Major issuesTermsAty 253 1st EditionFinal Exam Study GuideMajor issues What do we mean by “placing a fossil in its context,” and why is this critical to understanding evolutionary processes? This is determining things about it, such as how old the fossil is, and what its environment was like. How do fossils form, and why is taphonomy important to consider in fossilization? They form as a rapid burial occurs after death, and if there is a low oxygen or oxygen-free environment. Taphonomy is what happens to an organism from the time it dies to the time it is discovered. This is important because it cantell us what kind of conditions the fossil went through over the many years before its discovery. What is the difference between relative and absolute dating? Relative: designating an event or object older or younger than another. Absolute (Numerical): designating a date for an event or object in numerical time. How does stratigraphy work? This is how sediments are laid down in successive layers (strata). They are laid down flat, with the bottom layers being older than the top ones. How does radiometric dating work, and what are some examples of the technique? It is the clock-like decay of one isotope into another over time. “Carbon-14” dating is when the isotope Carbon-14 decays into Nitrogen-14. Its half-life is 5,730 years. “Potassium-Argon dating” is when Potassium-14 decays into Argon-14. Its half-life is 1.3 billion years. What are some of the major changes that the earth has experienced in the past? Sea level and temperature, told through oxygen isotopes. What processes may have led to the evolution of primates? The warming of the earth and the spread of tropical forests during the Eocene epoch. What’s so interesting about the Fayum Depression in Egypt? There were over 1,000 anthropoid fossils found, including Aegyptopithecus and other ape ancestors with 2.1.2.3 dental formula.What is a “dental ape”? They have bunodont, Y-5 molars, but lack mobile shoulder joints of suspensory apes. What characteristics do paleoanthropologists look for when trying to identify the first hominins? Increased brain size, smaller face and less prognathism, use of stone tools, and increased reliance on culture. Be familiar with the anatomical features unique to habitual bipedalism. What are the advantages and disadvantages of this mode of locomotion? Advantages: efficient for long distances, frees the hands for carrying things, see greater distances. Disadvantages: greater stress on hips, lower back, and feet; gettingblood up to the brain is harder, birth canal restrictions, it’s slow, injuries can disable an individual. Lucy’s species (what is the species name??), is often described as “part ape, part human.” What characteristics justify such a description? Australopithecus afarensis; bipedal but comfy in trees, ape-like chest (funnel), curved fingers, more sexual dimorphism, bigger intermembral index, chimp-sized brain.What key characteristics arise in H. habilis (in other words, why is this species the first to have our genus name, Homo)? “Skilled human” or “handyman”  use of hammer stone to open up meat as a new dietary possibility (brain started to get bigger with protein?); easier for humans to digest, because it doesn’t take up as much energy. When and where do the first stone tools appear? Why is this invention so important in human evolution? First seen 2.6-2.5 mya  “Oldowan” Discuss the importance of Olduvai Gorge to understanding the earliest archaeological sites and thus the behavior of Homo habilis. What sorts of activities do the concentrations of animal bones and stone tools at these early sites likely represent? The sites had stone tools. animal bones, and hominin fossils from around 2 mya; there were butchery marks on some of the bones, which suggest a transfer to a diet of meat eating. What was the first hominin species to leave Africa? Homo erectus. Describe Homo erectus in terms of anatomy & behavior. About how long ago did H. erectus first colonize the various regions of the Old World? Why is Dmanisi such an important site and what does ittell us about H. erectus? Homo erectus (“upright human”) lived from 1.8 mya to 300,000 years ago. H. erectus used Acheulean stone tools like the hand axe. It had a barrel-shaped thorax, a pronounced brow ridge, postorbital constriction, and a low, sloping forehead. Five separate crania were discoveredat Dmanisi, and found variation within the population of Homo erectus.What does the Acheulean tell us about the mental skills of H. erectus? They had a “mental template,” cognitive development that Homo habilis did not have. Why is the invention of cooking so important in human evolution? It softened food, therefore not making use of large, sharp teeth. It also detoxified plants and made indigestible nutrients available. How does the “Expensive Tissue Hypothesis” account for the evolution of H. erectus with its bigger brain?The theory is that 7% of our body mass is out major organs, but they take 70% of our energy; if one thingincreases, the other must decrease. When H. erectus “took away” from their guts for bigger brains, the barrel thorax evolved. Describe the distinctive anatomy of the Neandertals. Some had red hair and blue eyes. They had stocky trunks, short limbs, and were on average 5 ft 6 in. They had extremely powerful bodies that required massive amounts of energy, and had modern human-sized brains. Describe what we know about Neandertal culture (e.g., speech, burial practices, etc.). They buried their dead, but had no grave goods put in. They probably spoke, as is evident by their hyoid bone looking very similar to humans’. There isn’t much evidence for ritual and symbolic behavior, but they were expert hunters and cannibals. What makes a modern human “modern”? Think in terms of both anatomy & behavior. Vertical forehead, little to no brow ridges, a chin, and an overall puny skeleton. They developed new ways of getting food like fish, fowl, and small game (broad spectrum diet) with highly specialized tools and weapons, such as harpoons, needles, and barbs. There were variations in “style” depending on the regions. Long distance trade and interaction occurred, and tool kits reflect activities and cultures across space and time. When (and where) do we see the first evidence for modern anatomy & behavior? Africa 75,000 years ago:pierced shells.What is