Biology notes for Test #2
Chapter 10- From Hominoid to Hominin
6 million years ago, climate, geographic change led to the evolution of
hominins: cooling, less rain, rain seasonality, woodland and savanna spread
Hominae- clade containing gorillas, chimps and humans
What it takes to be a Biped: skull (position of foramen magnum determines
if something walks on 2 or 4 legs), spine (lumbar lordosis), pelvis is short
and stout, pelvis abductor mechanism (balance), femur (long femoral neck
and cortical bone distribution (nonuniformly), bicondylar angle of the knee
(balance), foot and ankle have a none grasping big toe and arches.
Between 7 to 5 mya, the common ancestor of chimps and humans roamed
At the Beginning, some of the ancestors of humans:
1. Sahelanthropus was found in Chad, Africa and was dated at about 6-7
million years old. Features: foramen magnum suggests bipedality,
chimpanzee-sized brain, small canines, flat face and large browridge.
2. Orrorin was found in Kenya, Africa and was dated to be about 6 million
years old. Mix of woodland and savanna habitat, femur suggests
bipedality and teeth are chimpanzeelike.
3. Ardipithecus kadabba was found in Ethiopa, Africa and was dated to be
about 5.2-5.8 million years old. Features: toe bone suggests bipedality,
canine sharpens against lower premolar.
4. Ardipithecus ramidus was found in Ethiopa, Africa and was dated to be
about 4.4 million years old. Woodland habitat, bipedal based on the
features of his skull, pelvis and foot. Climbing is based on hand, feet
and pelvis; as well as a small brain and small canines.
Many different hypotheses as to why hominines have evolved to walk on
Additional species of human decent:
1. Australopithecus anamensis- Found in Kenya and Ethiopia of Africa and was
dated to be about 3.9-4.2 million years old. Habitat in a grassy woodland environment, bipedal (tibia bone) and canines are smaller than modern
2. Australopithecus afarensis- Found in Ethiopia, Tanzania and was dated to
be about 3-3.6 million years old. Habitat in a woody grassland; contained
smaller canines, larger molars than Au. anamensis, bipedal, partial skeleton
of Lucy (actual specimen) and the body size is of dimorphism.
3. Australopithecus africanus- Found in South Africa, cave deposits; was dated
to be about 2.2-3 million years old. Habitat was in the woody grassland and
some of its bony features were: cranially similar to Au. afarensis, bigger
molars and smaller canines. Also was bipedal and had rapid tooth
4. Australopithecus garhi- Found in East Africa, was dated to about 2.5 mya
and its bony features were: a small brain, sagittal crest, large teeth, possibly
longer legs and possibly had stone tools.
5. Australopithecus sediba- found in the Malapa Cave in South Africa, being
dated from about 1.8-2 mya; bony features are: small brain, small teeth,
long arms, primitive foot as well as derived pelvis and hands.
6. Paranthropus boisei- The Robust Australopiths- cranial adaptations=
enormous back teeth, sagittal crests, large temporalis muscles, huge cheek
bones (zygomatic arches) and was bipedal. Was dated to be from about 2.5
mya in Kenya, Tanzania and Ethiopia. Also they ate seeds, tubers and roots.
7. Paranthropus robustus- found in South Africa from about 1-1.8 mya;
contained cranial and dental adaptations for heavy chewing, bipedal and
extended growth in males.
8. Paranthropus aethiopicus- found in Kenya from about 2.5 mya
9. Kenyanthropus- found in Kenya from about 3.2-3.5 mya and contained
many features such as: small bones, flat face and small molars.
What are the differences from phylogenetic trees that we have
encountered before? Answer: scale, a lot of question marks, dashed lines,
Homo heidelbergensis (usually marked with a node= common ancestor is
unknown). Chapter 11- Oldowan Toolmakers and the Origins of Human Life History
The Origins of Tool Use- tools found within the environment, using tools is
ancient in our lineage (many modes of tool use)
The Oldowan Toolmakers- flakes, hammer stones and cores used to create
tools (mostly made by a right handed individual). Earliest evidence of this is
from Dikika from about 3.4 mya as well as Gona (first tool made) from 2.5
Complex Foraging Strategies in Humans- food resources= collection of food
such as fruit and leaves; extracted food such as termites, honey and tubers;
hunted food such as vertebrate prey.
Methods of food acquisition: Figure 12-3
Human Foraging- hunting, tuber extraction, hard to acquire food which
acquires hard to learn skills (promotes a long juvenile period).
Division of Labor- men: hunting, women: extractive foraging
Food Sharing: Chimpanzees- mothers with infants, meat sharing (small prey
usually not shared, large prey shared with other members of group).
Human Food Sharing- food sharing and division of labor in humans:
juveniles are consumers, middle aged men and postmenopausal women
Extractive foraging and hunting require intelligence and learning= large
brain, long juvenile period, increased longevity, paternal investment and
reduced dimorphism (less competition).
Meat eating favours food sharing
Archeological Evidence for Food Procurement- tools being used for a
variety of tasks, including large game butchery; wear patterns on bone
tools were used to evacuate termite mounds.
Tool Modes: Mode 1- carcass butchering, digging sticks; South Africa used
bone tools for termite extractive foraging. Evidence for meat eating is the
concentrations of butchered bones and tools. Stone tool versus teeth
markings on bone (determine what they used to take the meat off of bone
to eat= hunting: tooth marks on top of cut marks and Scavenging: cut marks
on top of carnivore tooth marks). Scavenging- is just as difficult and dangerous as hunting is; most of the large
mammalian carnivores practice hunting and scavenging (humans may have
stolen kills from carnivores).
Oldowan toolmakers had home bases; modern foraging societies (also a
butchering site; safe and away from predators)
Chapter 12- From Hominin to Homo
Origins of Homo- approximately 2.3 mya, Africa, larger brains, smaller
teeth, Australopithecus limb proportions and rapid development.
Early Homo- Homo habilis: about 1.4-2.3 mya, East and South Africa
Homo ergaster- evolved from early Homo (after coolings in
temperature), about 0.6-1.8 mya
Homo eragster Morphology- skull, Ancestral: postorbital constriction, no
or less pronounced chin, receding forehead; Derived: less proganthic,
larger brain, smaller jaws and teeth; Unique: brow ridge, occipital torus,
long legs, narrow hips, barrel chest, modern human body proportions,
reduced sexual dimorphism, terrestrial biped and has less of a
diaphragm= limited speech.
Note the importance in the differences in genus between the Homo
ergasters and the Homo sapiens.
Between 1.6 and 1.4 mya, H. ergaster improved on Oldowan tools and
added the Mode 2 of tools (technological innovation)= the first
Mode 2 tools- biface (hand ax), specifically designed, unchanged for 1
Evidence that H. ergaster ate meat includes the abnormality of the
bones of the women; the ubiquity of hand axes, cut marks in animal
bones from stone tools, the dental morphology and intestinal parasites
(didn’t cook the meat they ate). Hunting or scavenging the meat?
Unknown Vitamin A poisoning- by digesting the liver of a prey (rich in Vit. A) and
cause abnormal bone growth
H. ergaster- could likely control fire
Between 1.8-1.2 mya H. ergaster started to leave Africa and migrated as
far as the Caucasus Mountains; they were the first taxa to leave Africa.
H. ergaster was related to H. heidelbergensis
Homo erectus- discovered in the late 1800s, first fossil evidence for an
ape-human transitional species
Found in Java, Indonesia, dating to between 1.8 and 1.6 mya
Cranial differences: thicker skull, more massive face, more pronounced
occipital torus and brow ridge and sagittal keel.
Mode 1: in most localities; mode 2: present in rare circumstances
(possibly bamboo tools)
Homo ergaster in Africa and western Eurasia was related to Homo
heidelbergensis= large brain, large brow ridge, , no chin and prognathic
Homo heidelbergensis Tool kit- large game hunting= spears, butchered
animal bones; diversity of food resources; mode 3 technology= prepared
Homo florensiensis (the “hobbits”)- found in Flores, Indonesia about 16-
74 kya, small bodied (3 ft tall), small brained and used sophisticated
Neanderthal World- fluctuating environment, cooling trend, Eurasia,
frigid grassland and many large mammals
Anatomy- large brain (larger than Homo sapiens), oblong skulls (occipital
bun, thin- walled bones), unique teeth (taurodont roots= more pulp in
tooth and heavily worn incisors= used for more than just eating), short,
stocky, more robust limbs with better developed muscle attachments,
wide torso, short arms and legs.
Mode 3 tools- Mousterian (flint stone tools), large game hunters
Intelligence- caves as home bases but no shelters, burial of dead,
personal ornaments (cultural evolution) Life of Neanderthal- short life span, difficult lives (arthritis, gum disease,
injuries and caring for the injured).
Homo heidelbergensis is related to Homo sapiens in Africa about
200,000 years ago (some overlap with living Neanderthals)
Replacement of one hominin species by another; rests on the ideas of
climate change and adaptive radiation
Hominins split into several new species as they migrated out of Africa
during the Pleistocene
1-4% DNA in Europeans and Asians is shared with Neanderthals= mtDNA
is unshared between Neanderthals and m