The Piltdown hoax was a anthropological discovery in the early 1900's in Piltdown, England. Charles Dawson, a fossil hunter, was searching in the hills of Piltdown when he came across a fragment of a skull and jawbone. He touted this as the fossil of an ancient ancestor of modern Englishmen, for England had no Neanderthal discoveries compared tot he surrounding countries. Dawson's hoax was believed to be the final evidence needed to solidify Charles Darwin's claim that man evolved from apes as the jawbone contained teeth that were flat where exposed much like the teeth of humans. However these fossil were in fact from apes and the teeth had been ground down to match human's own teeth.
This hoax served as ego inflation for the English scientific community as well as human kind, which we believed this discovery established our dominance as a species.Scientists were so eager to find such a fossil, that it went un-tested of the most basic tests for over 40 years. The competition to make ground breaking discoveries was fierce which may have lead to the resulting hoax as well. This foul-up stunted the scientific process, as this piece accepted as real evidence misled scientist to make inaccurate conclusions about our history and place in the world.
Some in the scientific community was still skeptical though as the jaw missed two important pieces, the canine tooth and the connection to the rest of the skull (this piece was broken off). A year later the canine was discovered as well as another Piltdown man. For years these discoveries were hailed as truths and many feared to speak otherwise as Piltdown became the status quo. However finally the Natural History Museum had the remains tested for their nitrogen content, only to find they weren't as old as they should be and when examined under a magnifying glass, found fresh grind marks in the teeth as if they had been filed down. When these finds did not add up, they then chemically tested all the artifacts to find that they all were hoaxes, the jaw was quite modern and had been stained to look like a fossil and the canine was crudely filed and painted with everyday paints. Many scientists were outraged as they had accepted this hoax as fact and even dedicated their lives to studying what they thought was a break through.
This entire hoax was founded on human error and as much as the scientific process aims to reduce the chances of such an occurrence, the unfortunate reality is that the scientific process is man-made, thus it is essentially impossible to create a completely human error free process of testing discoveries. However, if removing humans from the scientific process were possible, it would also remove the passion for science and discoveries that we share, and science would possible reach a plateau.
The lesson I take from this, which is way too relatable at the moment, is to not be swept up in passion and excitement of new finds; to always look at the facts before diving into a new craze. This is also very relatable politically given all the name calling and story telling that goes on in the media.
Tuesday, January 26, 2016
Tuesday, January 19, 2016
Homologous and Analogous Traits
Homologous Traits
Cats and humans are both mammals that have hair, give live birth and produce milk. Another trait that the both share, a homologous trait is the structure of their limbs. Humans and cats share the same bone structure in the arms. Though most of the bone structure is strikingly similar with the exception of size, the cats upper humerus bone became curved for ease of walking on all fours. Humans learned to walk straight and developed apposable thumbs allowing them to grip things but no longer walk on their hands. Whereas cats developed paws and claws for walking, climbing, and catching prey. These differences in the paw and hands and curvature of the humerus occurred because of the different functional needs applied to the animals in the form of environmental pressures.
According to National Geographic Researchers who studied the skeletons of 86 different species and over 4,500 anatomical homologous traits, the common ancestor of all cats, humans, bats, whales and mice looked like the image below, called the Ancestral Placental Mammal.
Analogous Traits
Bats and insects may have the common trait of wings however this is analogous trait because the two species did not have a common ancestor that passed down this trait to them. Instead this, like a paw and hand example, is a result of evolution in that environmental pressures cause the forelimbs of these two animals to develop in to flight capable wings. This trait is also analogous because the function is the same but the structures are quite different. Bats have bones similar in structure to humans underneath the skin however insects have veins that make up the frame of the wings and membrane that covers each cell created between the veins.
If we went far enough back for these two species however this ancestor would not posses the trait of wings because the wing trait was a result of later environmental pressures.
Cats and humans are both mammals that have hair, give live birth and produce milk. Another trait that the both share, a homologous trait is the structure of their limbs. Humans and cats share the same bone structure in the arms. Though most of the bone structure is strikingly similar with the exception of size, the cats upper humerus bone became curved for ease of walking on all fours. Humans learned to walk straight and developed apposable thumbs allowing them to grip things but no longer walk on their hands. Whereas cats developed paws and claws for walking, climbing, and catching prey. These differences in the paw and hands and curvature of the humerus occurred because of the different functional needs applied to the animals in the form of environmental pressures.
According to National Geographic Researchers who studied the skeletons of 86 different species and over 4,500 anatomical homologous traits, the common ancestor of all cats, humans, bats, whales and mice looked like the image below, called the Ancestral Placental Mammal.
Analogous Traits
Bats and insects may have the common trait of wings however this is analogous trait because the two species did not have a common ancestor that passed down this trait to them. Instead this, like a paw and hand example, is a result of evolution in that environmental pressures cause the forelimbs of these two animals to develop in to flight capable wings. This trait is also analogous because the function is the same but the structures are quite different. Bats have bones similar in structure to humans underneath the skin however insects have veins that make up the frame of the wings and membrane that covers each cell created between the veins.
If we went far enough back for these two species however this ancestor would not posses the trait of wings because the wing trait was a result of later environmental pressures.
Saturday, January 9, 2016
Wednesday, January 6, 2016
Historical Influences (Week 1)
Jean-Bauptiste Lamarck, a French naturalist, is arguably one of the most notable figures whose theories helped Darwin's famous theory of evolution. Lamarck believed that the changes in the environment caused changes in the species behavior which caused a change in a species characteristics as a result of needing to adapt to their environment in order to survive, these traits were then passed down to the offspring to continue the survival of the species. Even though we now know that genetics do not work the way Lamarck theorized, his theory which laid the ground work for Darwin's own theory. While Lamarck's theories are discredited and even mocked by Darwin and other anthropologists, Darwin admitted that Lamarcks theory of use and disuse (in that certain organs are rendered nonfunctional due to not aiding in the animals survival) did help Darwin in his own theory and was even shown plausible in the case of moles. According to Uucmp.berkeley.edu and Darwin "the vestigial eyes of moles and of cave-dwelling animals are "probably due to gradual reduction from disuse, but aided perhaps by natural selection.""
Darwin's theory is that animals with the traits better suited for their environment would have the likelier chance of surviving, such that the chances of having the more suitable traits is random and most often (except for in the case of humans) uncontrollable. It is this theory that was shaped by Lamarck's, albeit wrong, theory of evolution. He believed, as illustrated by the Introduction to Physical Anthropology text book, that the long neck of the giraffe was due to the giraffe's need to reach leaves (food) higher up in the trees. He believed that this change in the neck length was due to the giraffe stretching its neck higher as needed, and the trait passing on through reproduction. Lamarcks theory supports the idea that survival is only possible through evolution and the changes in species are transmitted through reproduction as Darwin believes but genetics has shown that traits that change after birth do not pass on in this way. Darwin, having a better understanding of genetics, adapted this theory in that species born with the more favorable variation of traits to suit their environment are more likely to have better access to the resources, a better chance at surviving and a better chance at reproducing or passing on those more favorable traits.
Darwin, or any other theorist could not have built their theories on their own. Science is a building of knowledge upon prior knowledge, be it rejecting, accepting or adding on to or even retesting that prior knowledge. It is because of the nature of science and the scientific method that Darwin could not have developed his theories on his for he had to have had prior knowledge to build upon-be it the rejected theory of Lamarck that species can change their own characteristics to survive as well as pass them on, or the expanded upon theory that animals evolve to survive in their changing environments, or even the acceptance of the theory that organ can be rendered not functional if they have gone unused for a prolonged amount to time.
Darwin was hesitant on releasing his book, On the Origins of Species, because the Reform Movement in Britain had taken head, during which many radicals like atheists (who favored and supported theorists like Lamarck) had started to speak out against the church. Thus evolution had become synonymous with atheism. With this perception attached to his work, Darwin feared publishing his work to the Church dominated public could cause backlash towards him and his family as well as receive harsh reactions from the Church. His wife was also quite religious which caused strife between them. However, Darwin had written to another theorist, Alfred Russel Wallace, and feared that if he did not publish then, Wallace could steal Darwin's ideas and pass them off as his own. A year later, Darwin published his longest surviving piece to date, On the Origins of Species.
Darwin's theory is that animals with the traits better suited for their environment would have the likelier chance of surviving, such that the chances of having the more suitable traits is random and most often (except for in the case of humans) uncontrollable. It is this theory that was shaped by Lamarck's, albeit wrong, theory of evolution. He believed, as illustrated by the Introduction to Physical Anthropology text book, that the long neck of the giraffe was due to the giraffe's need to reach leaves (food) higher up in the trees. He believed that this change in the neck length was due to the giraffe stretching its neck higher as needed, and the trait passing on through reproduction. Lamarcks theory supports the idea that survival is only possible through evolution and the changes in species are transmitted through reproduction as Darwin believes but genetics has shown that traits that change after birth do not pass on in this way. Darwin, having a better understanding of genetics, adapted this theory in that species born with the more favorable variation of traits to suit their environment are more likely to have better access to the resources, a better chance at surviving and a better chance at reproducing or passing on those more favorable traits.
Darwin, or any other theorist could not have built their theories on their own. Science is a building of knowledge upon prior knowledge, be it rejecting, accepting or adding on to or even retesting that prior knowledge. It is because of the nature of science and the scientific method that Darwin could not have developed his theories on his for he had to have had prior knowledge to build upon-be it the rejected theory of Lamarck that species can change their own characteristics to survive as well as pass them on, or the expanded upon theory that animals evolve to survive in their changing environments, or even the acceptance of the theory that organ can be rendered not functional if they have gone unused for a prolonged amount to time.
Darwin was hesitant on releasing his book, On the Origins of Species, because the Reform Movement in Britain had taken head, during which many radicals like atheists (who favored and supported theorists like Lamarck) had started to speak out against the church. Thus evolution had become synonymous with atheism. With this perception attached to his work, Darwin feared publishing his work to the Church dominated public could cause backlash towards him and his family as well as receive harsh reactions from the Church. His wife was also quite religious which caused strife between them. However, Darwin had written to another theorist, Alfred Russel Wallace, and feared that if he did not publish then, Wallace could steal Darwin's ideas and pass them off as his own. A year later, Darwin published his longest surviving piece to date, On the Origins of Species.
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