Lecture 12 Flashcards
Australia is the _____ driest continent on Earth.
second
What are the two predominant features that impact animals?
- Climate
- Physiography (“shape of land”)
The north of Australia receives ______ rainfall, while the south receives ______ rainfall.
summer; winter
An ‘arid’ climate is defined as having insufficient _____ for _______.
rain; agriculture.
How much rain does a southern area in Aus need in order to be considered ‘arid’?
<250 mm
How much rain does a northern area in Aus need in order to be considered ‘arid’?
<500 mm
What proportion of Australia is considered arid or semi-arid?
70%
Rainfall in Australia’s arid zones is _____ and __________. (10% more variation compared to other arid zones around the world.
patchy; unpredictable.
After rain in arid areas, there is rapid _____ growth, meaning that food for animals greatly ______.
plant; increases.
In arid parts of Australia, the temperature can reach up to ___ degrees during the day and reach _____ _____ at night. There is no ______ layer to trap warmth.
45; freezing point; boundary.
List 3 main features of Arid Australia’s physiography.
- vast flat areas (vast sand dunes and some low stony hills)
- limited areas of ranges (and they are very low ranges) (Pilbara and central ranges near Alice Springs).
- highly weathered landscape (low in N and P)
Cracking soils provide _______ for _____ animals.
refuges; small.
A gibber plain is a stony desert that contains rocks high in ______ that do not _______ easily.
silica; weather
In the vast, flat parts of arid Australia there are sometimes large areas of _______ grasses such as _______. In these areas there is an _______ in biodiversity. This is because the grasses provide both a ___-________ and _____ for animals.
Hummock; Triodia; microhabitat; food.
The physical geography and climate of arid Australia leads to two main challenges for animals. What are they?
- low food and water availability for animals
- unpredictable/highly variable food and water availability for animals.
Mammals and birds are ____thermic.
endo.
Reptiles and frogs are ____thermic.
ecto.
Invertebrates (for example, ants and termites) are small, _____thermic and have ______ total energy requirements than vertebrates.
ecto; lower.
Animals in arid Australia can employ drought-______ strategies or drought-_______ strategies to deal with the challenging climate (or a combination of the two).
evasive; tolerant.
Drought-evasion strategies include:
- remaining _______ as an egg or an adult during ____ times.
- breeding _______ after rain (when water and/or food becomes available).
- _______ (e.g. budgerigars)
dormant; dry
rapidly
migration
What drought-evasion strategies do burrowing frogs such as Cyclorana employ to survive in arid Australia?
- dormant as adult
- water conservation via aestivation (lowering of metabolic rate and remaining inactivate) and cocooning (to store water)
- emerge an breed rapidly after rain
Drought-tolerant animals are often ____-lived species which tolerate very low levels of ______ and _____ due to physiological adaptations. They often have _________ strategies to assist survival.
long;
water; food
behavioural
When the air temperature exceeds the body temperature of a mammal, it will begin to employ ____________ _________.
evaporative cooling.
List 3 forms of evaporative cooling
- sweating (not usually sustainable)
- panting (primary mechanism for mammals less than 100 kg in weight)
- saliva spreading (wiped onto forelimbs and subsequent evaporation cools the animal)
