Biodiversity Flashcards
what do rainforests provide?
- medicine
- food and products
- their own rainfall
what is biodiversity?
the variety of living organisms present in an area
what is habitat biodiversity?
the number of different habitats found within an area
what is species richness?
the number of different species living in a particular area
what is species evenness?
a comparison of the numbers of individuals of each species living in a community
what is genetic biodiversity?
the variety of genes within a species- many of these will be the same so it becomes the variety of alleles in a population
why do we measure biodiversity?
- important role in conservation
- informs scientists of the species that are present
- provides a baseline for the level of biodiversity in an area
- allows the effects, if any, to the environment to be measured
when is an environmental impact assessment taken?
before a major project
what does the EIA attempt to predict?
the positive and negative effects of a project on the biodiversity of an area
what does the EIA look for?
- gains/loses in variety of species
- gains/loses in space available for ecosystems and habitats
- gains/loses in physical connectiveness between ecosystems and habitats
- environmental changes within ecosystems and habitats
Suggest why the habitat biodiversity would be greater in the Amazon rainforest than the Sahara desert?
There is more food and shelter in the rainforest and has a less harsh environment than the desert
Explain why intensive farming has reduced the habitat diversity of the UK countryside?
- cutting down bushes to increase size of farms
- insects and birds home gone - pesticides and insecticides
What is sampling?
Taking measurements of a limited number of individual organisms present in a particular area
What is sampling used for?
To measure biodiversity of a habitat
What is random sampling?
Selecting individuals by chance
How can you make your sampling random?
Use a grid and generate random numbers
When is random sampling used?
Used if the area looks uniform or the distribution is patchy
Why is random sampling used?
- It removes bias
- ensures sample is representative
What is non random sampling?
An alternative sampling method where the sample is not chosen at random
What are the three ways non random sampling can be carried out?
- opportunistic
- stratified
- systematic
What is opportunistic sampling?
- weakest form of sampling as it may not be representative of the population
- uses organisms that are conveniently available
What is stratified sampling?
- some populations can be divided into strata (sub groups) based on a particular characteristic
- a random sample is then taken from each of these strata proportional to its size
What is systematic sampling?
- different areas within a habitat are identified and sampled
What are the types of transects
Line of belt
What are the types of belt transects?
Continuous or interrupted
Why may a sample not be representative of organisms present in a habitat?
- sampling bias
- selection process may be biased
- reduced by random sampling - chance
- organisms selected may not be representative
- minimised by using a larger sample
Describe how a pooter can be used to collect small insects
The tube sucks small bugs into the jar
When would a sweep net be useful?
To catch flying insects that live in long grass
Explain how a pitfall trap works
There is a small pit in the ground that small bugs fall in to. They have a lid to prevent flooding
Explain how tree beating can be used to collect invertebrates
Beating a tree releases bugs from it which fall into the net underneath
Explain how kick sampling can be used to study organisms living in a river
Kicking river bed releases organisms which get caught in the net further down
What is the definition of niche?
The role of an organism within an ecosystem, the effects it has on other components of the ecosystem and the effects they have on it
What is the definition of habitat?
The part of an ecosystem where a particular organisms lives
What is an ecosystem?
The interactions between all organisms and their environment in a particular area
What is the definition of abiotic factors?
The non living physical and chemical factors in an ecosystem that affect a populations distribution and abundance
What is population?
A group of organisms of the same species living in the same place at the same time who can interbreed
What is the definition of biotic factors?
An environmental factor caused by other living organisms that effect a populations distribution and abundance
What is biodiversity?
The variety of habitats, communities and species in an area and the genetic diversity within populations. It included diversity within a species, between species and of ecosystems
What is a community?
The sum total of all living organisms of all species living in the same place at the same time
What is a species?
A group of organisms that are able to breed together to make fertile offspring and have the same morphology, anatomy, physiology and behaviour
What is species richness?
The number of species present in a habitat
What is species evenness?
The comparison of the numbers of individuals of each species living in a community
What is the equation for measuring diversity index and what do the symbols mean?
1- (n/N) 2^ n= number of individuals for each species living
N = total number of all individuals
What is the scale of diverse habitats and what do the numbers mean?
Scale of 0-1
High value = more diverse habitats, more stable and can withstand a lot of change therefore high species evenness and richness
What are genetic bottlenecks?
When a population initially has lots of alleles but an event occurs that reduces the number of individuals in the population
What can genetic bottlenecks result in?
A reduction in the gene pool as only some alleles available to be passed on
What are some effects of low genetic diversity?
- means populations cannot adapt well to environmental changes and have trouble recovering from disease
- may result in extinction
What is the founder effect?
When a few individuals from a population move to a new location
What is genetic drift?
Random as to which alleles are passed down therefore frequency of allele occurrence varies
What can genetic drift lead to?
Allele disappearing from a population
What is used to measure genetic biodiversity?
Polymorphism
What does it mean for a population when there is a greater proportion of polymorphic gene loci?
There is a greater biodiversity of the population
What is the equation for the proportion of polymorphic gene loci?
Number of polymorphic gene loci/ total number of loci
What is polymorphism?
genes that have more than one allele
What happens during gel electrophoresis?
- dna is fragmented with restriction enzymes
- it is run through a gel
- smaller segments move faster and further than large segments
What creates genetic biodiversity within a species?
Differences in alleles among individuals of a species
Why is it beneficial for a species to be more genetically diverse?
They are more likely to be able to adapt to changes in their environment and so are less likely to become extinct
What needs to occur for genetic biodiversity to increase?
The number of possible alleles in a population must increase
What is the definition of mutation?
Changes to the base sequence in the DNA
What is gene flow?
When a individual migrates from one population and breeds with a member of another population, alleles are transferred between the two populations
What is an allele?
Different versions of the same gene
What needs to occur for genetic biodiversity to decrease?
The number of possible alleles in a population must also decrease
How does artificial cloning redux genetic biodiversity?
They are clones so there is no genetic biodiversity
How does natural selection reduce genetic biodiversity?
Only selecting advantageous alleles
What is a loci?
The position of gene on the chromosome
