bank
- the river bank is kicked for a period of time to dislodge the organisms
What is a sweep net?
- used to catch insects in areas of long grass
What is tree beating?
- used to sample invertebrates living in or on trees
- a large white cloth is stretched out under the tree and the tree is shaken or beaten
What technique is often used to estimate animal population size?
capture-mark-release-recapture
What are alleles?
- all members of the same species share the same genes
- different versions of the same genes are called alleles
What is another name for alleles?
polymorphisms
What is genetic biodiversity?
- differences in the alleles creates genetic biodiversity within the species
- the more alleles present in a population the more genetically biodiverse the population
Where are genes found?
- a gene can be found in a particular position on a chromosome
- different individuals may have different alleles for a particular gene
What is the point at which a gene can be found on a chromosome called?
the locus (plural - loci)
How does genetic biodiversity increase?
the number of possible alleles in a population also increase
How does mutation affect genetic biodiversity?
creates greater variation within the base DNA present in a particular species - more alleles present in the genes
How does interbreeding affect genetic biodiversity?
different species that contain varying genes and alleles breed which will increase genetic biodiversity of their offspring
How does genetic biodiversity decrease?
the number of possible alleles in a population much also decrease
How does selective breeding lead to a decrease in genetic biodiversity?
- choosing the exact genes that will be passed to the offspring decreases variation
- doesn’t allow for natural mutations or interbreeding
How do captive breeding programmes lead to a decrease in genetic biodiversity?
- decreases the genes available to create variation through reproduction
How do rare breeds decrease genetic biodiversity?
- only a limited gene pool available for reproduction through the limited species density
- not many organisms within the species
How does artificial cloning decrease genetic biodiversity?
- cloning an identical copy of an organism
- eliminates all variation
How does natural selection decrease genetic biodiversity?
- eliminates the less advantageous alleles within a species as they are less likely to survive and reproduce in their habitat
How do genetic bottlenecks decrease genetic biodiversity?
- a catastrophic event eliminates a large portion of the genetic variation within a species
- only a few organisms and their genes can reproduce
How does the founder effect decrease genetic biodiversity?
- a more limited gene pool available for reproduction will limit the variation within the species population
- over time mutation will increase genetic biodiversity
How does genetic drift decrease genetic biodiversity?
- involves the loss of alleles from a population by chance
- random fluctuation in allele frequencies in small populations
What is polymorphism?
a discontinuous genetic variation resulting in the occurrence of several different forms or types of individuals among the members of a single species
How do you measure genetic biodiversity within a population?
- gel electrophoresis
- measures the polymorphic genes (more than one allele)
What are the steps of Gel Electrophoresis?
- Restriction enzymes cleave DNA into smaller segments of various sizes
- DNA segments are loaded into wells in a porous gel - the gel floats in a buffer solution within a chamber between two electrodes
- When an electric current is passed through the chamber, DNA fragments move toward the positively-charged cathode
- Smaller DNA segments move faster and father than larger DNA segments
What three types of reason are there to maintain genetic biodiversity?
- aesthetic reasons
- economic reasons
- ecological reasons
What aesthetic reasons are there for maintaining genetic biodiversity?
- enriches our lives
- provides inspiration
- recovery from injury or stress
What economic reasons are there for maintaining genetic biodiversity?
- soil erosion and desertification
- loss of potential medicines or chemicals
- soil depletion from monoculture - increasingly dependant upon herbicides and fertiliser
- protects against biotic stresses - disease, natural disasters
- promote tourism
- greater varieties allows for cross breeding for favourable characteristics
- conserve organisms we use to make things
What ecological reasons are there for maintaining genetic biodiversity?
- interdependence - all organisms depend on each other in a food chain
- keystone species - some species play a key role in the structure of the community
What are the three main factors affecting biodiversity?
- deforestation
- agriculture
- climate change
What causes deforestation?
How does deforestation affect biodiversity?
What causes issues surrounding agriculture?
How does agriculture affect biodiversity?
What causes climate change?
How does climate change affect biodiversity?
What is conservation in-situ?
What is an example of in-situ conservation?
What active management techniques are used in wildlife reserves?
What are some benefits of in-situ conservation?
What is conservation ex-situ?
What are some examples of ex-situ conservation?
Describe botanical gardens as a method of ex-situ conservation.
Describe seed banks as a method of ex-situ conservation.
Describe captive breeding as a method of ex-situ conservation.
What are some advantages of Captive Breeding Programmes?
What are some disadvantages of Captive Breeding Programmes?
What is the International Union for the Conservation of Nature?
What was the Rio Convention?
What was the Countryside Stewardship Scheme?
