Biology- Biodiversity Flashcards
What is the importance of biodiversity
maintains and balanced ecosystem as all species are interconnected to one another
why is maintaining biodiversity important
important in conservation, informs scientists of the species that are present, its the baseline for species in that area
what causes the effects of changes in environment
human activity
disease
climate change
what are the different levels of biodiversity
- habitat biodiversity
- species biodiversity
- genetic biodiversity
what is habitat biodiversity
number of habitats found within the area, each habitat can support different species, the greater the habitat the greater the biodiversity within that area
what are the two species biodiversity
species richness
species evenness
what is species richness
the number of different species living in a particular area
what is species evenness
comparison of numbers of individuals of each species living in a community
what is genetic biodiversity
variety of genes that make up different species, many genes are the same for all individuals within a species , however many genes have different versions (alleles that exist) - leads to genetic biodiversity
what can genetic biodiversity lead to?
can lead to different characteristics within a species, it allows for better adaptation to a changing environment, make some individuals resistant to disease
what is sampling
taking measurements of a number of individual organisms present in a particular area
what is sampling useful for
its an estimate of the number of organisms in an area without having to count them all
can also be used to measure a particular characteristic of an organism
what is random sampling
selecting individuals by chance, equal likelihood for selection
how to carry out a random sample 3 steps
1- mark out a grid on the grass using two tape measures laid at right angles
2-use random numbers to determine the x coordinate and the y coordinate
3- take a sample at each of the coordinate pairs generated
what is non-random sampling
alternate sampling method where the sample is not chosen at random, can be divided into 3 techniques
what are the 3 techniques of non-random sampling
- opportunistic
- stratified
- systematic
what is opportunistic sampling
Uses organisms that are available there
-weakest form of sampling, doesn’t represent whole population.
what is stratified sampling
population divided into a number of different strara (subgroups) based on a characteristic
A random sample is taken from each of these strata.
what is systematic sampling
different areas within a overall habitat are sampled separately. Carried out on a line or belt transect
what is a line transect
making a line along the ground between two poles and taking samples at specific points
what is a belt transect
two parallel lines are marked, samples are taken from the area between the two lines
-provides more information
what is a sampling bias (reliability)
selection process may be biased, way to stop this is using no human involvement when choosing a sample area
what is chance (reliability)
organisms may be selected by chance, not represented by the whole population. To reduce is can use a large sample size
Example 1: sampling animals
Pooter
catch small insects by sucking on a mouthpiece, insects drawn into the chamber via inlet tube. Filter stops the insect going into the mouth
Example 2: tree beating
used to take samples of invertebrates living in a tree or a bush. Large white cloth underneath the tree. Large white cloth stretched out under the tree .Tree is shaken so invertebrates fall out to be collected or studied
how are plants usually sampled
using a quadrat, to pinpoint an area for the plants to be collected
what are the two types of quadrats
point quadrat
frame quadrat
point quadrat
frame with horizontal bar. Set intervals along the bar, long pins can be pushed through the bar to reach the ground. Each species that touches the pin is recorded
frame quadrat
consists of a square frame divided into a grid of equal sections. Type, number of species within each section is recorded
three types of sampling population (using a quadrat) of plants living in a habitat
- density
- frequency
- percentage cover
density
if plants can be seen clearly, count number of them in 1m by 1m square. Give density per square meter not an estimate
frequency
if individual members of species are hard to count. Using a small grid within a quadrat, count number of squares species is in.
percentage cover
used to gather data fast, if species is abundant or hard to count. Estimate by eye of area of area within a area within a quadrat
how to estimate animal population size
capture-mark-release-recapture, capturing as many organisms in the area as possible. Then marked and then released back to the community. Time allowed for them to redistribute themselves before another sample is collected. Compare number of marked/unmarked organisms can estimate population size
what is abiotic
non-living conditions in a habitat,have a direct effect on living organisms.
examples of abiotic factors
wind speed light humidity pH temperature
abiotic factors can be measured with sensors, how are they useful?
- Detect rapid changes
- Reduce human errors when reading numbers
- High accuracy
what is the simpsons index theory
measure of biodiversity as it takes into account both species richness and species evenness
how do you know if a habitat has high or low biodiversity according to the simpsons scale?
the closer the value is to 1 the more diverse the habitat is
characteristics of a high diversity environment
-great number of successful species- more stable ecosystem
Environment isn’t hostile, more relaxed
Complex food webs
environmental change will be damaging to ecosystem as a whole
characteristics of low species diversity environment
fewer successful species in the environment
Environment is stressful, fewer organisms adapted to that environment
simple food webs
what needs to happen in order for genetic biodiversity to increase?
number of possible alleles in a population must increase
factors that enable the population to increase
1- mutation
mutations in the DNA, creating new allele
factors that enable the population to increase
2-interbreeding
interbreeding between different populations. Individual migrates from one population and breeds with another. Alleles transferred between two populations-known as gene flow
what happens if genetic biodiversity decreases
number of possible alleles in a population must also decrease
what can the decrease of genetic biodiversity occur through? 1-selective breeding
selective breeding, few selected for advantageous characteristics and bred
captive breeding?
zoos and conservation centres, small number animals available for breeding.
natural selection?
species will evolve to contain alleles which encode for advantageous characteristics. Over time less advantageous characteristics will be lost from the population
genetic bottle necks?
few individuals within population survive an event/change, reducing gene pool. Only alleles of surviving population pass offspring
the founder effect
small number of individuals create a new colony, geographically isolated from the original. Gene pool is small
how to measure genetic biodiversity?
measuring polymorphism
what are polymorphic genes
genes that have more than one allele
what are monomorphic genes
gene only has 1 allele
formula for polymorphic gene loci
proportion of polymorphic gene loci= number of polymorphic gene loci (divided) by the total number of loci
what does locus mean
position of the gene on a chromosome
3 factors affecting biodiversity
- deforestation
- agriculture
- climate change
what is deforestation
permanent removal of trees to provide wood for building or fuel/ create space for roads, building and agriculture
what is agriculture
More land needs to be cleared to feed the growing population. Then they plant a single crop (monoculture)
what is climate change
release of co2 and pollutants from burning fossil fuels increases temperatures
how does deforestation affect biodiversity
- reduces number of trees in area
- species diversity reduced
- animals forced to migrate to other areas to survive. Might increase the biodiversity in other regions
How does the use of pesticides reduce biodiversity in the area
Pesticides kill pests that would eat the crops. Reduces species diversity as it kills off pests (insects) and destroying food source for other organisms
How do herbicides reduce biodiversity
used to kill weeds, plants diversity is reduced, removal of important food sources
how does monoculture reduce biodiversity
farms specialise production of only one crop, many acres of land to grow one type of species. Lowers biodiversity, animal species will only have one type of food source.
How will biodiversity be affected by climate change?
- melting of polar icecaps can lead to extinction of plants and animal species. Animals forced to migrate north to new conditions that suit them.
- rising sea levels from melting icecaps and thermal expansion of oceans could flood areas/habitats
- higher temperatures and less rainfall would affect plant species making xerophytes more dominant, food source is also reduced for animals that feed on them
3 reasons for maintaining biodiversity
- aesthetic
- economic
- ecological
what is the aesthetic reason for maintaining biodiversity
- presence of plants and natural habitats are calming/therapeutic for people
- heals people
- provides inspiration for people
what is the economic reason for maintaining biodiversity
- soil erosion and desertification man occur because of deforestation. Reduce countries ability to grow crops and feed people can lead to resource and economic dependence on other countries
- deforestation can lead to extinction of plant species that can be medically /chemically useful.
- areas with biodiversity are attractive can attract tourism to the area which will increase economy
- continuous monoculture results in soil depletion-reduction of diversity of soil nutrients. Happens because crop is using same soil year after year-makes ecosystem more fragile Crops will be weaker so more expensive pesticides need to be used
what is a ecological reason for maintaining biodiversity
- organisms are dependent on each other for survival, removal of one species may have a significant affect of another. For e.g food source may be lost
- some species may play a key role in structure of the community (ketone species). Large effect on the environment. Determine species evenness and richness. when they are removed habitat is drastically changed
what is a keystone species
species that are important in maintaining the structure of a ecological community. Large effect on the environment.
what is conservation
preservation and careful management of the environment. organisms chance of survival are maintained allowing them to reproduce
2 ways of conserving biodiversity
- in situ
- ex situ
what is in situ conservation
within natural habitat
maintains their genetic diversity and evolutionary adaptations, can continually adapt to environmental changes as they’re still living within their habitat.
-cheaper than ex situ conservation
what is ex situ conservation
out of natural habitat
how do botanic gardens help with maintaining biodiversity
plant species can be grown, they’re managed and given resources to grow (soil nutrients , sufficient watering)
how do seed banks help with maintaining biodiversity
example of a gene bank, store of genetic material. Stored so that new plants can be grown in the future. they are dried and stored at low temperature so they slow down the chance to germinate. Provide a backup against extinction of plants.
how do captive breeding programmes help maintain biodiversity
produce offspring of species in human controlled environments. Managed by zoos, aquatic centres. create a stable, healthy population of species and then slowly reintroduce them back into the environment.
create stable shelter , abundant supply of food and absence of predators.
how can maintaining genetic diversity within a breeding problem be difficult? how can we overcome this?
only small number of breeding partners available, problems with interbreeding can occur. to overcome this international catalogue is maintained. artificial insemination can also occur
