What did Mary Anning do
Mary Anning 1799-1847 lived her entire life in the Lyme Regis on the Dorset coast in England. She was a women, born to a poor family, with minimal education (even by 19th century standards). Despite this she was eventually able to influence the greatest scientists of the day with her fossil discoveries and her subsequent hypotheses regarding evolution.
She lived during the Industrial Revolution, during which scientific discoveries set the stage for great leaps of knowledge and understanding about humans and the natural world.
Despite the expectations of society at the time, Anning became a highly successful fossil hunter as well as a self-educated geologist and anatomist. The geology of Lyme Regis is now called the Jurassic Coast, and it provided a rich source for fossilized remains.
Searching for fossils amongst the cliffs was dangerous, and in 1833 Anning lost her beloved dog in a landslide, nearly along with her own life.
Around the age of 10, Anning located and excavated a complete fossilized skeleton of an ichtyosaurus. She eventually found Pterodactylus macronyx and a 2.7 m Pleiosaurus. These discoveries proved there had been significant changes in the way living things appeared throughout the history of the world.
she helped provide physical evidence to support the theory of evolution, which would eventually result in Darwin’s seminal work.
At the time Anning wasn’t allowed into the Geological Society of London for being a Women, and she received little recognition for her contributions in her day.
How did Uniformitarianism occur
A few centuries ago, western Christian tradition had huge influence on scientific theory. The bible did not allow for long, slow processes of geological or evolutionary change to operate.
In the 18th century, James Hutton’s work on the formation of earth provided a much longer timeline of events that the bible would allow. Hutton’s theory of deep time was crucial to understanding fossils, and giving enough time for continental drift, evolution, and fossilization.
Charles Lyell propelled Hutton’s into his own theory of uniformitarianism, which says that Earth’s geological formations are the work of slow geological forces. His three-volume work, Principles of Geology was influential on Darwin.
Describe Geologic time
Using various precise dating methods based on physics and chemistry, scientists have established the age of the earth to be roughly 4.6 billion years old. The first evidence for life appears around 3.5 billion years ago.
Geologic time is broke down into eons, which are broken into eras, which are divided into periods, which are comprised of epochs. We currently live in the Phanerozoic eon, Cenozoic era, Quaternary period, and probably the Holocene epoch (though there is some debate)
These divisions are based on major changes and events recorded in the geologic record, such as significant climate shifts, mass extinctions, etc. These borders are not real in a physical sense, but are helpful organizational guidelines for scientific research.
What is the current epoch
While we are currently in the Holocene epoch, which began 12,000 years ago, during the warming period of the last major ice age. There is some push to classify a new epoch beginning in 150 with the nuclear age and rapid climate change, this would be called the Anthropocene. (Though some put it earlier, at the dawn of the industrial revolution, or the advebt of agriculture.
What is Taphonomy
Taphonomy is the study of what happens to an organism after death. It includes the study of how an organism become a fossil.
Taphonomy analysis can give us insights into the development of complex thought and ritual in human evolution, allow use to study human remains, and faunal remains in archaeological sites.
What can Taphonomy tell us
Things like deliberate burials have certain patterns such as a specific position for the body, such as supine (on the back) with arms crossed over the chest, or in the fetal position. If bones have evidence of a carnivore or rodent gnawing on them, it can be inferred that the remains were exposed to scavengers after death.
Taphonomic evidence can also tell us how our ancestors died. This includes carnivore tooth marks and punctures on australopithecines, cut marks made by stone tools indicating possible defleshing in Homo erectus, and the scavenging of at least 51 Homo erectus by cave hyenas.
What do peat bogs do
Peat bogs form from the accumulation of vegetation and silts in ponds and lakes. Individuals buried in bogs have exceptionally well preserved hair, skin, clothes, and organs. Individuals from thousands of years ago can have identifiable last meals or tattoos.
who was Otzi
Extreme cold can also halt natural decay. ötzi is a man who died over 5,200 years ago and had his hair, skin, clothes, and organs well preserved by extreme cold.
what is Capachocha
In the Andes, ancient people would bury human sacrifices throughout the high peaks in a ritual called Capacocha. The best preserved mummy to date is called the Maiden or Sarita, who was a 15 year old girl who died over 500 years ago, but looks like it was yesterday
what can arid conditions do
There are also several examples of arid environments spontaneously preserving human remains, including catacomb burials in Austria and Italy. This occurs because much of the bacteria active in breaking down bodies is in our buts, and arid environments deplete the bacteria of the moisture it needs to function.
What needs to happen first for fossilization
For fossilization to occur, several important things must happen. First, the organism must be protected from things like bacterial activity, scavengers, and temperature, and moisture fluctuations. A stable environment that doesn’t expose the body to significant fluctuations in temperature, humidity, and weather patterns.
Changes to moisture and temperature cause the organic tissues to expand and contract repeatedly, which causes microfracture and break down. Soft tissues break down more easily, so bones and teeth last longer and are more common in the fossil record.
How can wetlands be good for fossils
Wetlands are good for preservation as they allow rapid permanent burial and a stable moisture environment. Waterlogged sites can also be naturally anaerobic, which slows or halts the decay process where oxygen is necessary for the body’s bacteria.
What is the second step for fossilization
The next step is sediment accumulation. The sediments cover and protect the organism from the environment. They, along with water, also provide the minerals the eventually become the fossil along with the pressure needed for mineralization. Lithification squeezes out extra fluids and replaces the voids with minerals from surrounding sediments. Finally, permineralization, this is when the organism is fully replaced by minerals from the sediments.
A fossil is really a mineral copy of the original organism.
Describe Plant fossils
Plants are the most common fossils, with ferns being very common. We can also see extinct plants, including the ancestors of modern plants.
Petrified wood is created when actual pieces of wood are mineralized and turn into rock. It is a combination of silica, calcite, and quartz, and it is both heavy and brittle. Can also be colourful and generally aesthetically pleasing as the features of the original tree’s composition are illuminated through mineralization.
Describe Homini fossils
The term hominins includes all human ancestors who lived after the human split form the Chimpanzee and Bonobo lineage, around 6-7 mya.
Lucy is a 3.2 million year old Australopithecus afarensis discovered in Ethiopia in 1974. 40% of her skeleton was preserved, and was the most complete and oldest hominin fossil for a while.
In 1994, an Australopithecus fossil named Little Foot was found in the Sterkfontein caves in South Africa. More complete than lucy and around 3.6 million years old. Ankle bones revealed she was likely bipedalism.
Both Lucy and Little Foot were from the Pliocene (5.8-2.3 mya).
Older hominin fossils from the Miocene (7.25-5.5 mya) have been located, but they are much less complete. The oldest is a fragmentary skull named Sabelanthropus tchadensis found in norther Chad from 7mya.
Describe Asphalt
Asphalt is a form of curde oil which can yield fossilized remains, it is commonly called tar because of its viscous nature and dark colour (though it is not real tar).
The La Brea Tar Pits in California provides an incredible look at the animals that lived in the Los Angelas Basin 40,000-11,000 years ago. Excavations have revealed millions of fossils, including American Mastodons, Canis dirus, SMilodon fatalis, plants, and one person “La Brea Women”.
La Brea Women was found in 1914 and dated to 10,250 years ago, she was 17-28 yrs old when she died, and less than 5ft tall. Thought to have died from blunt force trauma to the head, making her the first document homicide in Los Angeles.
Describe Igneous rock fossils
While most fossils are sedimentary rock, some fossils are found in Igneous rocks. Around 2% of all fossils have been found in Igneous rock. Part of a giant rhinocerotid skull dating back 9.2 mya to the Miocene was discovered in Cappdocia, Turkey in 2010. The eruption of the Cardak cladera was so sudden it simply dehydrated and baked the animal.
Describe trace fossils
Foot prints can be fossilized under the right conditions, they are considered trace fossils. Other trace fossils include nests, burrows, tooth marks, and shells.
The Laetoli footprints in Tanzania, along with White Sands footprints in New Mexico are two famouns trace fossils from Hominins.
At Pech Merle cave in the Dordogne region of france, archaeologists discovered two fossilized footprints. They then brought indigenous trackers from Namibia to look for other footprints, leading to foot prints from as many as five individual people from 12,000 years ago.
What are Bezoars
Bezoars are hard, concrete-like substances found in the intestines of fossilized creatures. Bezoards start off like the hair balls that cats and rabbits accumulate from grooming, but become hard, concrete like substances in the intestines. If an animal with a hairball dies before expelling the mass, and becomes fossilized, the mass becomes a bezoar.
What are coprolites
Coprolites are fossilized dung. One of the best collections of coprolites is called the “Poozeum” and containes a huge coprolite called “Precious”. Coprolites can be in matrix (embedded in secondary rock). Coprolites tell scientists a lot about the diet and environment of the animal.
For instance, 65 million year old grass phytoliths found in dinosaur coprolite in India revealed that grasses had been in existence early than previous thought.
What are Pseudofossils
Pseudofossils are misinterpretations of rocks that look like true fossilized remains. They are the result of impressions or markings on rock, or even the way other inorganic material reacts with the rock.
Dendrites are crystallized deposits of black minerals that resemble plant growth.
Other examples of pseudofossils are unusual or odd shaped rocks that include various concretions and nodules.
Describe Necropolitics
Necropolitics is an application of critical theory that describes how “governments assign differential value to human life” and similarly how someone is treated after they die.
For example the La Brea Women’s remains were display without consent from the native tribes of the area. They also attached the skull to the ancient remains of a pakistani female the was dyed dark bronze, the femurs shortened to approximate the stature of the native pople.
Indigenous remains are now protected in the US, and consultation with native tirbes is needed before archaeological work is done on their land.
What are some dating methods
Context for fossils is very useful to properly understand the significance of a find. Being able to place it in time allows us to compare a fossil with other to understand variation at that time, evolution, and other things
Unfortunately many dating techniques require the destruction of part of the remains.
Describe relative dating
Use observational skills, don’t tell absolute dates, just what is older than what.
Stratigraphy is the first relative dating technique. The law of superposition says that things on top are younger in geologic strata.
Another relative dating technique is biostratigraphy, this compares a fossil to other fossils in the layer to determine its age based on the fauna that lived alongside it.
Cultural dating is used to identify the chronological relationships between human-made artifacts. Based on artifact type and styles. Some artifacts are specific to different time periods, similar to biostratigraphy.
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1b - Evolution of Evolutionary Theory31
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2a - Intro to genetics15
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2b - Ancient DNA13
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3a - Biology of Variation25
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3b - Mechanisms of Evolution18
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4a - Primates30
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4b - Primate Behaviour and Ecology28
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5a - Primate Evolution29
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Ch859
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Ch726
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Ch 60
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Ch 547
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Hominin Origins15
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Earliest Hominins19
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Mid-Late Pleistocene Hominins I: Eurasia16
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Mid-Late Pleistocene Hominins II: Asia and Africa13
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Modern Humans: Origins, Dispersals, and adaptation20
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Modern Humans 2: Origins, dispersals, and adaptations23
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Modern Human Variation14
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Understanding Human variability: Dismantling the concept of race22
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Climate and Human evolution20
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The influences of health and disease on contemporary humans22
