Yr 11 Evolution of Australian Biota Workshop
Welcome to the Australian Biota Workshop!!
Today’s lesson is jam packed with information about
some of Australia’s most amazing animals. We will
cover lots of the Australian Biota syllabus points plus
lots of other information you will need to have a good
understanding of biology.
Some of the main points to have in mind are:
A) Humans only live a short amount of time - lots of
the processes we are studying (ie evolution) take
place over much larger timeframes
B) The world is a changing place - the continents
move, the climate changes, the plants and animals
respond to these changes continuously - its not a
one directional change!
C) Fitness - the priorities of an animal are often
different to those of a human. In biology, we
consider the ability of an animal to produce
successful offspring as the ultimate achievement.
This is known as fitness.
Basic Vocabulary/Concepts:
1) Nocturnal, Diurnal, Crepuscular
2) Bahavioural, Structural and physiological
adaptations
3) Ectothermic, endothermic
4) Arid, temperate environments
5) Camouflage
6) Arboreal
7) Vertebrate animals - Fish, Amphibians, Reptiles,
Birds and Mammals (Monotremes, Marsupials,
Placentals)
And lots more…
THE STORY SO FAR...65 MYA the
extinction of the dinosaurs made way for the
‘Age of Mammals’…
Syllabus ref. 8.5.1, Evidence for the rearrangement of crustal plates
and continental drift indicates that Australia was once part an
ancient super continent.
Syllabus ref. 8.5.1—fossils in common on Gondwanan continents,
Marsupials
Gondwana
55 million years ago
Separated Continents
20 million years ago to present
Image by Cody Pope (Virginia Opossum)
Marsupial Fossil Record
South America - oldest
fossils 70 mya
Antarctica - some teeth
and bone fossils found
Australia – oldest fossils
55 mya
Evidence for continental drift:
Monotremes
Monotreme Fossil Record
The location of known Monotreme fossils are shown:
LR - Lightning Ridge
R - Riversleigh
Steropodon - 110 mya
Obdurodon - 65 mya
Kollikodon - 110 mya
P - Patagonia
(very different teeth to later
Monotrematum - 65 mya
platypus-type animals)
(modern tooth types)
Placental Fossil Record
Fossils indicate Placental mammals
were also found in Southern
Hemisphere, though these organisms
died out early on. Successful Placental
mammals are evolving in Laurasian
continents at this time.
Illustration - Australian Museum
20 MYA to present
Musky Rat Kangaroos evolved 20MYA but
still live in remnant areas of rainforest in
Northern QLD (living fossil)
KANGAROO EVOLUTION
Features:
25 MYA.Northern Australia is still
warm and wet and covered in
rainforest. Kangaroo ancestors are
arboreal and have possum like
features
Features:
20-15 MYA Southern Australia is
dominated by savannah/open
woodland. Huge radiation of kangaroo
species in this time. The first
megafauna appear
Features:
Start:
5-3MYA
Rainforests return to large
areas of northern Australia & PNG some species of Kangaroo return to an
arboreal existence—Tree Kangaroo’s
55 Million Years Ago
Kangaroos split from last common
ancestor. Australia is covered in
rainforest and still connected to
Antarctica
Features:
Present Day
There are now over 60
species of Macropods in
Australia. Red
Kangaroo’s are one of
the most successful
species in Australia
Features:
Illustrations - Australian Geographic
Syllabus 8.5.4—gather, process and
analyse information from secondary
sources and use available evidence to
propose reasons for the evolution,
survival and extinction of species,
with reference to specific Australian
species
100 000—20 000 years ago
This is a period of rapid temperature
change and therefore rapid plant and
animal evolution. Evolution and
extinctions of many megafauna species
8 MYA
Arid areas increasing as polar
ice caps increase. Hopping
Kangaroo species dominate
the forest floor
Features:
4-2 MYA
Southern Australia experiences
larger arid areas than present due
to glaciations. The beginning of
modern kangaroo evolution. Reds
appear at 2 mya
Features:
Features:
KANGAROO EVOLUTION
Red Kangaroos are an extraordinarily successful species. Give
some reasons for their success, and describe some of their
adaptations.
Syllabus 8.5.4 - Gather, process and analyse
information from secondary sources and use
available evidence to propose reasons for the
evolution, survival and extinction of species,
with reference to specific Australian species
Red Kangaroos are a relatively new species, but have had a long evolutionary path.
Using your knowledge of the ancestral body type, provide reasons for the changes we can see to their
body shape and dentition.
It is estimated that there are 10-100 million species of living things on Earth, but that
billions of species have already become extinct. Propose reasons why some species
survive longer than others, and why some species go extinct. (Like the early placental
mammal in Australia!)
Illustrations - Australian Geographic
FERTILISATION AND SURVIVAL OF YOUNG IN AUSTRALIAN FAUNA
Saltwater Crocodile
General Notes:
What features or behaviours do Salt Water Crocodile have that help ensure
fertilisation of their eggs?
What features or behaviours do Salt Water Crocodile have that help ensure
their young survive?
Images - Australian Geographic
Syllabus ref. 8.5.3. Describe some
mechanisms found in Australian fauna
to ensure fertilisation and survival of
the embryo and of the young after
birth
ANIMALS EVOLVE IN RESPONSE TO CHANGING CLIMATE
Syllabus ref. 8.5.2. Identify the relationship between variation
within a species and the chances of survival of species when
environmental change occurs
Source – Prof. Gordon Grigg
Source – M. McKelvey/P. Rismiller
Echidnas show enormous variation within their species. As conditions change across their range, individuals display different
variations. Can you work out which one of these is more likely to be found in a temperate environment, and which one would
be more likely to be found in an arid region? What features/adaptations indicated this to you?
Temperate Adaptations
Arid Adaptations
Australia already has one of the highest extinction rates of flora and fauna in the world, and Global Warming is set to
push even more species to extinction. Do you think echidnas will become extinct soon? Why/why not? Briefly
explain why some species are more likely than others. to become extinct due to climate change.
Changing Ideas of Scientists
Syllabus ref. 8.5.1—Illustrate the changing ideas of scientists in the last 200 years about
individual species such as the platypus as new information and technologies became available
Extract from an article from ‘The Queenslander’, Saturday 9 June 1894
The Naturalist in North Queensland.- VI
THE DUCK-BILLED PLATYPUS
BY J.W.FAWCETT. TOWNSVILLE
The duck-billed platypus, duck-billed beaver, duck-bill, platypus, or
water mole is one of the most singular and at the same time most
interesting of the native animals of Australia, and is the most anomalous
of all Nature’s works, being in fact an animated paradox. It is the lowest
living form of the mammalia yet discovered, and forms the connecting
link between the marsupials and reptiles. As such it is one of those
wonderful connections which Nature now and then presents to us,
showing us how one form of life can develop into another. In general
appearance it is not unlike a small beaver or otter, or a large mole,
possessing the same thick fur and sleek rounded form. It is a mammal
with duck like mandibles and webbed feet, though the latter are
equipped with spurs like those of the game fowl, and with claws like
those of the true burrowing quadrupeds. The total length of a full-grown
platypus is from 18in. to 24in., the males being larger than the females.
The female lays eggs, which are afterwards hatched, and the young are
nourished by the milk of the mother exuded, or strained, from or
through the lacteal or mammary glands, for there are no nipples or
teats. How the young of the platypus were fed was for a long period an
unknown fact. The late Sir Richard Owen was the first to demonstrate
the mammalian character of the creature by the discovery of the lacteal
glands in the breast of the female, but his statement for a long while
combated by many, who declared that an animal furnished with such a
long horny beak was quite incapable of suckling.
Question 1
This scientist writes that the platypus is the ‘lowest living form of
mammalia’. Modern scientists would never write such a thing now.
What features do monotremes possess that illustrate how highly
evolved they are, and how did we become aware of these features?
Question 2
It is interesting that this scientist so casually points out the
evolutionary relationships between reptiles and mammals, and also
mentions that Sir Richard Owen was the first to place monotremes in
the class Mammalia. Sir Richard Owen was a hugely important and
influential scientist, though he clearly struggled with the implications
of evolution versus the creationist beliefs held by most people at that
time. Is this still an issue in society today, and if so how does the
scientific community deal with this issue?
Illustrations – John Gould