QUEENSLAND 
Brisbane EVOLUTION. 
THE TRANSMUTATION OF SPECIES. 
O RGANIC EVOLUTION is ihe science o( the facts, processes and laws 
involved in the cl ranges of organisms. It teaches that all living things, 
plants and animals, have come Irom earlier forms. It is the study of the 
tor< es winch govern the derivation of species Irom ancestral organisms. 
According to Evolution there is no break in the chain of life. Everything has 
come Irom something else, and, in a wide sense, all living things form one family. 
In su> cessivo periods in the history of the wmld higher and higher animals came 
into bring In thr Silurian, hdn s made their appearance. Amphibians in the 
Carboniferous, Reptiles in the Permian, Birds in the -Jurassic. Later came 
Mammals, and then Man himstfff. In Us widest sense Evolution treats of the 
history of every form of matter and force in the universe f he term Darwinism 
is sometimes used as synonymous with Evolution, because Charles Darwin did so 
much to explain the process. The word Evolution often suggests philosophical 
assumptions with which science has nothing to do TheDoctnne of Descent 
is thus a prelerable term for the general theory 1 of Organic Evolution, whilst 
the word Bionomics (Bios, life, Nomos, order or custom), First suggested hv 
Prof. Patrick. Geddes, is also coming into use 
The doctrine is illustrated by a large number of fads, taken from every 
branch of science, among which may be summarised : — 
ANATOMICAL DATA: 
The facts of classification that species lades Into species, that 
genus is linked to genus, that genealogical trees are suggested. 
Remarkable cornier ting links give "an impression of otTiljalion" 
between groups. 
A recognition of homologies that is, of structural and developmental 
similarities. Thus the wing of a bird, the fore-leg of a horse,, 
the flipper of a whale, the wing of a bat. the arm ol a man, 
show homologies not only as regards the bones, but also as 
to muscles, nerves and blood vessels. 
Vestigial structures, to which the 4 * Doctrine of Descent is the only 
key. Die anatomist Wiedersheim has recorded 180 of these 
structures in man, among which may be mentioned the 
verrniloim appendix and the muscles of the external ear. 
The splint bone of the horse and the useless vestiges of limbs 
in certain snakes air familiar examples of funclionless structures 
in animals. 
PAL/EONTOLOGICAL DATA: 
I lie historical evidence ol the lineage ol the horse Irom ancestors 
with lour toes* is illustrated in this Museum Another 
convincingly clear ancestral tree has been tracer! of the 
elephant, with its long tusks, Irom lapir-like ancestors with 
ordinary incisor Uelh 
In the Tnassic section of the Mesozoic cases in the Possil Court 
of this Museum is shown a cast of the Archaeopteryx, usually 
accepted as a link hetweeri the Birds and Reptiles 
EMBRYOLOGICAP DATA 
It is generally recognised that an animal of plant is apt to reproduce, 
during its embryonic development, some of the stages of its 
ancestry in past linn- 1 bus there are residues of gill-clefts 
in the development ol every reptile, bird and mammal, and 
teeth in the baleen whale which never cut the gum. 
BLOOD RELATIONSHIP : 
When the blood of a Imrs is Ifanslused into an ass, that ol a hare 
into a rabbit, or that of an orang into a gibbon, or that of a 
man into a chimpanzee, there is a harmonious mingling of the 
two. Bui when human blood is transfused into an eel, pigeon, 
horse, dog, cat. lemur or non- anthropoid ape, there is no 
harmonious mingling The human blood serum behaves in a 
hostile way to the other blood, causing a disturbance, marked, 
for instance, by the destruction of red blood corpuscles The 
difference in the two sets ol cases is that in the first the 
organisms are closely related ; in the second they are not. 
EVOLUTION TO-DAY : 
Evolution is in actual profess, to-day. as is. shown by the develop- 
ment of cultivated plants, such as new cereals, plums, berries, 
&c. Organs and organisms are still changing With the 
separation of individuals by barriers of land and water and 
varying climate, differing lines of descent are brought into 
existence Owing to a necessarily limited period of observation, 
the majority of these changes escape definite notice. 
METHODS OF EVOLUTION. 
There is no unanimity of ©pinion imong Biologists as to the Factors or 
Methods of Evolution. Some scientists believe that the production of new forms 
is a function ol variation, and that species do not arise slowly, but by sudden 
changes. Others lay stress on what are known as Lamarckian factors — that 
changes in environment directly bring about changes in the habits of animals. 
I he best known theory is that of Naiural Selection, which may be summarised 
as follows: 
NATURAL SELECTION : 
Living creatures are very prolific.. More organisms are born than 
can survive. Thr maionty rife young. 
No two individuals of the same species are exactly alike Variations 
are of common oc cu trnce, and some of them are transmissible. 
I here is a ceaseless struggle for food and place a struggle for 
> xistc-n c The Survival of the Fittest. IS the outcome. . Natural 
Selection tends to maintain the balance of living things and 
the r surroundin'. s. When the environment changes, living 
