IB biology: option C (III)

what are endemic species?

those which are native to a defined geographic region (e.g. koalas in Australia)

what are alien species?

those that have been transferred from their natural habitat to a new environment

what is an invasive species?

if an introduced alien species should have a detrimental effect upon the pre-existing food chains

examples of invasive species in Australia?

cane toad, red fox, european rabbit

what is the competitive exclusion principle?

two species cannot occupy identical niches within a community

what are advantages that invasive species may have over endemic species? (4)

possess a large fundamental niche,

faster reproduction rates,

lack a predator,

possess certain features that are suited to the new environment

what are methods of controlling populations?

physical, chemical and biological

what is physical control?

the removal or restriction of invasive species by manual or mechanical measures

what are examples of physical control? (3)

installation of barriers/fences,

removal of habitat by excavation,

hunting/trapping

what is chemical control?

the use of chemical agents (poisons and toxins) to limit population numbers and spread

what are examples of chemical control?

herbicides, pesticides, rat poision

what is biological control?

using a living organism (or a virus) to control an invasive species

what are examples of biological control?

eat invasive species (predation),

cause it to become diseased

what is biomagnification?

the process in which chemical substances become more concentrated at each trophic level

what is bioaccumulation?

the build up of a chemical substance in the tissues of a single organism

example of a chemical substance which is biomagnified?

DDT

what is DDT? what are its effects?

a chemical pesticide that is sprayed on crops for mosquito eradication,

birds exposed to high levels of DDT were found to produce thinner shells

what is the difference between macroplastics and microplastics?

macroplastics are larger than 1mm, microplastics are smaller than 1mm

how do microplastics/macroplastics travel through food chains?

macroplastic and microplastic debris is ingested by marine animals, which mistake the debris for food

what are consequences of microplastics/macroplastics?

bioaccumulation and biomagnification of persistent organic pollutants within marine animals,

damage the stomach of animals/cause them to stop feeding (by taking up space in the digestive tract)