B11 - Biodiversity Flashcards
1
Q
What is biodiversity?
A
- the variety of living organisms living in an area
- includes plants, animals, fungi and other living things
2
Q
What are the different levels of biodiversity?
A
- habitat
- species
- genetic
3
Q
What is habitat biodiversity?
A
- the no. of different habitats within an area
- each habitat can support a no. of different species
- UK = larger no. of habitat types
- Antarctica = very low habitat biodiversity
4
Q
What is species biodiversity?
A
- species richness = no. of different species living in an area
- species evenness = a comparison of the numbers of individuals of species living in a community
- having the same no. of species does not mean that they have the same species biodiversity
- if the majority of the population is one type of species, the region has a low species biodiversity
5
Q
What is genetic biodiversity?
A
- the variety of genes that make up a species
- different versions of genes (alleles) lead to genetic biodiversity
- this can lead to different characteristics being exhibited
- greater genetic biodiversity allows for better adaptation to a changing environment (more resistant to disease)
6
Q
What is sampling?
A
- taking measurements of a limited no. of individual organisms present in a particular area
- can be used to estimate the no. of organism in an area
-
abundance = no. of species present in an area
- it can also be used to measure a particular characteristic (calculate average)
7
Q
What is random sampling?
A
- selecting individuals by chance
- no involvement in deciding which organisms to investigate
- make a grid in grass with two tape measures (right angles)
- random numbers to determine x and y coordinate
- take sample at each coordinate
8
Q
What is non-random sampling?
A
- sample is not chosen at random
- opportunistic sampling = uses organisms that are conveniently available (not very representative of the population)
- stratified = populations divided into sub groups based on particular characteristic, random sample (proportional) is then taken from each
- systematic = carried out using belt/line transect
- line = marking line along ground between two poles
- belt = parallel lines are marked (sample taken from both sides)
9
Q
What affects reliability of sampling?
A
- sampling bias:
- selection process may be biased
- e.g. you may choose to sample an area with more flowers
- random sampling can reduce this
- chance:
- organisms selected may not be representative of the whole population
- chance cannot be completely removed but its effect can be minimised by using a larger sample
10
Q
How are animals sampled?
A
- as soon as the organisms have been counted and measured, they must be released back into the environment they were collected
- pooter:
- catches small insects by sucking on mouthpiece
- filter prevents them entering the mouth
- pitfall traps:
- catches small, crawling invertebrates
- hole is dug into ground and insects fall in
- roof-structure prevents build up of water
- traps are left overnight (nocturnal species are also captured)
- tree beating:
- samples invertebrates living in a tree/bush
- large white cloth stretched out to catch the organisms
- kick sampling:
- studies organisms living in a river
- river bank/bed is kicked and this disturbs the substrate
- net is held downstream to catch the organisms
11
Q
How are plants sampled?
A
- usually sampled using a quadrat
- can also be used to sample slow moving animals
- point quadrat:
- frame with a horizontal bar
- at set intervals, there are long pins that can be pushed through to reach the ground
- each plant touching it is recorded
- frame quadrat:
- square frame divided into equal sections
- type and no. of species is recorded
- a random sampling technique should be used
- to study how the presence/distribution of organisms vary, the quadrants can be placed systematically along a line/belt transect
12
Q
How to measure species richness?
A
- combination of techniques should be used
- list all species identified
- total no. of species can be calculated
- to accurately identify them, identification keys are used
- they classify organisms based on identifiable characteristics
13
Q
How to measure species evenness?
A
- list all organisms found
- calculate the no. of organisms within each species
- e.g. 50 organisms = 20 woodlice, 15 spiders, 15 centipedes (evenly distributed)
14
Q
How are frame quadrats used?
A
- density:
- if large individual plants are clearly seen, count them in 1m by 1m quadrat and this gives the dentistry per square metre (absolute measure)
- frequency:
- used where individual members of a species are hard to count
- smaller grids are used to count no. of species within a quadrat
- if a species is present in 65 out of 100 squares, its frequency is 65%
- percentage cover:
- used for speed to collect data quickly
- useful if species is abundant/difficult to count
- it is an estimate by eye of the area
15
Q
How is animal population estimated?
A
- capture-mark-release-recapture is often used to estimate a population size
- capture as many individuals of a species as possible
- they are then marked and released
- time is allowed for them to redistribute themselves before another sample is collected
- they then compare the no. of marked/unmarked individuals compared to the first sample
- the greater the no. of marked individuals, the smaller the population
- species evenness is then calculated by comparing the total no. of each organism present
- populations of plants/animals that are similar in size/density represent an even community
- it can also be represented as a ratio between the no. of each organism present
16
Q
How are abiotic factors measured?
A
- e.g. light intensity and water availability
- measured at each sampling point
- wind speed = anemometer
- light intensity = light meter
- relative humidity = humidity sensor
- pH = pH probe
- temperature - temp. probe
- O2 content in water = dissolved O2 probe
- the advantages include:
- rapid changes detected
- human error is reduced
- high degree of precision
- data can be stored/tracked on a computer
17
Q
How is biodiversity calculated?
A
- diversity of organisms present in an area is proportional to the stability of the ecosystem
- species richness = no. of species present
- species evenness = the distribution of the no. of individuals within each species
- Simpson’s Index of Diversity (D) is used as it takes into account both richness and evenness
- D = 1 - (sum of) (n/N)^2
- N = total no. of organisms of all species
- n = total no. of organisms of a particular species
- ** a quadrat is often used to estimate the population of plant species in an area **
- ** always results in a value between 0 and 1 **
- 0 = no diversity
- 1 = infinite diversity
18
Q
Why is genetic biodiversity important?
A
- maintaining this is essential to the survival of a species
- those in a captive breeding programme have a reduced genetic biodiversity
- differences in alleles between individuals of the same species creates genetic biodiversity (more alleles = more genetically biodiverse)
- those with a greater genetic biodiversity are more likely to adapt to the changes (enables them to live in those conditions)
- this is because they have the advantageous allele that will them be passed on to their offspring
19
Q
What factors affect genetic biodiversity?
A
- increase no. of alleles:
- mutations in the DNA
- interbreeding between different populations (e.g. when an individual migrates from one population to another and alleles are transferred- gene flow)
- decrease genetic biodiversity:
- selective breeding = only a few individuals are selected for their advantageous characteristics and bred
- captive breeding programmes = a small no. of captive individuals are available for breeding
- rare breeds = no. of individuals with the less popular characteristics fall and the remaining population’s g.b.will be low (can cause problems when trying to restore numbers yet maintain heir characteristics)
- artificial cloning = asexual reproduction
- natural selection = species will evolve to contain advantageous traits and over time the less advantageous characteristics will fall
- genetic bottlenecks = few individuals within a population survive an event/change (reduces gene pool), only the alleles of the surging population will be passed onto the offspring
- founder effect = small no. of individuals create a new colony (geographically isolated), small gene pool
- genetic drift = frequency of occurrence of an allele will vary, existence of a particular allele can disappear from a population altogether
20
Q
How is genetic biodiversity measured?
A
- measure polymorphism (genes with more than one allele)
- e.g. different alleles exist for immunoglobulin gene
- prop. of polymorphic gene loci = no. of polymorphic gene loci / total no. of loci
21
Q
What is human influence on biodiversity?
A
- species are interconnected within an ecosystem, so the removal of one species can have a large effect on others
- deforestation = permanent removal of large areas of forest to provide wood for building/fuel
- agriculture = increasing amount of land has to be farmed in order to feed the growing population (monoculture has also occurred)
- climate change = release of CO2 and other pollutants is increasing global temperatures
- other forms of pollution result from industry/agriculture (e.g. chemical pollution of waterways)
- improper disposal of waste/packaging is also a type of environmental pollution
22
Q
How does deforestation affect biodiversity?
A
- can occur naturally (wild fires), but most of them happen deliberately
- directly reduces the no. of trees present in an area
- specific type of tree felled:
- species diversity is reduced
- reduces no. of animal species present in an area (destroys habitat, food, home)
- animals are forced to migrate to other areas
23
Q
How does agriculture affect biodiversity?
A
- farmers only grow a few different species of crop plants (based on characteristics)
- this greatly reduces the biodiversity of the area
- to be economically viable and no. of techniques are used to produce as many of the desired species
- deforestation:
- increases area of land for growing crops/rearing animals
- removal of hedgerows:
- enables them to use large machinery (plant, fertilise, harvest)
- reduces no. of plant species present and destroys habitat of animals such as black birds, hedgehogs and invertebrates
- use of chemicals such as pesticides, herbicides:
- pesticides = kills pests that eat crops or live in animals
- reduces pest species (indirectly by destroying food source of other organisms)
- herbicides:
- weeds are destroyed as they compete with cultivated plants for light, minerals and water
- plant diversity is reduced directly (animal diversity also reduced as they lose their food source)
- monoculture:
- production of only one crop will lower biodiversity as only one species is present
- relatively few animal species are supported by only one plant species
- growth or vast plant oil plantations is one of the leading causes of rainforest deforestation
24
Q
How does climate change affect biodiversity?
A
- increase in warming trend over the last 50 years
- increase in water vapour
- average sea level is rising
- melting of ice caps/glaciers
- decisions made will have consequences (e.g. reduces public transport)
- need to produce reliable data for issues this scale is paramount
- melting of polar ice caps:
- extinction of few plant and animal species
- rising sea levels/thermal expansion:
- could flood low lying land (reduces available terrestrial habitats
- higher temps./less rainfall:
- drought-resistant species will become more dominant (xerophytes)
- loss of non drought resistant species would less to a loss of some animal species that feed on them
- those species will then be replaced by other species that feed on xerophytes
- insect life cycles/populations will change:
- they are key pollinators and their extinction will affect the lives of the plants that they leave behind
- as climate change increases, tropical insects may become more dominant and they would carry their diseases to the poles
- if climate change is low, species may have time to adapt/migrate to new areas
- this will cause a loss of native species and other ones may move into the area (species mix will change)
25
Q
Why is it important to maintain biodiversity?
A
- aesthetic:
- presence of diff. plants and animals enriches our lives
- natural world provides inspiration
- patients recover more rapidly from stress and injury with the help of nature
- economic:
- soil erosion and desertification may occur due to deforestation (reduces country’s ability to grow crops and feed its people)
- important to conserve organisms used to make things (non-sustainable removal of materials will cause a collapse in the industry)
- large-scale habitat and biodiversity loss will mean that important species/organisms will be lost before they are even discovered (may be medically/chemically useful)
- continuous monoculture will result in soil depletion (no nutrients are left to be recycled, so crops that it can support will be weaker which increases their vulnerability)
- high biodiversity provides protection (low biodiversity means that a change in condition/disease will destroy entire crops, e.g. Irish potato famine)
- areas rich in b.d. will provide a pleasing and attractive environment (can promote tourism)
- greater the diversity, greater the potential for manufacture of different products (food production, cures/treatment)
- plant varieties are needed for cross breeding which leads to better characteristics such as disease resistance/increased yield (g.e. can also help to make crop plants/animals more efficient which reduces the land required to feed more people)
- ecological:
- all organisms are interdependent on others for their survival (removal of one species may have a big impact on others, loss of food source or place to live)
- keystone species are important for maintaining the structure of an ecological community, they affect many other organisms in an ecosystem (help to determine species richness and evenness)
26
Q
How is biodiversity maintained?
A
- conservation = the preservation and careful management of the environment/natural resources
- species and genetic diversity can be safeguarded
- in situ = within natural habitat
- ex situ = out of natural habitat
- extinct = no organisms of species exist anywhere in the world
- extinct in the wild = organisms of the species only exist in captivity
- endangered = species in danger of extinction (conservation is prioritised)
- vulnerable = species that is considered likely to become endangered in the near future
- sustainable development = economic development that meets the needs of people today (does not limit ability of future generations to meet their needs)
27
Q
What is in situ conservation?
A
- maintains the genetic biodiversity and their evolutionary adaptations
- by allowing endangered species to interact with other species, it preserves the interdependent relationships
- interlinked species can also be preserved
- cheaper than ex situ
examples:
- marine (saltwater)
- aquatic (freshwater)
- terrestrial (land)
28
Q
What are wildlife reserves?
A
- controlled grazing
- grazing a particular area of land will allow species time to recover
- restricting human access
- providing paths to prevent plants being trampled
- controlling poaching
- creating defences to prevent access, issuing fines, removal of rhino horns
- feeding animals
- ensures more organisms survive to reproductive age
- reintroduction of species
- adding species to areas that have become locally extinct
- culling/removal of invasive species
- these species compete with native species for resources
- halting succession:
- succession = natural process in which early colonising species are replaced over time
- this is an important role played by humans in maintaining habitats for future generations
29
Q
What are marine conservation zones?
A
- vital in preserving species-rich areas such as coral reefs
- used to create areas of refuge within which populations can build up and repopulate adjacent areas
- large areas of sea are required for marine reserves as target species often move large distances
30
Q
What is ex situ conservation?
A
- removal of organisms from their natural habitat
31
Q
What are botanic gardens?
A
- here, species are actively managed to provide them with the nest resources to grow (soil nutrients, sufficient watering, removal/prevention of pests
- 35000 plant species are conserved in botanic gardens
- but majority are still not conserved
- many wild relatives of selectively bred crop species are under represented
- wild species are a potential source of genes (resistance to pests)
32
Q
What are seed banks?
A
- example for gene bank where genetic material of plants are stored
- dried and stored at low temps (slow down rate of germination)
- many tropical seeds can be stored this way
- seed banks do not work for tropical rainforests
33
Q
What are captive breeding programmes?
A
- produce offspring of species in a human-controlled environment
- run and managed by zoos/aquatic centres
- scientists aim to create a healthy, stable population of species and reintroduce them back into its natural habitat
- provide shelter, food, absence of predators and veterinary care
- suitable breeding partners can be imported from other zoos
- maintaining genetic biodiversity can be difficult as very few breeding partners are available
- mating can be arranged to ensure maximum genetic diversity
- artificial insemination and embryo transfer allow for new genetic lines to be introduced
34
Q
What are the conservation agreements?
A
- local and international cooperation is required for the preservation of habitats and species
- IUCN (International Union for the Conservation of Nature)
- assist in securing agreements between nations
- publish red list that details the current conservation status of threatened animals
- countries work together to conserve these species
- CITES (Convention on International Trade in Endangered Species):
- regulates international trade of wild plant and animal specimens
- as trade crosses borders, the effort to regulate it requires internal cooperation
- Rio Convention:
- CBD requires countries to develop national strategies for sustainable development
- UNFCCC is an agreement where nations help to stabilise greenhouse gas conc. within the atmosphere
- UNCCD prevents the transformation of fertile land into desert (reduces the effect of drought)
- Countryside Stewardship Scheme:
- offered payments to farmers to enhance the English landscape
- sustaining beauty and diversity of the landscape
- improving, extending and creating wildlife habitats
- restoring neglected land and conserving archaeological and historic features
- improving opportunities for countryside enjoyment
- (replaced by Environmental Stewardship Scheme)
35
Q
How do humans affect biodiversity?
A
- negative impact = monoculture, deforestation
- positive impact = human intervention, management of land
- sheep grazing (enables rare species to survive)
- caterpillars feed on the low grass and this maintains their biodiversity
36
Q
Why may captive breeding not be suitable?
A
-diseases
- loss of resistance to local diseases (or a new disease may develop in the wild)
- behaviour
- some behaviour is innate but much is learnt through copying/experience
- e.g. learning to find food themselves
- genetic races
- genetic make-up of captive animals can become so different from the original pop. that they cannot interbreed
- habitat
- natural habitat must be restored to allow for captive populations to be reintroduced
- introduction of new individuals can cause stress and tension due to competition
