unit one - BIOLOGY

Habitat destruction

the elimination or alteration of the conditions necessary for plants and animals to survive

urbanisation

extreme modification of an ecosystem by humans to support human population gradually increasing

fragmentation

occurs when some parts of the habitat of an ecosystem are separated into isolated sections

seed bank

reservoir for plant genetic material, especially species threatened by extinction

bush corridors

a link of wildlife habitat, which joins 2 or more larger areas of similar habitats

salinity

the concentration of salt in soil

introduced species

species that have been intentionally/unintentionally moved from their native location to a new ecological region

exotic

species living outside its native habitat

invasive species

introduced species that manage to establish population in new areas

chemical control

a chemical such as a pesticide or poison that is used to control the population of an invasive species

biological control

another species introduced that can control the population of a pest species

culling

killing and removing of individuals in population in order to remove negative impacts it is having on an ecosystem

unsustainable use

practises or actions that cannot be continued at the same rate or level without causing harm

overhavesting

the unsustainable extraction of natural resources

eutrophication

excessive richness of nutrients in a lake or body of water

biomagnification

increasing concentration of a substance like a pesticide as it moves up the food chain

climate

weather conditions in an area in general or over a period of time

weather

temperature and conditions/ state of atmosphere in an area

climate change

long term shifts in temperature and weather patterns

green house effect

trapping of suns warmth in the planets lower atmosphere/ earths surface

enhanced greenhouse effect

extra greenhouse gasses in our atmosphere trap to much of the suns energy

deforestation

process of clearing forests and replacing them with non forest land uses

habitat destruction & fragmentation - urbanisation impacts

additional resources for modern living lead to increase of output of gaseous and material water, dumped into the atmosphere

little recycling of matter

habitat destruction & fragmentation - agricultural impacts

20% of au forests cleared for crops

road kill increases

leads to fragmentation, fewer mating options

division in populations

habitat destruction & fragmentation - habitat fragmentation

isolates groups of bigger populations

when faced with conditions smaller populations are not as resilient leading to increase in population or local extinction

smaller subpopulations cannot interbreed

genetic conservation strategy- seed banks

WA seed centre

• collect, store and test native plant seeds for more than 3500 plants

• carefully maintained to be kept viable

• if species goes extinct seed bank can be used to introduce it back into habitat

environmental conservation strategy - revegetation and bush

effective way of returning habitat to populations and enabling subpopulations to breed

Godwana link, reconnect bushland in south west of Australia since 2002

management conservation - protected areas and standards

rules to protect and repair ecosystems

Carnaby’s black cockatoo

• protect habitat

• research into population dynamics

• monitor nests

Dryland salinity

process of salts normally found beneath surface of soil being transported to the soil surface by a rising water table

if concentration becomes to high plants no longer grow, infertile soil

removal of deep rooted trees make water table rise

introduced species example

cane toad

introduced as biological control to Queensland to prey on cane beetles in the sugar cane crops

toads deadly with toxic glands, species prey on the toad and die due to the poison

compete w/ native species for food

killed so many native animals → threat to AU genetic species and ecosystem diversity

chemical control of introduced species

• quick and effective way to get rid of pests

• can be ecologically damaging and costly

• land owners use bait to protect there animals from invasive species

• code of practise for baits & poison

biological control of introduced species

• exploits relationship between organisms

• integrate response with chemical control

• can easily fail like the cane toad

types of narrow spectrum agents

• general predators

• specialised predators

• parasites

• microbial diseases

microbial diseases as an agent

death through illness, fungi or bacteria

general predators as an agent

consumes a variety of pests

specialised predators as an agent

species that target one species of pest

parasites as an agent

lay egg in the host, the egg then hatches and eats the host, causing its death

example of unsustainable use of resources

Overharvesting

harvesting a species at a rate that exceeds the replenishing rate of the population

organisms low reproductive rate vulnerable to this

African elephants (tusks)

birth & immigration < death & emigration

impact of pollutants- eutophication

human impact: agricultural run off, sewage discharge

Darling river algae bloom 1991

conservation: waste water treatment, wetland restoration

impact of pollutants- biomagnification

organisms acquire toxins from environment

DDT insecticide, used to kill mosquito

presence in trophic levels lead to health problems within animals

cancer, infertility

impact of pollutants - plastics

enter water ways, trapping animals & consume it

turtles consume plastic bags thinking it is a jellyfish

intestinal blockages, pierced by sharp plastic

enhanced greenhouse effect

occurring because concentration of greenhouse gases have increased & to much heat is being retained

human activities like fossil fuel combustion have made it increase

environment management - culling

controversial

2 mil kangaroos culled per year, to manage overpopulation and overgrazing

200 mil per year industry

used for human consumption but mainly export

environment management - reintroducing populations

Galaxious- native fresh water fish

• suffered intro of mosquito fish

• reduction of galaxious led to decrease of native frog and aquatic species

• dont lay eggs, so live young are easily eaten

  to reintroduce successfully mosquito fish must be absent