species diversity
the number of different species and the abundance of each species in an area.
genetic diversity
- the variation of alleles within a species.
species richness
- the number of different species in the area (the higher the number of species the higher the species richness)
heterozygosity index
the heterozygosity index measure the genetic diversity
h = number of heterozygotes/ number of individuals in the population
index diversity
- how to measure the species diversity
d = N(N-1)/ sum of n(n-1)
N= total number of ALL species n = total number of ONE species
- the higher the number the more diverse
niche
- the role of an organism in its habitat
echa species has its own unique niche, if two species have the same niche, one will out compete the other, then the other will die.
how organism can be adapted
- behavioural
- physiological
- anatomical
adaptations are more common.
mutations introduce new alleles into the population
selection pressures will create a struggle to survive
individuals with the advantageous allele will survive and will pass on the advantageous allele, increasing the frequency of the advantageous allele.
speciation in the devlopment of a new species
the species are geographically isolated
the conditions on each side of the barrier are different
different characteristics will be better suited for the climate
and there are different selection pressures and then those with the better allele will survive and will increase the frequency of that allele will increase
as well as mutations occuring where the advantagous mutation will survive
then they become genetically distinct, and can no longer produce fertile offspring
if any changes such as mutations occur, they can no longer
hardy weinberg
-predicts thst the frequencies of alleles in a population wont change from one generation to the next
how can biodiversity be conserved
- zoos ( captive breeding programmes)
- seed banks
conservation of biodiversity (zoos)
- captive breeding programmes involve breeding animals in controlled environments
- species that are endangered will be kept in the zoo to breed together to increase their numbers
HOWEVER…
- some people think it is cruel to keep animals in captivity
- many animals may have problems breeding outside of their homes which is hard to replicate in zoos
conservation of biodiversity (seed banks)
- store a lot of seeds from different species of plants
- help conserve biodiversity by storing the seeds of endangered plants
- if the plant is extinct in the wild the stored seeds can be used to grow new plants
- they help conserve the genetic diversity, because they have a range of seeds with different characteristics and therefore different alleles,
what is the correct environment for a seedbank
- create a cool, dry environment (when storing)
- testing the seeds for viabilities (the ability to grow into a plant)
- the seeds are planted, grown and then new seeds are harvested to put back into storage.
what are the advantages and disadvantages of seed banks
advantages
- cheaper to store seeds than plants
- large number of seeds can be stored
- less labour (less work is needed to keep the seeds)
- the seeds can be stored anywhere as long as conditions are correct
- the seeds are less likely to be damaged by disease, natural disaster, or any type of vandalism.
disadvantages
- the testing for the viability of the plants can be expensive and time consuming
- it is difficult to collect seeds from plants as they may grow in very remote areas
reintroduction into the wild (from seed banks and zoos)
- when they are reintroduced, it will increase the number in the wild, to help conserve and bring back their number
- helps organisms that rely on these plants or animals as food or as a part of their habitat
- they also contribute to restoring habitats that have been lost.
HOWEVER
- this can bring new diseases (then harm others)
- they may not behave as they should such as finding food (causing them to struggle)
how seed banks and zoos contribute to scientific research.
- seed banks can be used to grow endangered plants for use of medical research as new crops or new materials ( and we do not remove any endangered species for this research)
- however data from seed banks is small interbred population so the information is not representative of wild plants
- research in zoos increase knowledge about the behaviour, physiology and nutritional needs of animals (which can be used to help conserve that animals better)
- they can carry out research that is not possible in the wild
HOWEVER the animals may act different when captive
structure of the xylem
- the role of the xylem is to transport the water and mineral ions and is also needed for structure
- they are long hollow tubes formed from dead cells, joined end to end.
- they have no end walls, this is for the uninterrupted transport of water ( to the cohesion tension model of water. water is cohesive because it will firm hydrogen bonds with other water molecules and due to the tension each water molecule is pulled up and then evaporates at the leaf, therefore pulling it from to root to the leaf and this is continuous)
- their walls have lignin infused inside to provide support
- water and minerals move in and out of the vessels through the pits (the parts of the wall with no lignin)
structure of the sclerenchyma fibres
- the sclerenchyma tissue is used to provide support (but not transport)
- they are made of dead cell that run up the stem
- long, wide, hollow lumen with end walls
- thickened with lignin and made of cellulose
structure of the phloem
- used for the transport of organic solutes (translocation)
- it is only used for transport not strcuture
- has sieve tube elements which are living cells which are joined end to end to form sieve tubes
- the end of these tubes have holes so solute can pass through
- the sieve cells have no nucleus and not a lot of organelles so it cannot survive on its own ( so it has a companion cell which carries out all the reactions for both of the cells).
structure of cellulose
- cellulose is a made of long unbranched chains of beta glucose joined by 1,4 glycosidic bonds
- due to the bonding the cellulose chains are straight
- between 50 and 80 cellulose chains are linked together by hydrogen bonds
- this makes MICROFIBRILS which allows it to provide structural support
practical for tensile strength
- attach the fibres to a clamp stand and hang a weight from the other end
- keep adding weights one at a time until the fibre breaks
- record the mass needed to break the fibre
- repeat the experiment making sure that all the fibres are the same length and then get the mean.
ions needed for plants.
- magnesium is needed for CHLOROPHYLL
- nitrate is needed for synthesis of DNA and PROTEINS
- calcium ions needed for the cell wall
practical for mineral deficiency
- use a pestle and mortar , create a pine needle extract
- place paper disk of the same diameter into the extract (allow the ethanol to evapouate)
- then aseptically transfer to nutrient agar plate that has been previously innoculated in e coli ( need to spread bacteria over agar so we can investigate the antibacterial properties of bacteria)
- then incubate in 25 degrees for 2 days
- examine the plates for zones of inhibition (the bigger the better)
- use sterile water as a control
- work near a busen burner to create a convection current
