Chapter 11 Biodiversity Flashcards
Define Biodiversity
The variety of species, genes, and habitats in an area
Why is high biodiversity important?
All species interconnected, e.g acting as habitats, food sources, changes in one species in low biodiversity causes large consequences
We rely on balanced ecosystems for resources such as oxygen, food and medicines
What are the types of biodiversity?
Habitat- the number of different habitats present in an area
Species- species richness and species evenness
Genetic- variety of genes that make up a species
What is species richness and species evenness?
Richness- the number of different species living in an area
Evenness- the number of individuals of each species being similar
What is sampling and what is it used for?
Taking a measurement of a limited number of individual organisms present in an area
Used to estimate abundance of organisms, measure a particular characteristic
What are examples of sampling?
Random- selecting individuals by chance, mark out a grid and use a random number generator for points
Stratified- divide into subgroups and choose a representative amount for each subgroup, with those members chosen randomly
Non Random including:
Opportunistic- conveniently available for us
Systematic- transect line, samples at specified points. Or a belt, sample spaces in between
Why are samples not always reliable?
Sampling Bias- selection based, we could be biased to choose something interesting, reduced by random
Chance- not all samples representative
What techniques are used to sample animals?
Pooter- small insects by sucking mouthpiece
Sweepnets- insects in long grass
Pitfall- small crawling invertebrates like slides, spiders in ground, cover to prevent water in
Tree Bearing- invertebrates in trees
Kick sampling- organisms in rivers, kick and sweep
How are plants sampled?
Point Quadrats- metal bar where pins can be placed in, which ever plants the pin touches, are part of the sample
Frame Quadrats- frame divided into a grid
What are the three ways frame quadrats can be used to determine abundance?
Density- count the number of organisms per Quadrats, = frequency density/ square metre
Frequency- count how many mini squares the species is in, this proportion can be scaled up for whole area, useful for grass
Percentage- by eye see the percentage a species covers in a Quadrats
How do you estimate plant and animal size?
Density from Quadrat multiplied by number of quadrats needs in an area
Density + TotalSA/QuadratSA
Animals- capture recapture (number tagged originally x total number caught second time)/ number of organisms marked caught second time
What are abiotic factors and give examples?
Non-living conditions in a habitat which have a direct effect on organisms
e.g Windspeed, Light Intensity, Humidity, pH, temperature, Oxygen, Water
More helpful to be detected by sensors has human error, help identify rapid changes, increases precisions and can store data
What is the formula for Simpson’s Index of Diversity?
D= 1 - the sum of (n/N)2
Where n= number of organisms of a species
And N= the total number of organisms of all species
The larger the value, the greater the biodiversity
What are the main characteristics of a high biodiversity environment?
An unstressful environment
Less specific adaptations
Complex food webs
Not effected greatly by change
A large number of successful species
Why is a high genetic diversity important?
Important when there is a change in the environment
A larger number of alleles means there are likely to be some organisms which have advantageous characteristics when faced with a change
What factors affect genetic biodiversity?
Mutations to produce new alleles
Selective and Captive breeding, artificial cloning
Natural selection
Gene flow, Genetic Bottlenecks, and Genetic Drift
Founder effect
What is gene flow? What are genetic bottlenecks?
Gene Flow- alleles transferred between two populations
Genetic Bottlenecks- a change in the environments reduces gene pool, fewer alleles present as only those with advantageous have survived. Reduced g.b as all members of population fro ma few original survivors
What is genetic drift?
Due to the random nature of passing alleles, alleles may disappear from a population, particularly impactful when a population size is small.
What is the founder effect?
When a new population is formed due to isolation of a few members of a species, the genotype and gene pool of these few organisms will have define the genotype of the next generations
Means alleles which may have been less frequent in the old population maybe vary in allele frequency of the new population, if one of the founders has that rare allele
How can you measure the genetic biodiversity of a population?
Through polymorphic genes- when there exists multiple alleles for a gene
Proportion of polymorphic= n.of polymorphic/ total number of genes
Larger proportion, greater genetic biodiversity
How has deforestation and agriculture reduced biodiversity?
Deforestation- removing large forests for wood and space
Lower number of trees, less habitats. If a specific type of tree chosen, also reduces biodiversity
Agriculture- more farming of one plant species to maximise profit
Remove hedgerows which are a habitat, pesticides and herbicides also decrease species, which remove others food source
Think about the levels of biodiversity- species, habitat, and genetic
How does monoculture reduce biodiversity?
Only one species planted - few animals species as less habitats
Mineral depletion
How does climate change reduce biodiversity ?
Increasing global temperatures, sea levels
Decreasing glaciers and snow cover, increased precipitation
Extinctions of arctic animals
Flooding reducing habitats, also mixing salt and fresh water
Unhealthy advantage to xerophytes, dominate ecosystem
Insect populations changing
What are aesthetic reasons to maintain biodiversity?
Enriches our lives with beaches, woodlands, parks
Help reduce recovery times for patients when in nature
What are economic reasons for maintaining biodiversity?
Soil erosion and desertification will reduce the ability to grow crops, maintaining biodiversity reduces this
Crops may go extinct if not maintained. Monocultures deplete soil of minerals so farmers increasingly reliant on fertilisers, herbicides, pesticides
Non sustainable produces will eventually cause industry to collapse as they will run out, so we are trying to reduce this
Some organisms go extinct before finding a commercial use e.g medicines
Tourism
Wild plants provide genes for cross breeding to introduce desirable qualities e.g disease resistance, increased yield
What are ecological reasons to maintain biodiversity?
Removal of keystone species, small numbers but very large impact, means ecosystem destroyed
Rely on organisms, e.g pollinators
And wild plants produce gene pool that can be used to introduce desirable characteristics into commercial plants, cross breeding
What is conservation and what are the aims of it?
Human action and careful management of the environment and natural resources
Increased chance of survival, increase genetic diversity in species,
What are the two types of conversation?
In situ- in natural habitat, so maintains genetic biodiversity, evolutionary adaptations and interdependence
Ex situ- out side of natural habitat, more drastic
What do extinct, extinct in the wild, endangered, and vulnerable mean?
Extinct- organism not found anywhere
Extinct in the wild- only found in captivity
Endangered- in danger of extinction
Vulnerable- species likely to become endangered
What is sustainable development?
Economic development that meet the needs of people today, without limiting the ability of future generations
How do wildlife reserves help endangered animals?
Controlled grazing- time restrictions to allow species to recover
Restricting human access, reducing poaching
Removing invasive species, reintroducing helpful species, feeding the animals
Halting succession- the process of an early colonising species being released by a more stable species
How do botanical gardens and seed banks help maintain biodiversity?
Species given resources, soil nutrients and ideal temperatures in botanical
Seed banks effectively a gene bank, storing genetic material of seeds, but some seeds die in the process, prolongs germination
What is captive breeding? What are the advantages and disadvantages of this practice?
Offspring produced in human controlled environments, with shelter and food and an absence of predators
However:
Reduces genetic biodiversity as limited members- overcome by genetic catalogues to prevent the same DNA in offspring, including artificial insemination
Cannot be released into the wild as loses behaviours such as gathering food, disease resistance
Genes may be too different to breed with outside animals
What is the IUCN, and how does it help maintain biodiversity?
International Union of Conservation of Nature
Securing agreements, and help create conventions on International Trade
How did the Rio convention help maintain biodiversity?
UNFCCC go help stabilise greenhouse gases
UNCCD to combat desertification
Countryside Scheme to pay farmers when they sustain biodiversity, including restoring land, later replaced
What is a key stone species?
A species which has a significant impact upon an ecosystem, disproportionally compared to size of the population
Lots of organisms depend on keystone species
What does CITES do?
Ban trade of endangered animals
How can you improve using a transect line to compare the species present in each area?
Use multiple transect lines, and maybe use stratified
Repeat on a several days, all at the same time
Find a way to ensure you are not spotting the same animals multiple times in one transect
Why might having small scattered populations of an endangered species increase the likelihood of extinction?
How can zoos increase the survival of a species?
Harder to find a mate, reduced gene pool, cannot cope if there are changing selection pressures
Captive breeding
Promote awareness and need for conservation
What are marine conversation zones?
Areas which preserve coral reefs
Create areas of refuge where populations can build up and repopulate adjacent areas
Reduce destruction from overfishing
How can a tullgren funnel be used?
Funnel with a beaker below
Gauze in the funnel with leaf litter and a lamp above to attract insects
Insects fall through funnel into beaker below
Why is it important to keep rare breeds of organisms alive?
To help maintain biodiversity
Genetic resource if we need to use the alleles
e.g for genetic engineering and selective breeding to promote this trait, if the trait is useful in these changed conditions
What factors may make a breed of (sheep) endangered? General things to consider
Small populations
Results in inbreeding and small gene pools
Likely genetic drift has occured
So unable to keep breed alive is an unfavourable change in environment occurs
Why is biomass sometimes used instead of counting organisms e.g for plants and fungi?
Difficult to individually identify each organism
Too time consuming
