biodiversity

ecosystems

self-contained community of interacting organisms and the environment they live in

population

group of individuals of the same species living in the same area or habitat

species

a group of similar organisms that can reproduce to give fertile offspring

species richness

the number of different species present

species evenness

• the number within each species present within a habitat

• habitats with species of similar abundance will have a greater species evenness

systematic sampling

• samples are taken at fixed intervals

• quadrats are placed along the transect (continuous line transect)

opportunistic sampling

• the samples are chosen by the investigator

• simple but not representative

• potential for bias as not randomly selected

stratified sampling

• different areas of a habitat are identified and are sampled separately in proportion to their part of the habitat

• the number of samples taken are directly proportional to the size of area

random sampling

• map out the total area

• divide the area into a grid, using measuring tapes

• utilise a random number generator to generate coordinates

• place the quadrat on those coordinates

low species evenness

• one or few species dominate the population- outnumbering the other species

• low abundance

• these ecosystems can be more vulnerable to selection pressures e.g disease, climate

genetic diversity

• diversity of alleles and genes in the genome of species

• limited in populations that are very small or isolated e.g inbreeding leads to a higher proportion of homozygous- reduces genetic diversity

gene pool

all the alleles of all the genes within a species

genetic diversity within species

creates a larger gene pool which helps the population to adapt and survive abiotic/biotic changes

allele richness

the number of different alleles that exist for specific genes

proportion of polymorphic gene loci

the number of loci that have two or more alleles

genetic polymorphism

occurs when there are two or more alleles present at a single loci

polymorphic locus

locus that has multiple alleles

limitation of using the P equation

it doesn’t illustrate the allele richness of a breed or species

habitat fragmentation

• habitat is divided into smaller areas usually due to deforestation, agriculture etc

• populations are more likely to suffer from inbreeding or local extinction

over exploitation

• harvesting a species faster than it can naturally replenish

• leads to the depletion of fish stocks, timber etc

pesticide effects on biodiversity

they kill many non-target species that are essential to ecosystems e.g bees

fertilizer effect on biodiversity

• they leach into waterways- eutrophication

• this can cause algal blooms, block sunlight, deplete oxygen etc

hedgerows effect on biodiversity

removal of hedgerows destroys habitat for biodiversity e.g insects, birds etc

global warming effect on biodiversity

it’s causing some species to move to the poles or to higher altitudes- they won’t be able to compete with the present species so leads to lower biodiversity

increasing atmospheric CO2 effect on biodiversity

• it’s causing more CO2 to dissolve in sea water, which lowers the pH- ocean acidification

• this negatively impacts organisms that require calcium carbonate for shells

moral and ethical reasons for maintaining biodiversity

humans have a responsibility and duty to reduce their impact on the planet and other species

ecological reason for maintaining biodiversity

biodiversity increases the stability of ecosystems

environmental reason for maintaining biodiversity

organisms provide essential environmental services e.g water cycle, nutrient cycle, absorption of CO2

economic reason for maintaining biodiversity

a range of organisms contribute to medicine, ecotourism and science + technology etc

aesthetic reason for maintaining biodiversity

humans take pleasure in visual effects of biodiversity

agricultural reason for maintaining biodiversity

genetically diverse wild species can rescue crops from catastrophes

national parks (method of maintaining biodiversity)

• protecting endangered animal + plant species through strict regulations

• increasing public engagement in conservation

marine parks (method of maintaining biodiversity)

protecting endangered marine species through restrictions e.g over fishing, pollution etc

zoos (method of maintaining biodiversity)

captive breeding programs for the re-introduction of animal species into the wild

botanic gardens (method of maintaining biodiversity)

captive breeding programs for the reintroduction of plant species into the wild

frozen zoos (method of maintaining biodiversity)

long term storage of animal genetic material at very low temperatures

seed banks (method of maintaining biodiversity)

long term storage of plant genetic material in a temperature-controlled environment

International Union for Conservation of Nature (IUCN)

assesses the conservation status of animal and plant species around the world, classifying them by their risk of extinction

Convention on International Trade in Endangered Species wild flora and fauna (CITES)

• aims to control the trade of endangered species and their associated products e.g elephants and their ivory tusks

• Appendix 1- prohibiting commercial trade for highly endangered species e.g red pandas

• Appendix 2- allowing commercial trade only with permits

phylogeny

the evolutionary relationship between the history of species

biodiversity

• combination of species richness and species evenness

• range or variety of allele, genes

• variety of species in an area