The Vulnerable Australian Environment Part 2-Lesson 1
Slide 2
The Physical Nature of the Australian Environment Not only is
Australia the oldest continent on Earth (4.1byo), its also the
flattest and lowest. Australia is the only continent to not have
any permanent areas of snow and ice.
Slide 3
The Physical Nature of the Australian Environment There has
been very little geological activity in recent times which has
resulted in several hundred million years of erosion. This is why
Australia is a broad, flat, geologically stable continent.
Slide 4
The Physical Nature of the Australian Environment The soils of
Australia are also very old. Most of the nutrient have been leached
out leaving them poor and unable to support life. Do you remember
where the only reasonably fertile soils is located in our country
and why?
Slide 5
The Physical Nature of the Australian Environment Australia is
the second driest continent in the world. Do you know the driest?
This is because of our relative position to the equator and low
relief. 1/3 of our country is classified as arid with an average
rainfall of less tan 250mm per year.
Slide 6
The Physical Nature of the Australian Environment Some areas
may go years with little rain and then get 6 months worth in one
week. Australias climate is also closely related to El Nino, which
occurs irregularly over 2 to 6 years. During these periods
Australia receives less rainfall and higher temperatures than usual
resulting in droughts and more bushfires.
Slide 7
The Physical Nature of the Australian Environment Fires are
very common in Australia and are a major environmental force. The
generally warm, dry weather combined with the flammable nature of
most of the common native plants, means bush fires are a part of
life.
Slide 8
The Physical Nature of the Australian Environment Scientists
have analysed sediment cores from old lakes and they indicate that
there has been a dramatic increase in bushfire frequency in the
last 60,000 years. Why might this be true? Arrival of Indigenous
People (fire) and extinction of megafauna (more plants/fuel for
fires)
Slide 9
The Biological Nature of the Australian Environment The flora
and fauna of Australia is very diverse and distinct. Much of it is
said to be endemic, which means native to a particular location.
This is because Australia has been geographically isolated for
millions of years which has prohibited plants and animals from
moving and bringing about constant change.
Slide 10
The Biological Nature of the Australian Environment Australias
flora is dominated by 2 genera of plants: Eucalypts (gums) and
Acacia (wattles). There are 500 species of Eucalypts in the world
which most are endemic to Australia.
Slide 11
The Biological Nature of the Australian Environment Acacia also
grow in Africa, India and South America, which were all once
connected as part of Gondwana. of the 1200 species are found in
Australia.
Slide 12
The Biological Nature of the Australian Environment Most of
Australia's native plants have adapted to low rainfall and
infertile soils. For example, sclerophylls has hard, leathery
leaves designed to reduce water loss. Xerophytes have small spiny
leaves,
Slide 13
The Biological Nature of the Australian Environment Many native
plants also contain oils and other chemicals as defence against
herbivores and have extensive root systems, an inverted umbrella
design to catch water and low growth rates. How might these
characteristics help native plants survive?
Slide 14
The Biological Nature of the Australian Environment Australias
fauna is also unique and dominated by marsupials. This group, along
with monotremes was once wide spread in other Gondwana
continents.
Slide 15
The Biological Nature of the Australian Environment Our birds,
reptiles and amphibians are also very diverse and unique. Most are
specifically adapted to the conditions of our continent.
Slide 16
The Biological Nature of the Australian Environment Because the
waters around Australia are low in nutrients, our native aquatic
fauna is small compared to other continents. For example we only
have about 200 native species as opposed to North America who has
760. Why do you think our waters are low in nutrients?
Slide 17
Abioic and Biotic Features of the Environment Abiotic are
non-living and Biotic are living features of an environment or
ecosystem and affect an organisms chance of survival.
Slide 18
Abioic and Biotic Features of the Environment Biotic Features:
Number of the same species of plant/animal available as mates
Number of competators for the same resources, such as light, food
and shelter Number of predators Seasonal availability and abundance
of food Disease causing orgasnisms
Slide 19
Abioic and Biotic Features of the Environment Abiotic Features:
Availability of water Availability of nutrients Availability of
light Soil type/texture Temperature range Availability of space and
shelter Air movements Soil pH Altitude and topography
Slide 20
Abioic and Biotic Features of the Environment Abiotic Features
for aquatic environments: Levels of dissolved oxygen Rate of water
movements Water pH Water turbidity Water pressure and depth
Viscosity Types of substrates (mud, sand and rock) Salinity
Slide 21
Review The flora and fauna of Australia is very diverse and
distinct. Much of it is said to be endemic, which means native to a
particular location Australias flora is dominated by 2 genera of
plants: Eucalypts (gums) and Acacia (wattles). There are 500
species of Eucalypts in the world which most are endemic to
Australia. Australias fauna is also unique and dominated by
marsupials. The history of our flora and fauna species goes back to
Gondwana
Slide 22
Homework Read pages 189-192 HSC Spotlight Text Update
electronic vocabulary Complete DOT Point 2.1 pg 93
Slide 23
The Vulnerable Australian Environment Part 2-Lesson 2
Slide 24
Effects of Introduced Species Activity Read pages 192-193
together Complete Activity 4.7 together
Slide 25
Homework Update electronic Vocabulary Complete To Think About
pg 195-196 HSC Spotlight Text Complete DOT Point 2.2
