evo. lecture 5

Question 1

Rise of the Genus Homo

Answer 1

• earliest evolved in Africa.
• most date 2.4 to 1.8 MYA.
• first fossil member of taxon: Homo habilis, which means “Handy man”.
• the idea back then was that only humans used tools
• some researchers suggest that H. habilis is “junk taxon” and that there may be two or more species of Homo by 2.0 MYA.
• Human evolution is about branches and not about missing links
• Hominins evolved in Africa, and H. sapiens characterized by bipedalism, expansion in brain size, and changes in dental/cranial features; these changes are on-going
• Complex patterns of human biogeography and phylogenetics
• We are continuing to respond to selective pressures

Question 2

Species in the Genus Homo

Answer 2

• Homo habilis
• Homo rudolfensis
• Homo erectus
• Homo ergaster
• Homo heidelbergensis
• Homo antecessor
• Homo neanderthalensis
• Homo naledi
• Homo floresiensis
• Homo sapiens

Question 3

Medical Anthropology

Answer 3

a

Question 4

Forensic Anthropology

Answer 4

a

Question 5

Homo habilis

Answer 5

• From sites in Tanzania, Kenya, and Ethiopia (2.3-1.6MYA)
• Species designation: brain size and association with stone tools
• Skeletal morphology similar to contemporaneous australopithecines
• First species of Homo or junk taxon?
• May represent two or more different species (H. rudolfensis and H. habilis)

Question 6

Homo rudolfensis

Answer 6

• Koobi Fora, Kenya
• Originally considered H. habilis
• H. rudolfensis or H. habilis first representative of our genus?
• Very controversial
• We don’t know a lot about the first few parts of our cladistics

Question 7

Homo erectus

Answer 7

• First species in genus Homo found outside Africa (Asia and Southeast Asia)
  
  • Evolved and somehow transitioned out of their tropical environment
• 1.8YS-27KYA
• brain and body size changes in lineage
• controlled use of fire and hunting
  
  • the question of scavenging versus hunting is contentious
  • they were able to gather, store, and eat large game
• early African specimens may be different species, Homo ergaster
• general consensus that the earliest specimens found in Africa belong to their own species

Question 8

Homo ergaster

Answer 8

• east and south Africa
• 1.8-1.3MYA
• distinguished from H. erectus by its thinner skull-bones and lack of an obviously supraorbital foramen
• debate on H. erectus or H. ergaster as direct ancestor of modern humans
• still have large, powerful-looking faces; large brow ridges, flat nose, powerful jaw

Turkana Boy

• 7-16 years old
• about 1.6m in height
• brain size: 880cc, likely 910cc at adulthood
• very large compared to the predecessors

Question 9

Homo heidelbergensis

Answer 9

• Europe and Africa
• 700-130KYA
• compared to H. erectus and H. heidelbergensis: decreased dentition, and increased body and brain size
• continues the evolutionary selective pressures, pushing for larger brain and body size
• this means we’re using less of our teeth as a tool (or weapon), but our energetic cost is increasing (with body size and brains)
• selection against being powerful and small

Question 10

Homo antecessor

Answer 10

• Spain
• 1.2MYA-800KYA
• controversy surrounding species designation
  
  • type specimen is juvenile—we don’t know what they’re going to look like when they’re adults
• first hominin in Europe?
  
  • We may have sites that H. erectus used in Europe, but no fossils

Question 11

Homo neanderthalensis

Answer 11

• Europe and middle east (300-35KYA)
• Buried people in graves with “offerings”
  
  • We have an enormous amount of material because they were preserved quite well
• Limb bones heavily marked by muscular attachments; thick walls of cortical bone and large joints
• Neanderthals are extremely muscular, highly active, and athletic by modern human standards
• Largest overall cranial capacity of any hominins—their brain capacity was even larger than that of humans
• Incredibly complex stone tools
• Did they contribute to the gene pool of modern humans?

Question 12

Homo naledi

Answer 12

• Discovered in 2013 in south Africa
• Not dated as of yet
• Body mass and stature—small-bodied human populations
• Endrocranial volume was small, similar to Australopithecus
• Skull shape is like early homo species
• So, skeleton combines primitive features in australopithecines with features known from hominids

Question 13

Homo floresiensis

Answer 13

• Flores Island, Indonesia
• 95-13KYA
• small body size
• small brain size
• primitive and derived features
• not aberrant individual; rather, unique species

Question 14

Homo sapiens

Answer 14

• 160KYA in Africa, 100KYA in Middle East, 40KYA in Europe
• controlled use of fire
• hunting and gathering
• cultural remains, including increasingly complex stone tools
• we have had one of the shortest longevities of any member of our genus
• why us?
• Did we hunt and cause extinction in our own genus?

Question 15

Genetics of Homo neanderthalensis

Answer 15

• Geneticists able to extract DNA from three Neanderthal specimens
• Early studies: genetics of Neanderthals versus modern humans point to a 706KYA separation and considerable genetic variation
  
  • But they had to make new methods to test DNA for dead specimens to protect it from our human DNA
• Recent studies have solved all of the Neanderthal genome
• Demonstrated a range of genetic contribution to non-African modern humans

Question 16

Race

Answer 16

• race: geographically circumscribed population or set of populations that differ from all other populations of a species.
  
  • ​definition used in science.
• subspecies: geographically isolated populations within species.
  
  • ​definition specific to biology.​​
• No biological or phylogenetic ways to define human races
• Race concepts based on everything from skin color through region(s) or origin to ethnicity
• Crude classification system typically involves self-identification based on up-bringing, culture, ethnicity, etc.
• Morphological and genetic differences in human “races” much smaller than those needed to consider nonhuman animals subspecies

Question 17

Skin Colour Adaptation | Race Concept

Answer 17

• Physical traits we think of as clustering together among particular peoples often have much broader distributions
• They continue well outside of geographic areas in which “race” is stereotypically supposed to exist
• skin coloration is largely due to natural selection rather than recent shared descent.

Question 18

Medical Anthropology

Answer 18

subfield of anthropology that draws upon social, cultural, biological, and linguistic anthropology to better understand those factors which influence health and well being (broadly defined), the experience and distribution of illness, the prevention and treatment of sickness, healing processes, and the social relations or therapy management, and the cultural importance and utilization of pluralistic medical systems.

Question 19

Infectious and Chronic Diseases | Medical Anthropology

Answer 19

• infectious disease: caused by microbial agent
  
  • death rates by infectious disease between developed countries (low) and developing countries (high)
  • pandemics—with globalization we’re spreading microbial agents through our food, persons, and everything else
  • co-evolution of humans and pathogens
• chronic disease: non-reversible pathology
  
  • for example, heart disease
  • “wear and tear” on body
  • comparison of death rates by chronic disease between developed (high) and developing countries (low)

Question 20

Malnutrition and Obesity | Medical Anthropology

Answer 20

• malnutrition crsis
  
  • developing nations
  • protein malnutrition
  • micronutrient malnutrition
• obesity crisis
  
  • developed nations; complex causes

Question 21

Forensic Anthropology

Answer 21

• is “applied” science
• borrows methods and techniques developed from skeletal biology, osteology, and anatomy; and applies them to cases of forensic importance
• forensic means “legal”
• methods and techniques to assess: age, sex, stature, trauma, and pathology to help anthropologists understand different populations living all over the world at different times throughout history

Question 22

Age in Skeletons | Forensic Anthropology

Answer 22

• younger individual is, more accurately their age can be estimated
• because process of ossification proceeds more rapidly at earlier ages, and there are more developing bones to examine
• once an individual is more sexually mature, only ranges can be used

Question 23

Sex in Skeletons | Forensic Anthropology

Answer 23

• pronounced difference in shape of pelvis
• birth canal larger and rounder in females
• males have narrower pelves, with smaller and less rounded birth canals

Question 24

Stature in Skeletons | Forensic Anthropology

Answer 24

• sexual dimorphism: males are about 15% bigger than females; difference in size is seen in every bone of the body
• males continue growing longer than females do, by time people reach age 20 females are nearly two years ahead of males in bone development
• measure the length of femur and humerus to determine height

Question 25

Trauma in Skeletons | Forensic Anthropology

Answer 25

• lesion (pathologically produced feature of a bone; such as TB) vs. bone defect (hole, break, or other traumatic damage)
• overall nature of bone defect, timing of trauma relative to death
• pre-mortem
• post-mortem are more confusing

Question 26

Pathology in Skeletons | Forensic Anthropology

Answer 26

• abnormality that arises from disease, malnutrition, or genetic defect
• differs from trauma in that pathology is not normally result of an injury