8.5
Evolution of Australian
Biota
Part 1
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
1
Table of Contents
Part 1 - Organisms are made out cells that have similar structural characteristics
1.
2.
3.
4.
5.
6.
Syllabus………………………………………………………………..Page 3
Terms and Definitions…………………………………………………Page 4
1.2.1 Evidence for continental drift………………..…...……………. Page 6
1.3.1. The moving Australian continent…...…………………………..Page 7
1.2.2. Evolutionary relationships……………….. ………...……….....Page 8
1.3.2. Changing ideas of scientists………………………......…...……Page 9
1. Evidence for the
rearrangement of
crustal plates and
continental drift
indicates that
Australia was once
part of an ancient
super continent
Students learn to:
Students:
identify and describe evidence
that supports the assertion that
Australia was once part of a
landmass called Gondwana,
including:
matching continental margins
position of mid-ocean ridges
spreading zones between
continental plates
fossils in common on
Gondwanan continents,
including Glossopteris and
Gangamopteris flora, and
marsupials
similarities between presentday
organisms on Gondwanan
continents
solve problems to identify the
positions of mid-ocean ridges
and spreading zones that infer a
moving Australian continent
identify data sources, gather,
process and analyse information
from secondary sources and use
available evidence to 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
discuss current research into the
evolutionary relationships
between extinct species,
including megafauna and extant
Australian species
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
2
Evolution of Australian Biota
Terms and Definitions
Pangaea
Gondwana
Continental Drift
Plate tectonics
Mid ocean ridges
Spreading zones
Continental margins
Subduction
Divergent boundary
Convergent boundary
Transform boundary
Glossopteris
Nothofagus
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
3
Ratites
Megafauna
Living fossil
Placental mammal
Marsupial
Monotreme
Evolution of Australian Biota
Australia’s unique flora and fauna has been shaped by a history of belonging to a great Southern
supercontinent, Gondwanaland, followed by millions of years of separation as Australia drifted slowly
northwards becoming drier and warmer.
The study of past environments and of paleontology supplies information about what has occurred and
thus about what may happen in the future.
Evidence that Australia once belonged to Gondwanaland has built up over the past half a century. It comes
from:
1. logical similarities found between flora and fauna (in living and fossils)
2. geological evidence
Read pgs: 234 – 242 Biology in Focus
1.2.1 Evidence for Continental Drift
The evidence that supports the theory that Australia was once part of a landmass called Gondwana comes
from various sources including:
1. matching continental margins
2. the position of mid-ocean ridges
3. spreading zones between continental plates
4. the presence of common fossils on Gondwanan continents
5. similarities between present day organisms on Gondwanan continents
Activity 1
Complete the following questions:
Matching Continental Margins
A look at the shapes of continents on a world map reveals that some seem to fit together like pieces of a
jigsaw
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
4
e.g. South America and __________________________________
e.g. ______________________________________ and Antarctica.
Position of Mid-Oceanic Ridges
Deep sea mid-oceanic ridges occur where the plates are _________
________________________, pushed apart by the magma moving
up to the surface.
New rock is formed at the mid-ocean ridges.
Spreading Zones between Continental Plates
New rock is formed at mid-ocean ridges as magma pours out from beneath the surface. In areas called
subduction zones, the oceanic crust is pushed below the continental crust. The worlds volcanoes and
earthquakes are found where these regions of subduction and collision occur. As new rock forms at midoceanic ridges and older rock is subducted at plate edges, so the crust moves and carries the Earth’s
continents
Common Fossils on Gondawanan Continents
If similar fossils are found on different continents it can be inferred that these continents were once close
together or there was some way for the organisms to travel between these continents.
Questions:
1. List where Glossopteris fossils
have been found
______________________________
______________________________
______________________________
2 List where Lystrosaurus fossils
have been found
______________________________
______________________________
______________________________
Similarities between present day organisms on Gondwanan continents
As well as finding similar fossils that show past links between the Gondwanaland continents, it is possible
to see links through the organisms that are found on these continents today.
Activity 2
Research and write a summary on each of the following
e.g. Marsupials (pouched animals) are found in Australia, South America and New Guinea
e.g. Nothofagus:
_____________________________________________________________________________________
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
5
_____________________________________________________________________________________
_____________________________________________________________________________________
e.g. Flightless birds:
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
Activity 3
Answer the question:
1. Outline the theory of Continental Drift.
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
1.3.1. The moving Australian continent
The tectonic plate boundaries can be either convergent (moving towards each other) or divergent (moving
apart from each other)
 Divergent boundaries form mid-oceanic ridges
You are to find the position of mid-oceanic ridges and plot their location on the map provided.
Website: http://www.marinebio.net/marinescience/02ocean/mgtectonics.htm (7th diagram on
page)
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
6
Questions:
1. How does the position of mid-ocean ridges (places of plates spreading) infer a moving Australian continent?
__________________________________________________________________________________________
__________________________________________________________________________________________
2. Describe the movement of the plate that Australia belongs to.
__________________________________________________________________________________________
__________________________________________________________________________________________
4.1.2 Evolutionary Relationships
Read pgs: 275 – 277 Biology in Focus
Activity
Answer the following questions:
1. What is the megafauna?
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
7
__________________________________________________________________________________________
2. Give some examples of Australian megafauna and describe them.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
3. Discuss the two current theories to explain the disappearance of these animals.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
4. State one argument for and one argument against each theory.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
8
The Wollemi pine is an example of species that had thought to be extinct but has recently been discovered to be
growing in isolated pockets in NSW. This plant has gone from being thought as extinct to extant (currently
living) It has features that make it different from all living pines and is more closely related to fossil species that
lived in Australia 50 mya.
5. Give another example of a ‘living fossil’
__________________________________________________________________________________________
6. What is the evolutionary relationship between the megafauna and extant Australian species?
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
1.3.2. Changing Ideas of Scientists
As more research and advancements in technology over the years have improved scientists have had changing
ideas about individual species such as the platypus.
Read pgs 247-250 Biology in Focus
Read the above pages and answer the following questions:
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
9
1. Outline ideas held 200 years ago about the platypus and its relationship to other individual species.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
2. State the main difficulty involved in trying to classify the platypus.
__________________________________________________________________________________________
__________________________________________________________________________________________
3. Outline the ‘new idea’ in science—how the platypus is classified today compared with the
confusion of 200 years ago.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
Read the following information at these websites and complete the table below
http://www.allempires.com/article/index.php?q=The_Platypus
http://www.talkorigins.org/faqs/platypus.html
http://www.nhm.ac.uk/about-us/news/2008/may/news_14229.html (read section on DNA analysis and
unique monetreme for DNA section)
Discovery
How discovery Made
Changed Idea
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
10
First discovered in 1797
Found in Hawkesbury River
Confirmation of being a
Genuine species 1799
Examined by brittish scientist
19th Century –Platypus
lays eggs
Platypus anatomy and sex
Life was studied
Was thought to be a combination of a reptile,
Mammal and fish (thought to be a hoax)
Similar to ducks
1984 Fossil evidence
Present – DNA analysis
M. Heyman Patrician Brothers’ College, Fairfield updated S.Fellows, 2012
11