4.2 Biodiversity Flashcards
What is the definition of biodiversity?
Variety of organisms present in one area
What is the definition of a species?
Group of organisms with very similar appearance,anatomy,physiology,biochemistry and genetics who can interbreed to produce fertile offspring
What is the definition of a community?
All the living organisms in a habitat
What are the three levels of biodiversity?
Habitats- Number of habitats in one area
Species richness
Species evenness
Genetic
What is the difference between species richness and species evenness?
Richness- Number of species in an area
Evenness- Number of each species
Why measure biodiversity?
- Important for conservation
- Before a major project
What is sampling?
- Taking measurements of a limited number of individual organisms present in an individual area
What can sampling be used for?
- Used to measure abundance
- Used to measure a particular characteristic and workout an average
- Allows for generalisations and estimates where it would be impossible to count
What is random sampling?
Selection of individuals by chance
No involvement in location decision
What examples of non random sampling are there?
Opportunistic- Uses organisms which are convenient
Stratified- Populations are divided into subgroups based on a particular characteristic
Systematic- Different areas in a habitat are identified and the sampled separately
Why is sampling never entirely representative and how is this reduced?
Sampling Bias- Selection process may be bias due to choosing particular areas- Reduced by random sampling
Chance- Organisms by chance may not be representative of whole population-reduced by large sample size
How is plant abundance estimated?
ACFOR scale
What us a point frame quadrant?
Each plant that touches a pin is recorded
What equipment can be used to sample insects and other small animals?
- Pooter- catch insects by sucking into pot
- Sweep nets- In large areas of grass
- Pitfall traps - Hole is dug which insects cannot crawl out of
- Tree beating- large white cloth is suspended underneath tree then a tree is beaten
-Kick sampling- for river organisms,kicking the river bed
How is capture-recapture conducted?
- Capture sample of animals and count (C1)
- Mark each individual
- Release and leave traps for set periods of time
- Number captured the next time (C2), Number marked (C3)
What is the equation for capture-recapture?
Total population = (C1 x C2) / C3
What is Simpsons diversity?
The measure of diversity in a habitat
Accounts for both species richness and evenness
What is the formula for calculating species richness and evenness?
D= 1- (sum of (n/N) ^2
Where:
n= number of individuals of each species
N= total number of individuals
What does a high value for simpsons diversity mean?
A diverse habitat so environmental changes will affect few species
What is the definition of genetic diversity?
Number of different alleles that exist within a species
What is the effect of a greater genetic biodiversity?
Adapt better to the environment so less likely to become extinct
What factors increase genetic diversity?
- Mutations
- Gene flow-interbreeding between different populations
How do captive breeding programmes impact genetic diversity?
Only a small number of. Individuals so variety of alleles is smaller
What is a genetic bottleneck?
Where only a few members of a species survive a catastrophic event therefore lowering the number alleles
What is the founder effect?
When a small number of individuals create a new colony as they are isolated from the original population
What is genetic drift?
WHere the random nature of gametes fusing means certain alleles may not get passed on
How can genetic diversity be measured?
Proportion of polymorphic genes
Number of polymorphic loci/total number of loci X 100
What is a polymorphic gene?
A gene that has more than one allele
What is the definition of Loci?
Position of genes/genes on a chromosome
What factors affect biodiversity?
Deforestation- Reduces animal species due to habitat and food destruction
Agriculture- clearing of land to grow/rear animals creates a monoculture
Climate change- Rising sea levels,higher temperatures and less rainfall reduces viable habitats
What are the aesthetic reasons for maintaining biodiversity?
- Enriches walks and outdoor pursuits
- Inspiration for creative outlets
- faster recovery from illness
Economic reasons for maintaining biodiversity?
- Tourism
- Protection against certain disease
- SOil erosion and desertification makes it harder to grow food
- Lack of raw material may cause industrial collapse
What are the ecological reasons for maintaining biodiversity?
- Organisms are interdependent on each other
- Keystone species going extinct may have a disproportionately large impact
Why can a genetic bottleneck lead to low biodiversity?
- Alleles are lost
- Species descended from few survivors
What is the definition of conservation?
Preservation and management of the environment/natural resources
What is the difference between in situ and ex situ?
In situ-within natural habitat, ex situ-out of natural habitat
What are the benefits of in situ conservation?
Maintains genetic diversity and ability to adapt
Preserves interdependent relationships
Cheaper
E.g. wildlife reserves
What are the benefits of ex situ?
Used with in situ
Botanical gardens,seed banks, captive programmes
How can freezing sperm or embryos can be used in the conservation of species?
Reduces chance of genetic drift and the problems and chance with insemination
What is a conservation agreement?
Between countries and nations
What is the international union for the conservation of natures goals?
Publishes conservation status of threatened species - The red list
What is CITES for?
Regulates international trade of plant/animal specimens and their products
What is the convention of biological diversity’s goals?
Strategies for sustainable development
What is the United Nations framework convention on climate change?
Agreement to stabilise greenhouse gases
What is the purpose of United Nations convention to combat desertification goals?
Prevents transformation of fertile land into desert and reducing effects of drought.
What are the goals of the countryside stewardship scheme?
- Enhance and conserve English landscape
- Improve wildlife habitats
- Restore neglected land
- Improve opportunities
