Part 2-Lesson 1

The Vulnerable Australian EnvironmentPart 2-Lesson 1The Physical Nature of the Australian EnvironmentNot 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.

The Physical Nature of the Australian EnvironmentThere 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.

The Physical Nature of the Australian EnvironmentThe 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?

The Physical Nature of the Australian EnvironmentAustralia 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.

The Physical Nature of the Australian EnvironmentSome 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.

The Physical Nature of the Australian EnvironmentFires 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.

The Physical Nature of the Australian EnvironmentScientists 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)

The Biological Nature of the Australian EnvironmentThe 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.

The Biological Nature of the Australian EnvironmentAustralias 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.

The Biological Nature of the Australian EnvironmentAcacia 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.

The Biological Nature of the Australian EnvironmentMost 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,

The Biological Nature of the Australian EnvironmentMany 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?

The Biological Nature of the Australian EnvironmentAustralias fauna is also unique and dominated by marsupials. This group, along with monotremes was once wide spread in other Gondwana continents.

The Biological Nature of the Australian EnvironmentOur birds, reptiles and amphibians are also very diverse and unique. Most are specifically adapted to the conditions of our continent.

The Biological Nature of the Australian EnvironmentBecause 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?

Abioic and Biotic Features of the EnvironmentAbiotic are non-living and Biotic are living features of an environment or ecosystem and affect an organisms chance of survival.

Abioic and Biotic Features of the EnvironmentBiotic Features:Number of the same species of plant/animal available as matesNumber of competators for the same resources, such as light, food and shelterNumber of predatorsSeasonal availability and abundance of foodDisease causing orgasnismsAbioic and Biotic Features of the EnvironmentAbiotic Features:Availability of waterAvailability of nutrientsAvailability of lightSoil type/textureTemperature rangeAvailability of space and shelterAir movementsSoil pHAltitude and topographyAbioic and Biotic Features of the EnvironmentAbiotic Features for aquatic environments:Levels of dissolved oxygenRate of water movementsWater pHWater turbidityWater pressure and depthViscosityTypes of substrates (mud, sand and rock)Salinity ReviewThe flora and fauna of Australia is very diverse and distinct. Much of it is said to be endemic, which means native to a particular locationAustralias 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

HomeworkRead pages 189-192 HSC Spotlight TextUpdate electronic vocabularyComplete DOT Point 2.1 pg 93The Vulnerable Australian Environment

Part 2-Lesson 2Effects of Introduced SpeciesActivityRead pages 192-193 together

Complete Activity 4.7 togetherHomeworkUpdate electronic VocabularyComplete To Think About pg 195-196 HSC Spotlight TextComplete DOT Point 2.2