Charles Darwin's Theory

THEORY OF CHARLES DARWIN
Darwin's Theory of Evolution is the widely held notion that all life is related and has descended from a common ancestor: the birds and the bananas, the fishes and the flowers -- all related.

Darwin's general theory presumes the development of life from non-life and stresses a purely naturalistic "descent with modification".
That is, complex creatures evolve from more simplistic ancestors naturally over time. In a nutshell, as random genetic mutations occur within an organism's genetic code, the beneficial mutations are preserved because they aid survival -- a process known as "natural selection."
These beneficial mutations are passed on to the next generation. Over time, beneficial mutations accumulate and the result is an entirely different organism .






Darwin imagined it might be possible that all life is descended from an original species from ancient times. DNA evidence supports this idea.
5 observations by Darwin
- Species have great fertility. They make more offsprings that can grow to adulthood.
- Populations remain roughly the same size, with modest fluctuatuions.
- Food resources are limited, but are relatively constant most of the time.
From these 3 observations, the may be inferred that in such an enviroment there will be a struggle for survival among individuals.
- In sexually reproducing species , generally no 2 individuals are identical.
- Variation is rampant
*Much of this variation is heritable.

CONCLUSION OF CHARLES DARWIN'S THEORY
From this it may be inferred: In a world of stable populations where each individual must struggle to survive, those with the "best" characteristics will be more likely to survive, and those desirable traits will be passed to their offspring.

These advantageous characteristics are inherited by following generations, becoming dominant among the population through time. This is natural selection. It may be further inferred that natural selection, if carried far enough, makes changes in a population, eventually leading to new species. These observations have been amply demonstrated in biology, and even fossils demonstrate the veracity of these observations.

Ω Variation:
• There is variation in every population.
Ω Competition:
•Organisms compete for limited resources.
Ω Offspring:
Organisms produce more offspring that can survive.
ΩGenetics:
•Organisms pass genetic traits on to their offspring
Ω Natural Selection:
•Those organisms with the most beneficial traits are more likely to survive and reproduce

Evolution

MORE ON HUMAN EVOLUTION
The evidence of the descent of man from a lower form
- The reproduction of the species is strikingly the same in all mammals, from the first act of courtship by the male, to the birth and nurturing of the young.
-Monkeys are born in almost as helpless a condition as our own infants; and in certain genera the young differ fully as much in appearance from the adults, as do our children from their full-grown parents.
-So the correspondence in general structure, in the minute structure of the tissues, in the general structure of the tissues, in the chemical composition and in constitution, between man and the higher animals, especially the anthropomorphous apes, is extremely close.
-The Similarity in the POSTERIOR MOLAR (wisdom tooth)
These teeth are rather smaller than the other molars, as is likewise the case with the corresponding teeth in the chimpanzee and orang utan; and they have only two separate fangs. They are much more liable to decay and are earlier lost than other teeth.
-Similarity in the appendage
It is useless, and sometimes the cause of death: this is due to small hard bodies , such as seeds entering the passage and causing inflammation.
-Similarity in mental faculty

Amphibious Developement

MORE ON AMPHIBIOUS DEVELOPMENT
• These fishes- coelacanth had an advantage over other fishes as they had lungs and could breathe
on land. In time of shortage of water, these fishes came out of the pools which were drying out on
their muscular fins to search for other water. They might have added insects and other small
arthropods to their diet while moving and over time became less dependent on water.
• Earliest frogs, dating from the Jurassic Period, evolved south of the Equator

Natural Selection

MORE ON NATURAL SELECTION
1: Natural selection acts to preserve and accumulate minor advantageous genetic mutations.
2: Natural selection is the naturalistic equivalent to domestic breeding.
3: Over the centuries, human breeders have produced dramatic changes in domestic animal.
populations by selecting individuals to breed.
4. Breeders eliminate undesirable traits gradually over time. Similarly, natural selection eliminates inferior species gradually over time.