Final Exam Flashcards
Fossils
the mineralized copies of once-living organisms
They used to believe in the Bible but now they don’t after realizing that they found fossils that are older than the Bible
Why was there such resistance to the idea that animals and people may have evolved over time?
To even consider that humans and animals might have evolved over time was practically an admission that the Christian God had made mistakes that needed correction in His creation of Earth and all living things. To think otherwise was considered heresy and was punishable by ex-communication from the Church—or even death. Instead, scientists were still trying to fit geologic evidence into Biblical chronology
Deep Time
Helped us understand how the formation of the Earth would support the theory of evolution.
Scotsman James Hutton’s theory gave the history of Earth enough time—4.543 billion years—to encompass continental drift, the evolution of species, and the fossilization process
Taphonomy
the study of what happens to an organism after death
Why is taphonomy important in biological anthropology?
To obtain as much information as possible from the remains of once-living creatures, one must understand the processes that occur after death. It is so important that many scientists have recreated a variety of burial and decay experiments to track taphonomic change in modern contexts. These contexts can then be used to understand the taphonomic patterns seen in the fossil record
What might taphonomic analysis reveal about human culture, or the challenges people faced?
Taphonomic analysis can also give us important insights into the development of complex thought and rituals in human evolution. Taphonomy helped to establish whether these burials were simply the result of natural processes or intentionally constructed by humans. Taphonomic evidence may tell us how our ancestors died.
How old is the Earth?
Earth is roughly 4.6 billion years old, give or take a few hundred million years.
Laetoli footprints
These 70 footprints, now referred to as the Laetoli Footprints, were created when early humans walked in wet volcanic ash in Tanzania
Discovered by Mary Leakey
What type of fossil are the Laetoli footprints, and what species likely made them?
Since they are footprints they are trace fossils and Australopithecus afarensis made them
What special circumstances allowed the Laetoli footprints to be preserved?
Before the impressions were obscured, more volcanic ash and rain fell, sealing the footprints
What are the two categories of fossil dating techniques?
relative dating methods and chronometric sometimes called absolute) dating methods.
relative dating: relies on simple observational skills that approximate time
chronometric dating: provide specific dates and time ranges that are based on work in other disciplines such as chemistry and physics
Law of Superposition
Essentially, superposition tells us that things on the bottom are older than things on the top. It stands to reason that each layer is older than the one immediately on top of it
What is the potassium argon dating technique?
can reach further back into the past than radiocarbon dating. Used to date volcanic rock, these techniques are based on the decay of unstable potassium 40 into argon 40 40Ar) gas, which gets trapped in the crystalline structures of volcanic material.
measuring the ratio of radioactive argon to radioactive potassium in the rock. Basically, the amount of radioactive potassium decreases as argon increases
What is the radiocarbon dating technique?
The leading chronometric method for archaeology is radiocarbon dating. This change occurs at a predictable rate for nearly all radioisotopes of elements, allowing scientists to use unstable isotopes to measure time passage from a few hundred to a few billion years with a large degree of accuracy and precision.
All organisms are made up of a form of an element called isotopes: carbon 12 (six neutrons). Cosmic rays (high energy particles from the solar system) hit the nitrogen particles of carbon 12 changing it to and carbon 14 (eight neturons). When an animal dies, since the carbon 14 is unstable, every 5,730 years, half of the carbon 14 atoms will decay into nitrogen. We can measure the ratio of carbon 12 to carbon 14. Carbon 12 stays the same while carbon 14 decreases over time after an organisms’s death.
Potassium-argon dating is useful because one can use it to date
very old remains
James Hutton’s theory of ____ was crucial to understanding fossils.
Deep Time
Many fossils are found nearby ancient
lakes
The Laetoli footprints provide valuable information about the ____ of early hominins.
bipedality
What is the visual predation hypothesis?
It’s the idea that humans evolved to have 3D and color vision because we were evolved to hunt insects so this is a way to explain why we have these traits.
Matt Carmill-late 1960s and early 1970s
The visual predation hypothesis was unpopular with some anthropologists. One reason for this is that many primates today are not especially predatory.
Who was Gigantopithecus?
One of the most extreme examples of ape robusticity is the Asian hominoid, Gigantopithecus
Known only from teeth and jaws e.g., Figure 8.22), this ape probably weighed as much as 270 kg 595 lbs.) and was likely the largest primate ever
it has been reconstructed as a bamboo specialist, somewhat like the modern panda. Small silica particles phytoliths) from grasses have been found stuck to the molars of Gigantopithecus Ciochon et al. 1990). Recent studies evaluating the carbon isotope composition of the enamel sampled from Gigantopithecus teeth suggest that this ape exploited a wide range of vegetation, including fruits, leaves, roots, and bamboo
Unique traits of primates
the grasping hands and feet of primates are well suited to gripping tree branches of various sizes and our flexible joints are good for reorienting the extremities in many different ways.
the reduced olfactory system, acute vision, and forward- facing eyes of primates are an adaptation to making accurate leaps and bounds through a complex, three-dimensional canopy. The forward orientation of the eyes in primates causes the visual fields to overlap, enhancing depth perception, especially at close range.
NAILS (distinguishing trait), clavicles, placentation, orbits encircled by bone, three tooth types i.e., incisors, canines, premolars/molars), posterior lobe of the brain, calcarine fissure of the brain, opposable thumb and/or big toe, nail on the big toe, well-developed cecum, pendulous penis, testes within a scrotum, and two nipples in the pectoral region.
What were the plesiadapiforms?
Archaic primates
Plesiadapiforms are archaic primates, meaning that they possessed some primate features and lacked others.
The word plesiadapiform means “almost adapiform,” a reference to some similarities between some plesiadapiforms and some adapiforms or adapoids; later-appearing true primates)—mainly in the molar teeth.
Purgatorius is the earliest primate
Dental formula
is a method to characterize how many of the different kinds of teeth are present in the mouth
How does the dental formula of humans differ from apes and other primates?
the typical dental formula is 2:1:2:3. This means that if we divide the mouth into quadrants, each should have two incisors, one canine, two premolars, and three molars. In total that is eight teeth a quadrant, for a total of 32 teeth.
Explain why researchers may never have a complete picture of the types of tools early hominins and primates might have used, and how they used them.
However, the vast majority of tool use in primates and, one can argue, in humans) is not with durable materials like stone.
Why is Sahelanthropus tchadensis an important fossil?
The earliest dated hominin find between 6 mya and 7 mya, based on radiometric dating of volcanic tufts) has been argued to come from Chad and is named Sahelanthropus tchadensis
What aspect of the skull distinguishes between robust australopithecines and grace australopithecines?
This pattern of larger posterior dentition even relative to the incisors and canines), thick enamel, and cranial evidence for large chewing muscles is far more pronounced in a group known as the robust australopithecines, as opposed to their earlier contemporaries or predecessors,
the gracile australopithecines, and certainly larger than those seen in early Homo, which emerges during this time
How were the Oldowan tools made?
the Oldowan, named after the site of Olduvai Gorge where the tools were first
discovered. The time period of the Oldowan is generally considered to last from about 2.5 mya to 1.6 mya.
The rock selected as the core must
be struck by the rock serving as a hammerstone at just the right angle so that one or more flat flakes are removed.This requires selecting rocks that will fracture predictably instead of chunking, as well as the ability to plan ahead and envision the steps needed to create the finished product. The process leaves both the core and the flakes with sharp cutting edges that can be used for a variety of purposes.
Explain why losing body hair and being able to sweat may have given humans an advantage.
Many experts believe that the driving force behind our loss of body hair was the need to effectively cool
ourselves. Along with the lack of hair, humans are also distinguished by being exceptionally sweaty: we sweat
larger quantities and more efficiently than any other primate. Sweating produces liquid on the skin that cools you off as it evaporates
How did cooking food change our skeleton?
During this time, stone tools were becoming increasingly important. If hominins were using these tools to cut up,
tenderize, and process meat and plants, they wouldn’t have to use their teeth so vigorously.
Cooking food could also have contributed to the reduction in tooth and jaw size. Cooking provides a head start in the
digestive process because of how heat begins to break down food before food even enters the body, and it can help the body extract more nutrients out of meat and plant foods such as starchy tubers. Most importantly, it allowed for the larger brain and body size and smaller gut size) seen in Homo erectus.
How were the early members of the genus homo different from the australopithecines?
Homo habilis (earliest genus homo) has a somewhat larger brain size–an average of 650 cubic centimeters cc) compared to less than 500 cc for Australopithecus. Additionally, the skull is more
rounded and the face less prognathic (jaw jutting out). However, the postcranial remains show a body size and proportions similar to Australopithecus.
Which species of hominin was the first to leave Africa?
homo erectus
What type of evidence do we have that humans and Neanderthals interbred?
recent DNA evidence suggests that they at least occasionally interbred.
Geneticists have found traces of Neanderthal DNA 1% to 4%) in modern humans of European and Asian descent that is not present in modern humans from Africa. This is generally interpreted as indicating limited regional interbreeding with Neanderthals.
What is most remarkable about the skeleton of Homo naledi?
This has been perhaps the greatest shock of all about Homo naledi, as this places this fossil as a
contemporary to modern Homo sapiens, despite the very primitive features it retains.
Homo naledi possessed a mixture of traits that are Australopithecus-like (particularly in the pelvis and shoulder) and Homo-like (particularly in the hands and feet, and the size of its brain)
Assimilation model
The Assimilation model proposes that modern Homo sapiens evolved in Africa first and expanded out but also interbred with the archaic Homo sapiens they encountered outside Africa.
What were the Chauvet and Lascaux caves in France known for?
Over a hundred art pieces representing 13
animal species are preserved. Some depicted species are common to European cave art, such as deer and horses. Others are rare, such as rhinos and owls. Two possible human figures are in the deepest gallery of the cave system. At this site, there are over 6,000
painted figures on the walls and ceiling Figure 12.17). The paint was made of a mix of mineral pigments in liquid binder made from fat or clay.
What is most remarkable about the Irhoud skull?
Statistical
comparisons with other human crania concluded that the Irhoud face shapes were typical of recent modern humans while the braincases matched ancient modern humans. Based on the findings of other scientists, the team expected these modern Homo sapiens fossils to be around 200,000 years old. Instead, dating revealed that the cranium had been buried for around 315,000 years.
Together, the modern-looking facial dimensions and the older date changed the interpretation of our species, modern Homo sapiens. Our key evolutionary changes from the archaic Homo sapiens of the previous chapter to our species today happened 100,000 years earlier than what we had thought. In addition, the new information suggests that our home region covered more of the vast African continent instead of being concentrated in the east.
What types of behavior are affiliated with agriculture?
Remaining in one place led to aspects of life that were uncommon in foragers: the construction
of permanent shelters and agricultural infrastructure such as fields and irrigation, plus the development of storage
technology such as pottery to preserve extra resources in case of future instability. Laws influenced the behavior of citizens,
establishing ideal behavior and punishment for deviations. specialization
Modern humans most likely descended from whom?
homo erectus
What was Neanderthal cranial capacity compared to Homo sapiens cranial capacity?
larger than humans
Eugenics
A set of beliefs and practices that involves the controlled seqlective breeding of human populations with the hope of improving their heritable qualities, especially through surgical procedures like sterilization and legal rulings that affect marriage rights for interracial couples.
The Great Chain of Being
Finally, there is also the “Great Chain of Being,” conceived by ancient Greek philosophers like Plato 427‒348 B.C.E.) and Aristotle 384‒322 B.C.E.). They played a key role in laying the foundations of empirical science, whereby observations of everything from animals to humans were noted with the aim of creating taxonomic categories.
What type of environment do we find modern primates today? Where do Lemurs live?
Magagascar
What hunting technology developed during the upper Paleolithic?
Stone tools
What feature of the skull shows us whether an animal was a biped or a quadruped?
the large hole in the back of the skull called the foramen magnum because of how it reflected balance. bipeds have it dead center in comparison to quadrupeds
Biological determinism
The erroneous concept that an individual’s behavioral characteristics are innate and determined by genes, brain size, or other physiological attributes, and with no influence of social learning or the environment around the individual during development.
What is true of humans compared to other primates as well as other animals?
An important fact to bear in mind is that humans are 99.9% identical to one another. This means that the
apportionments of human diversity discussed above only concern that tiny 0.1% of difference that exists between all
humans globally
How could studies of genetic diversity in apes, chimpanzees and humans contribute to greater understanding of disease? How might these studies explain why humans are different than non-human primates?
Genes that may code for genetic susceptibilities to tropical diseases that
affect multiple primates can be studied through genome-wide methods. Species differences in the genomes associated
with speech, behavior, or cognition could tell us more about how human individuals may be affected by genetically derived neurological or speech-related disorders and conditions. Comparative studies of human and nonhuman great ape genetic variation
highlight the complex interactions of population histories, environmental changes, and natural selection between and within species.
Epiphyses
