Evolution: A Process Of Genetic Change.

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a. AfarensisEvolution is the process that favours any genetic change that benefits changing environments. So, changes to DNA or Genes cannot be major rapid changes. Genes are the very foundation of who we are as a species, as a living organism. Such changes can only be a slow, gradual process, taking hundreds of years for the slightest, smallest observable change to occur.





Take for instance, the very first, true human example found so far. Australopithecus aferensis, generally referred to as Lucy. Lucy is 3 million years old. That’s  well over 300,000 generations from her and you and me. in excess of 300,000 generations of extremely small changes between her, 3 million years ago and us in the modern world. 300,000 generations is a very long time for the small genetic changes or the evolutionary changes that have taken place between the first true human example and modern man.

Distinctly Human: An Evolutionary Journey.

Evolution: Work In Progress.

With such small, slow, drawn out changes over such lengths of time. The general interpretation of a Missing Link is not going to happen. Such a Missing Link, is not going to be found, a missing link of skeletal remains of a half man, half ape is, well. Impossible. Such a missing link does not follow the known laws of evolution.





Modern humans did evolve from a common ancestor of humans and apes, up to 8 to 9 million years ago. What were to become humans followed one evolutionary path and what were to become the various ape species of today followed their own evolutionary paths. That common ancestor has not been found yet, we have no idea what they looked like or how they lived. That elusive common ancestor is what is referred to as The Missing Link. It is not some half man, half monkey or half ape creature

Evolutionary Thinking Through Time

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Evolutionary Thinking Was Not Unique To Darwin’s Time.

 

Charles Darwin was not the first to come up with an idea of evolution. Evolutionary thinking was not unique to Darwin’s time. By the time On The Origin Of Species: By Means Of Natural Selection was first published in 1859. Evolution was a common concept.

 

Natural SelectionEvolution is any change in the heritable characteristics of biological populations across successive generations, leading to diversity in every level of biological organisation. It includes species, individual organisms, DNA and protein molecules, using both existing species and the fossil record. Evolution is the study of universal common ancestors’ origin on Earth 3.7 billion years ago that leads to an explanation of all life on Earth. Another common misconception is that Charles Darwin first proposed evolution. This is a fallacy.





Evolutionary thinking is far back as 611-547 B.C., ancient Greek philosopher, Anaxiamander hypothesized that:

“In the beginning there was a fishlike creature with scales that arose in and lived in the world oceans. As some of these advanced, they moved onto land, shed their scaly coverings and became the first humans.”

The Roman philosopher Lucretius (99-55 B.C.) was the first to realise that all living things were related and that they had changed over time. In his book, De Rerum Natura (On the Nature of Things), Lucretius wrote:

“Wherefore, again, again, how merited is that adopted name of Earth -the Mother!


Since she herself begat the human race; and at one well-nigh fixed time brought forth each breast that ranges raving round about upon the mighty mountains and all birds aerial with many a varied shape.


But, lo, because her bearing years must end, she ceased, like to a woman worn by eld.


For lapsing aeons change the nature of the whole wide world, and all things needs must take one status after other, nor aught persists forever like itself.

All things depart; Nature she changeth all, compelleth all
to transformation.”

Aristotle, (384 BC – 322 BC) developed his Scala Naturae, or Ladder of Life to explain his idea of the advancement of living things, from inanimate matter to plants. then animals and finally man.

Georges-Louis Leclerc, Comte de Buffon in the middle to late 1700s proposed that species could change.





Erasmus Darwin, A British physician and poet in the late 1700s, proposed that life had changed over time. His poem titled, Origin of Society. Includes:

“Hence without parent by spontaneous birth

Rise the first specks of animated Earth;
From

Nature’s womb the plant or insect swims,

And buds or breathes, with microscopic limbs.

ORGANIC LIFE beneath the shoreless waves

Was born and nurs’d in Ocean’s pearly caves.

First forms minute, unseen by spheric glass,

Move on the mud, or pierce the watery mass;

These, as successive generations bloom.

New powers acquire, and larger limbs assume;

Whence countless groups of vegetation spring,

And breathing realms of fin, and feet, and wing.”

William Smith (1769-1839), developed the Principle of Biological Succession by stating:

“Each period of Earth history, has its own unique assemblages of fossils.”

Distinctly Human: An Evolutionary Journey.

Evolution: Work In progress.

Jean Baptiste de Lamarck, developed one of the first theories on how species changed. Lamarck, in 1809,concluded that organisms of higher complexity had evolved from pre-existing, less complex organisms.





It is not a mere coincidence that Erasmus Darwin shares the same surname as Charles Darwin. Erasmus Darwin was Charles Darwin’s grandfather and certainly influenced Charles’s thinking, probably throughout his entire life.

Human Population Fluctuations.

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Over the centuries leading up to the mid 20th century , the human population has fluctuated. These fluctuations were due to both natural causes and human causes. Famines, genocides, epidemics, such as plagues in Europe, Asia, and conflicts. Natural causes were probably due to an unprecedented number of volcanic eruptions.





The middle ages experienced a global warming period, causing changes in the ocean circulation and resulting in the Little Ice Age, between 1550 and 1850. This event was not a true ice age, but global temperatures decreased.

Little Ice Age

The most recent study found that an especially massive tropical volcanic eruption in 1258, followed by three smaller eruptions in 1268, 1275, and 1284 that did not allow the climate to recover, caused the initial cooling. The 1452 to 1453 eruption of Kuwae in Vanuatu triggered a second phase of cooling.

A History Of Life On Earth.

Time Of Humans: The New Legacy.

The beginning of the 20th Century, saw two major conflicts, resulting in population fluctuations: World Wars 1 and 2 between 1914 and 1918 and from 1939 to 1945, resulting in over 90 million casualties between both conflicts.





Since the beginning of the 21st Century, the Earths population has exceeded 7 billion humans. The 20th Century saw the strongest growth figures from the 1950s, witnessing its highest rate in the 1980s of 138 million births per year. Earths population has seen a steady increase from 370 million at the end of the great famine and Black Death in 1350.

Modern Humans And Natural Selection

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Evolutionary changes by Natural Selection is: Slow, Gradual changes over a lengthy period of time. From a common ancestor, leading to all modern life on Earth today. Including Humans.

It takes time, a long time for the slightest change to take place.

natural selection (modern)
natural selection

Evolutionary changes are still evident in and on the modern human body. Features that once in the Human history have had a definite useful purpose, but no longer have any significant use, for example:



  • The Wisdom Teeth (Third Molars): Earlier in human evolution, humans needed an extra set of molars to make the mouth more productive with chewing raw meat, nuts, tubers and leaves, the body lacked the ability to sufficiently digest cellulose which made the extra set of molars particularly essential. Over time our dietary requirements changed, making our extra set of molars useless.

Distinctly Human: An Evolutionary Journey.

Evolution: Work In Progress.

 

Evolution may be slowly proving the uselessness of wisdom teeth, as thirty five percent of modern humans now do not grow their third molars. Indicating the wisdom teeth may be evolving out of existence.

 

  • Appendix: modern humans have absolutely no use for their Appendix. Most scientists agree with Charles Darwin’s notion that the appendix was useful for processing cellulose, found in the earlier leaf rich diet. Over evolutionary changes, the appendix is likely to stay for a very long time, doing absolutely nothing.

 

  • The Coccyx: commonly known as the Tailbone. A remnant of, the earlier tail. A tail was handy for gripping and swinging in trees. A tailbone has no such use in modern man.



  • Goose Bumps: Modern humans get goose bumps when they are scared, cold or angry. Many animals also get goose bumps for the same reason. Goose bumps are what makes animal fur and hair stand on end when they are startled, cold or angry. When cold, it is this that creates warmth and insulation between the hairs.

 

Goose Bumps were handy in the early human evolutionary process when humans wore no clothes and instead had a natural fur coat, but no particular purpose in modern humans.

Cretaceous Origins Of Man And Mammals

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The evolution of man would have undoubtedly begun during the late Cretaceous period, 65 million years ago, the time the first Mammals appeared on Earth. The early mammals of the late cretaceous were small burrowing creatures, not unlike today’s mice, others growing to a size comparable to modern domestic cats, that were nocturnal in behaviour, to avoid the much larger Dinosaurs that were beginning to become extinct by the end of the Cretaceous period.





The mass extinction marking the end of the Dinosaur era was the beginning of the advance of mammals to the great apes, then ultimately, humans.

Distinctly Human: An Evolutionary Journey.

Evolution: Work In Progress.

Age Of The Dinosaur: The Rise and Demise.

Cretaceous Mammals
The early mammals of the late cretaceous were small burrowing creatures, not unlike today’s mice, others growing to a size comparable to modern domestic cats

The earliest primate fossils appear in the Paleocene period, 55 million years ago. The Hominidae, or Great Apes, diverged from the Hylobatidae or ape family 15-20 million years ago. 14 million years ago, Orangutans were evolving from the hominidae family. Early hominid species, the Ardipithecus coming around about 4-5 million years ago. The chimpanzee and gorilla diverged at the same time. Early hominids continued to diversify into Ardipithecus then Australopithecus then later the Homo genus.

During Charles Darwin’s time, scientists believed early humans and apes evolved from an early common ancestor. Independent analysis during the twentieth century has confirmed this with anatomical comparisons between humans, chimpanzees, gorillas and bonobos. The findings confirming, that humans and apes did indeed evolve from the same early common ancestors as apes and today, share much of their DNA.





Today, humans are still 98 percent chimpanzee. This does tend to lead to some confusion however. Although humans and chimpanzees do share certain DNA, humans are not descendent from chimpanzees. But, they do share an earlier common ancestor.

Less than 8 million years ago, a common ancestor split into different lineages. Early hominids and apes began their own independent diversification or changes, then throughout the next 6 million years, continuing their own evolutionary process eventually becoming human and ape.

Mitochondria

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MitochondriaMitochondria are organelles and contain their own DNA. In general, Known as the energy-generating powerhouse of eukaryotes, where metabolism takes place. Also with several other jobs such as oxidation of fatty acids, amino acid metabolism and the assembly of iron-sulphur clusters. They are cemented or bound by two membranes, the innermost being unfolded to form singular that takes characteristic shapes such as paddle, flat or tube shapes.





Mitochondria, is an ancestral characteristic of eukaryotes. Modern Mitochondria contains every bacterial cell known. During reproduction, the mitochondria is passed down through to the offspring by the mother.

A History Of Life On Earth.

Distinctly Human: An Evolutionary Journey.

Evolution: Work In Progress.





The origin of the Eukaryotic cell is considered a milestone for the evolution of life, since they made possible complex cells and multi cellular organisms. After this point many new groups were created, including the divergence of invertebrates and vertebrates, 670 million years ago. From these many groups, it is said that they have evolved to present day organisms.

Happy Birthday Charles Darwin.

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Today, we celebrate the birthday of the most revolutionary biological scientist ever. Charles Darwin.




February 12, 1809 was the Day English Naturalist and biologist Charles Darwin was born at the Darwin family home, The Mount, Shrewsbury, in Shropshire, England. To Robert and Susannah Darwin.

Initially, Charles Darwin chose to follow a medical career, at Edinburgh, later changing to divinity at Cambridge. In 1831, Darwin was convinced by Professor Henslow at Cambridge, to join the scientific survey ship, Beagle, taking in the Southern Oceans, the South American coast and Australia with Captain Robert Fitzroy.

Darwin... Humans

Darwins work in Biology, became the foundation scientific scientific theory on modern evolutionary studies.

Initially rocking the establishment and religious beliefs in Victorian English with his theory that all modern life, including animals and humans originated from a common ancestor. HIs theory on natural selection appealed to professional scientists to become the very foundation recognised theory on evolutionary studies.

Evolution by natural selection is no longer a theory. It is the standard model that is recognised on how all life has diversified or changed over the years, originating from a common ancestor. Diversifying into different lineages, then different species and advancing into the modern life we see all over the world today, through natural selection. Favouring any genetic changes that benefit future generations for changing environments.

Distinctly Human: An Evolutionary Journey.

Origins: The Universe, Everything and Evolution.

Charles Darwin certainly was not the first to realise that species diversify and change over time. He was how- ever, the first to collect enough evidence and so formulating his theory on evolution, through his book, Origin Of Species. – By Means of Natural Selection.

An overwhelming amount of evidence has been collected since Darwin’s time, to the extent that no argument since has successfully refuted Darwin’s claims. ‘Origin Of Species, By Means Of Natural Selection’, has become the standard explanation for life on Earth, from its origins to modern times.




Charles Darwin died on April 19, 1882. He was honoured in June, 1909, by more than four hundred officials and scientists who met in Cambridge, to commemorate the fiftieth anniversary of the publication of On The Origins Of Species, and of Darwin’s one-hundredth Birthday.

Chromosomal Adam, Mitochondrial Eve.

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Chromosomal Adam

To begin with, I would like to point out a misconception held by creationists that the existence of Chromosomal Adam and Mitochondrial Eve is proof that Scientists have admitted to their claim that all humans originated from the Biblical claim of Adam and Eve. This is a fallacy, as science relies of evidence, which can be tested and proved, not mythology or cultural beliefs.

Although the mitochondrial Eve is scientific proof that all existing humans did evolve from one female, does not assume that a chromosomal Adam existed at the same time as the mitochondrial Eve. It also does not assume that the mitochondria Eve was the only female existing at that time. In fact, there were tens of thousands of other females existing at that time. The chromosomal Adam actually existed fifty thousand to eighty thousand years after the mitochondrial Eve. The mitochondrial Eve was the originator to the human X chromosome and Adam is responsible for the Y chromosome in modern humans.

Chromosomal Adam gets its name from the Biblical Adam, and does however cause misconceptions. Chromosomal Adam was not and did not need to be the first male. He in fact lived with thousands of other males, including his father, The only difference between this Adam and all the other males of his time, No other males produced an unbroken male line leading to modern humans. Only his descendents survived. Chromosomal Adam is responsible for the Y chromosome all males possess in their mitochondria to this day.





Chromosomal Adam lived around one hundred and forty two thousand years ago. Contrary to creationists wish, Chromosomal Adam and Mitochondrial Eve would not have met during their life times.

 

DNA Double Helix

Mitochondrial Eve

Mitochondria Eve: is the most recent maternal linear ancestor, not the most recent common ancestor

Chromosomal Adam: is the most recent paternal linear ancestor, not the most recent common ancestor

The genetic material, known as the DNA in a cells nucleus controls the cell. It brings in nutrients from various parts of the body. Then makes hormones, proteins and other chemicals. The cytoplasmic matrix, or the cytoplasm contains tiny organelles that are commonly referred to as Mitochondria, which are past down from generation to generation by the mother, which are commonly referred to as “energy factories” of the cell.

Distinctly Human: An Evolutionary Journey.

Evolution: Work In Progress.

The field of human genetics, refer to mitochondrial Eve as the most common maternal ancestor, or the matrilineal ancestor of modern humans. Or, all living humans evolved from mitochondrial Eve on their mothers side, as the Mitochondrial DNA every human possesses is descended from their mothers, including the Y chromosome by definition, although the chromosomal Adam and mitochondrial Eve lived thousands of years apart.

Ancestors to modern humans were evolving into their own distinct species two hundred thousand years ago. This is the exact time that mitochondrial Eve existed. Mitochondrial eve most likely lived in east Africa, as the first Homo sapiens were becoming distinct from their earlier ancestor and other human sub-species.





Mitochondrial Eve existed earlier than the ancestor of Homo heidelbergensis and before the emergence of Homo neanderthalensis and before the migration out of Africa.

It is relatively easy to trace the lineage back to mitochondrial Eve. The mitochondrial DNA is traced unmixed from mother to children of both sexes back through the generations through the maternal side, until the DNA lineage converges. Mitochondrial DNA accumulates mutations every three thousand five hundred years on average. DNA mutations are the driving force for the evolutionary process. A certain number of variations will survive and pass onto modern lineages as a distinct lineage.