Midterm 2

Question 1

The adaptation to an arboreal life resulted in many anatomical and behavioral changes for primates. Describe and discuss these.

Answer 1

Foramen magnum position towards center in humans, further back in chimps
Sagittal crest mastication
Upper body: clavicle, rotating forearm
Spinal cord: distinct, flexible
Opposable thumb: precision grip
Many have Hallux: opposable big toe
Enhanced vision: binocular (front face), stereoscopic (depth perception), color, fovea centralis
Reduced smell: lost rhinarium, secondary sense
Enhanced touch: nerve endings, fingernails
Social: adaptive, plastic diet, long life, intelligent, complex social, diverse

Question 2

Identify the five groups of primates. What traits are unique to each group (i.e. could help you identify that group in a zoo or in nature if you lacked a guidebook or signage)? Add where in world

Answer 2

Lemurs+lorises: have rhinarium and snout, dental comb for grooming and claws, less dexterous phalanges, dental form 2133
Tarsiers: head rotates 180, long foot bone can jump 6 feet, nocturnal, carnivorous
New world monkeys: mostly arboreal, Latin America, some have prehensile tails (can grasp), 2133 dental formula, forward facing nostrils, long, curved nails
Includes capuchin, howler monkeys, tamarins, squirrel monkeys
Old world monkeys: terrestrial and arboreal, Africa and Asia, no prehensile tail, sideways facing nostrils, ischial callosities (butt pads), 2123 dental formula, flat nails
Includes baboons, vervets, macaques
Apes: no tail, high intelligence, omnivorous
Small: ischial callosities, less sexual dimorphism, monogamous, Asia, arboreal
Includes siamangs and other gibbons
Great: no ischial callosities, sexual dimorphism depending on species, complex social behavior, non-monogamous, Africa and Asia, terrestrial or arboreal
Includes 5: orangutans, gorillas, chimps, bonobos, humans

Question 3

What are the two biggest threats to primate biodiversity?

Answer 3

Loss of habitat

Poaching: bushmeat trade

Question 4

How do cooperation and long-term relationships benefit a primate individual’s survival? How does cooperation benefit a primate group’s survival?

Answer 4

Grooming, allocare (care for offspring), reduce predation, food acquisition
Group can find more food, defend against predators, have more kids

Question 5

Primates are social animals. What are some advantages of living in groups? Development of long-term relationships between social group members?

Answer 5

Living in groups allows cooperative hunting, the sharing of knowledge, protection from predators, aid in child-rearing. Long-term relationships allow specialization of roles, and coupling-up for child-rearing.

Question 6

Primatologists have identified 6 residency patterns among primate species. Create a table that
lists and defines each type of pattern, describes any key features relating to competition and/or
reproductive success, and provides an example species.

Answer 6

Polygynous
One male, many females
Sexual dimorphism
Gorillas

Polyandrous
One female, many males
Rare
Marmosets

Multiple males and females
Sexual promiscuity
Low competition, little sexual dimorphism
Bonobos

Bachelor groups
Groups of males
temporary , coexist with other residence patterns, predator control
Baboons

Monogamous
One male, one female
Reproductive success tied to partner, male invests heavily in offspring
Gibbons

Solitary
Adults interact mainly for sex
High sexual dimorphism, unsuccessful males even more solitary
Orangutans

Question 7

How do male and female primates differ in their competition? How do these differences affect
behavior or physical morphology?

Answer 7

Males want access to females, are bigger, big canines, aggressive, vocalization, sometimes infanticide
Females: access to food for offspring, social hierarchy

Question 8

List the 3 factors that affect successful food acquisition and discuss how these factors impact species’ food choices and primate distributions globally, as well as across the landscape.

Answer 8

Quality: calorie energy, nutrition, digestibility
Distribution: food is distributed in patches throughout the landscape. Adjust where primates live based on where the food is.
Availability/access: food may not be available in certain seasons, or present but unavailable due to other reasons

Question 9

Why do primates, including humans, vocalize?

Answer 9

Indicate emotional state, mediate social encounters, share info about surroundings, name resources, separated from group, alarm calls

Question 10

Explain why communication, symbolic or vocal, is key to primate survival.

Answer 10

Communication allows the transmission of knowledge, alerting of danger, mating calls, indicating emotional state, and generally locating other members of the group.

Question 11

Discuss the three ways to define a species. How might differences in these definitions be important for understanding the evolution of our ancestral hominid line?

Answer 11

Biological definition: Populations with a shared, closed gene pool under natural conditions
Morphological definition: Populations/Groups of organisms that share physical features (impt. for fossils)
Genetic definition: Populations/Clusters of organisms that share genes (impt. for asexual reproducers or those lacking shared morphology)

Question 12

List 6 ways that keep organisms within the same gene pool for producing offspring. Give a primate/human example for each.

Answer 12

Nature’s Rules for Producing Offspring
Occupy the same territory
Both be fertile at the same time
Use appropriate signaling – pheromones, mating calls, courtship rituals, behaviors, visual stimuli
Be attractive to potential partner
Have appropriate equipment – penis shaped to fit vagina
Match physiology and genetic system of potential partner – pH, DNA, etc.

Question 13

Many primates exhibit sexual dimorphism, including gorillas, orangutans, baboons, and humans. How does female primate mate choice drive this selection?

Answer 13

They want to be with the individual who will provide them the strongest and healthiest offspring. Therefore there is competition between males for females.

Question 14

How does extinction influence speciation?

Answer 14

The extinction of one line may provide an opening for the adaptive radiation of another. In the case of mammals, for instance, the extinction of large reptiles allowed mammals to increase their range dramatically, and grow in size, finding many different niches which slowly became new species.

Question 15

Compare background and mass extinction.

Answer 15

Background: organism death rate is higher than birth rate, happens slowly, ex is being outcompeted for food by different species
Mass: near simultaneous loss of many lineages, takes a couple of hundred years, we are currently on the 6th

Question 16

What has to happen for an organism to become a fossil?

Answer 16

1: die in a good location to be preserved like river or lakebed
2: soft tissues decay, hard (bone) material left
3: sediments deposited on remains, like mud and volcanic ash
4: minerals in H2O replace Calcium and Phosphorus
5: deposit weight forces out H2O and air, rock hardens
6: uplifting and erosion exposes fossil

Question 17

What is NAGPRA, and why is is important to archaeologists?

Answer 17

NAGPRA is the Native American Graves Protection Repaciation and Act, passed in 1990. It requires a very specific process for returning unearthed Native American remains to descendents, tribes, and organizations. It only applies to Native Americans.

Question 18

What is the meaning of the “half–life” of Carbon 14? (also check the video posted to the module page)

Answer 18

Half-life is the time after which the radioactivity of a molecule is reduced by half. This allows the time since the formation of a molecule to be estimated relatively accurately. Because Carbon 14 is relatively stable, it is useful for getting time estimates from a long time ago.

Question 19

Choose two types of relative dating, and describe the process involved.

Answer 19

Stratigraphy - From which layer of earth the fossil was found in. Generally, lower equals older.
Fluorine dating - Generally, a bone has more fluorine in it the longer it was underground.
Palynology - From pollen in/on fossil. When was this plant around?

Question 20

When paleoanthropologists compare hominid and non-human primate fossils they must consider whether the variation they observe is between individuals of the same species or between individuals of different species. What are 7 sources of potential variation they must consider?

Answer 20

1: different ages/maturity
2: sexual dimorphism
3: time and temporal variation, like if their growth is stunted
4: adapted to geographic location
5: normal range of variation within population, like muscle size can change skeleton
6: abnormal variation within population, like an injury or genetic disorder
7: geological process deformation

Question 21

How is the fossil record limited?

Answer 21

Representation of species
Denisovans rare
Neanderthal/Denisovan hybrids
Lack of hard material
Conditions for preservation
Congo river basin has none since its a rainforest
Location
Haven’t looked everywhere possible
Wars and conflicts
Can’t reach
Money
Lost like with sinking ships
Time sequence available
Land changes over time

Question 22

Why is it important to reconstruct ancient environments? What are some sources of information and what can they tell us?

Answer 22

Skeletal form: habitat, temperature, other species
Teeth: diet, other species; gritty food can wear down teeth, different animals can suggest different environments
Climate: especially temperature; ice cores, phytoplankton; know Africa was drier when we became bipedal
C4 and C3 plants: diet and habitat reconstruction
C3: woody plants like trees
C4: grass, cacti
Association with teeth
Soils: habitat, carbon isotope ratios

Question 23

The methods used to date archaeological or fossil remains are varied. Why are there so many different ways to conduct dating analyses? Use examples in your answer.

Answer 23

Not all methods work for each set of remains, if only relative dating works then it is helpful to cross check multiple methods
Ex: dendrochronology can only be used for trees
Ex: can cross check stratigraphy with pollen samples

Question 24

(a) Define the Law of Superposition. (b) Then, using this image, explain how an archaeologist would utilize relative dating and the law of superposition to describe and date two artifact types from two separate stratums. (c) Finally, choose one stratum and utilize the artifacts to briefly describe the group that occupied the site during that particular period of time.

Answer 24

The Law of Superposition asserts that the layers of earth further below the surface, and thus the objects found in them, are older than those closer to the surface. An archaeologist might find two sets of primate fossils, one not far below the surface, and one two distinct layers of material type below that. Immediately, the archaeologist would assume the lower fossils were older. Palynology could cross-check this by seeing which plant pollens are present in the same layers. Let’s say the lower set is found in a strat associated with the Oligocene epoch. Because this is when anthropoids proliferated, this would lend extra significance to any primate fossils suggesting bipedalism, increased brain size, or decreased chewing apparatus. If there are any sharp rocks in the same layer, this may also be interpreted as very early tool use, changing the narrative of tool development.

Question 25

Compare the angiosperm radiation, arboreal hypothesis, and the visual predation hypothesis as theories for primate evolution.

Answer 25

Arboreal: adapted to tree life; depth perception, grasping hands and feet, intelligent, sense of smell weaker Visual predation: adapted to hunt insects and small animals in trees; criticism is that other tree animals are not related to us Angiosperm radiation: response to availability of fruits and flowers, follow the spread of angiosperms; criticism is that trees appeared before humans

Question 26

What is the name of the earliest Primate group that flourished following the extinction of the dinosaurs in the late Paleocene?

Answer 26

Plesiadapiforms

Question 27

Describe the Eocene environment for early primates.

Answer 27

Hot, wet, tropical climate

Question 28

During the Oligocene, what type of primates existed? Describe the environment and their characteristics.

Answer 28

Environment -hot, wet, tropical climate

Question 29

What is the relationship between climate shifts and the emergence of the earliest primates? Present each of the epochs (Paleocene, Eocene, Oligocene, and Miocene), and explain the evolution of the primates from a reptilian beginning to the emergence of the first apes.

Answer 29

Paleocene: Starts 65 mya, global temperatures cool due to Yucatan meteor impact, dinosaurs (cold-blooded) die off, tiny plesiadapiforms (warm-blooded) proliferate Eocene: Starts 55 mya, global temperatures warm suddenly, giving rise to first definite primates, prosimians, which thrived in rainforests through N America, Africa, Eurasia. Sudden temperature dip towards end, killing of N American primates, and generally reducing their range. Oligocene: Starts 34 mya, grasslands & some forests. Primates diversified and expanded range. Many species have mix of monkey & ape features. Aegyptopithecus has big brain for time, large visual cortex. Primates arrive in Central & South America from Africa, likely by rafting from powerful Congo River. Miocene: Starts 23 mya, open woodlands to tropical forest. Proconsuls, the first apes, found on Lake Victoria Islands in Africa. Chororapithecus abyssinicus, ancestral to gorilla, also found in present day Ethiopia. Evidence for early bipedalism.

Question 30

Scientists have hypothesized at least 4 separate origins for New World Monkeys. Choose two of the most plausible, briefly describe what they are and any supporting evidence.

Answer 30

Congo river in Africa pushed raft to South America, continents were close Migrated south from Africa to Antarctica to South America by rafting, continents were close though it’s less likely than previous

Question 31

Proconsul, dated to the early Miocene 17-21 mya, is a strong contender for the missing link between monkeys and apes. Briefly describe its features and identify which are more monkeylike and which are more apelike.

Answer 31

Upper body generally ape-like, w/ limited wrist mobility, ape-like jaw and teeth, ape-sized toes, no tail, but otherwise monkey-like lower body.

Question 32

No ape fossils have been found in Europe or Asia prior to 17 mya, the early Miocene. Then there is an explosion of species on these continents, despite few fossils found from the same time period in Africa. Then ape species begin to go extinct in Europe and Asia, while new species arise in Africa. Provide a potential explanation for these continental differences in speciation and extinction based on the existing evidence.

Answer 32

In the early Miocene, African and Eurasian land masses had not yet made contact. This suggests that apes evolved in Africa, then crossed to Eurasia. Changes to climate and food access. Primates moved out of Africa. Extinctions in Asia and Africa were associated with climate change (climate became dryer and cooler).

Question 33

What are 3 obligate early hominid characteristics? When did they appear?

Answer 33

``` Bipedalism Lose large, projecting canines Material culture Hyoid bone evolution allows speech Cooperative hunting with tools, long-distances Domestication ```

Question 34

List 5 skeletal characteristics of bipedalism and describe why they are advantageous to bipedalism.

Answer 34

Foramen magnum: weight shifts under skull and stand up straighter Pelvis shortened front to back, less hunched over Long legs: more energy efficient to move Double arched foot: both bottom and across the top, less painful to walk Lost opposable big toe: easier to walk flat on feet

Question 35

How does hominid mastication differ from that of the other apes? Think about tooth shape, masticular muscle, tooth enamel, and foods.

Answer 35

Hominids have small teeth, especially canines, and comparatively thick enamel. The masticular muscle is comparatively small, and there is no sagittal crest. Chew vertically while apes chew horizontally. Dental pattern:

Question 36

Briefly describe the 3 hypotheses for why hominids emerged as a species line about 5-8 mya.

Answer 36

Darwin’s hunting: Bipedalism freed hands to carry weapons Need high intelligence to make tools No need for big canines if have tools Criticism: didn’t know that chimps use tools Patchy forest/savanna: Forests got patchy when East Africa became drier and colder Food more dispersed, walking made it easier to reach/carry food Strong evidence Provisioning: Monogamous dads increase reproductive success by providing food and protection to mom and kids More cooperation of males, less sexual dimorphism; fossil evidence Require monogamous bonding Evidence thin: would need behavior observation

Question 37

Compare advantages and disadvantages of bipedalism.

Answer 37

Advantages: Efficient long-distance travel, less sun exposure, ability to see longer distances, ability to carry objects/children Disadvantages: Easier for predators to spot, slower sprinting

Question 38

Name four anatomical changes that occurred in the human species to accommodate bipedalism. In other words, how is it “written on our skeletal bodies”?

Answer 38

Pelvis shortened front to back Foramen magnum positioned under skull Lost opposable big toe Long legs compared to arms

Question 39

What sorts of environments did pre-Australopithecines live in? How would this affect their locomotion?

Answer 39

Savannahs, wetlands, woodlands. Possess arboreal characteristics, opposable toe, curved phalanges that help with gripping branches, still have ability to walk bipedally.

Question 40

What sorts of environments did pre-Australopithecines live in? How would this affect their locomotion?

Answer 40

Woodlands & forests. Moving efficiently across the ground efficiently, ala bipedalism, would be less useful than brachiation, so primates from this era would likely have curved hands and feet, halluxes, longer pelvises, long arm:leg ratio, and knuckle or palm walk.

Question 41

Why is Australopithecus afarensis (Lucy) an important find?

Answer 41

First evidence of bipedalism

Question 42

What are Oldowan pebble tools and for what were they used? Who used them?

Answer 42

Oldest known stone tools Choppers: stone cores with flakes removed from part of surface chopping, cutting and scraping Australopithecus Garhi

Question 43

What were the major morphological changes to pre-Australopithecines, Australopithecines, and Homo spp.?

Answer 43

pre-Australopithecines: Binocular vision. Brain growth. Australopithecines: Further brain growth. H. sapiens: Further brain growth.

Question 44

What is the law of competitive exclusion, and what role did it play in early human evolution?

Answer 44

When two similar species rely on the same resource, one will go extinct. This explains the remainder of only one species of the genus Homo, and some paleoanthropologists believe it may explain the loss of most large carnivores after H. erectus cooperative hunting emerged.

Question 45

What are the 5 obligate features of Homo spp.? (and 6 features of anatomically modern humans?)

Answer 45

``` Homo: Bipedalism Non-honing chewing Material culture Hyoid Cooperative hunting AMH: Domestication of doggos ```

Question 46

Define the obstetrical dilemma and describe some of the adaptations that have evolved to solve this dilemma.

Answer 46

Problem: bipedalism requires narrow, bony birth canal but increased intelligence means a bigger skull Social Adaptation: birth assistance Genetic Adaptations: Sex differences in pelvis: men are more narrow so faster locomotion Shortened gestation Relaxin hormone: before birth it softens all ligaments and joints to open pelvis more Rotate in birth canal: head first, face down Broadened pelvis: bowl shaped, 1st in Homo erectus Unfused skull in newborns: soft spot

Question 47

What 3 major developments led to better nutrition, height increases, and brain size increase? In which species did these occur?

Answer 47

Control over fire Production of Acheulilan tools Cooperative hunting

Question 48

How do Acheulian complex tools differ from Oldowan pebble tools?

Answer 48

Achuelian complex tools added is characterized by a distinctive hand axe, with a point at one end and cutting edge all the way around. It became standardized and added new materials later on.

Question 49

Recent studies of large carnivore fossils from Africa have led to a new hypothesis about why there was a major decline in species diversity 2 mya. What is this new hypothesis? What sorts of observations did the scientists use from the fossils records to generate this hypothesis?

Answer 49

Homo erectus use of tools and cooperative hunting led them to outcompete large carnivores for food, trigger ecological disruption of savanna ecosystem

Question 50

H. erectus migrated out of Africa and into Asia and Europe. Interesting finds have been found on all three continents. Choose 2 of these finds, give a brief description and tell me why they are interesting to our study of the hominin line and/or humanity.

Answer 50

Evidence for compassion: Dmansi man had no teeth and had to have his food prechewed for him Large increase in brain size: potential for deeper thoughts

Question 51

How does Bergman’s rule apply to understanding Neandertal remains and adaptation?

Answer 51

Because Neadertals had a high volume:surface area ratio in the torso, it seems likely that they lived in and were adapted for a cold climate.

Question 52

Many Neandertals lived in Europe during a glacial period. What sorts of adaptations for a cold, high latitude climate do we see in their skeletal remains that would lead some paleoanthropologists to suggest Neandertals were hyper-arctic adapted?

Answer 52

Big noses: warm air so it doesn’t freeze their brains Occipital bun: muscle attachment to support large face Build: short, stocky, heavy, muscular; easier to stay warm and pump blood around the body At least some had fair skin and hair

Question 53

Neandertals heavily muscled bodies required a lot of calories to power in Europe’s glacial climate. What sorts of foods did they eat to get those calories? What special tools or hunting/foraging methods to get those calories did Neandertals develop

Answer 53

Lots of meat, some plants though Levenois technology Hunt up close to prey

Question 54

What evidence for Neandertal culture exists? What can it tell us?

Answer 54

Similar hyoid to humans, could speak Family groups found together Had formal burials, carefully arranged bodies Symbolic: body decor with paint, jewelry, musi

Question 55

What evidence for Neandertal behavior (altruism, compassion, care for dead, etc.) exists? What can it tell us?

Answer 55

Carefully arranged bodies in graves with flower pollen and animal bones on them tells they valued and mourned their dead Evidence of sick and injured people living longer because others helped them, and some form of healthcare

Question 56

Neandertals ranged across Europe and Asia from 300,000 to 30,000 years ago. Diverse types of evidence suggest that in many ways they were just like us. Using evidence discuss what we know of their physical appearance, tool production, symbolic life, language, altruism and compassion, and how they accessed food.

Answer 56

They had big noses, which were likely used to filter and heat cold, dusty air. They had occipital buns, which attached to the large muscles required for their big faces. Larger brain capacity than AMH. They were shorter, but muscular and robust, likely due to the cold climate. We have possible evidence that they made flutes from bone, and evidence of ochre and charcoal cave paintings, ochre jewelry. Culturally, we have evidence due to families found together of patrilocal family living, long inter-birth intervals, and burials due to seeming deliberate arrangement of body and flower pollen. They had hyoids similar to AMH, suggesting that they could speak. Worn teeth suggest that they used them as tools. First to make tools from bone. Hunting was important, but plant starch has been found on their teeth. Group hunters, likely close-up to animal due to quantity of broken bones, w/ little sexual dimorphism.

Question 57

Describe 2 hypotheses for why Neandertals went extinct.

Answer 57

Violent contact with Homo sapiens, we had bigger population so won Competitive replacement: we had better technology and dogs for hunting

Question 58

How do we know that Neandertals and Denisovans interbred with anatomically modern H. sapiens? Briefly described two contributions of Neandertals and two from Denisovans that contributed to our survival as a species and our phenotype?

Answer 58

2-4% neanderthal DNA modern humans, not in sub-saharan africa Hyper coagulation of blood: blood clots faster, good if injuried during hunting Actinic keratosis: sun exposure causes skin flaking 4-6% denisovan DNA melanesians, fiji, philippines australia and papua new guinea, tibetans Tibetans: adapted for high altitudes Melanesians: dark skin, brown hair and eyes .2% denisovan DNA in mainland asia and native americans

Question 59

Define island dwarfism. What environmental and morphological evidence suggests that Homo floresiensis and Homo luzonensis be product of island dwarfism?

Answer 59

Definition: long term isolation leads to smaller stature from limited food sources and a lack of predators Floresiensis: very small, half the size of human female, lived on a tiny island Luzonensis: small teeth, suggests smaller skull, isolated island

Question 60

Briefly describe why H. floresiensis and H. luzonensis important for understanding hominin evolution?

Answer 60

Floresiensis: coexisted with modern humans May have contributed to modern human DNA Another branch of human evolution