osteology: the descriptive and comparative study of bones and teeth.

its can provide us with a history of environmental adaptation, growth, and development, health and disease, diet, and activity, cultural practices, migration, mobility and marriage patterns.

isotopes can establish time frames

- our bodies incoroprate isotopes from the foods we eat. this makes it possible to identify the makeup of an individuals diet over the course of their lifetime.

it is important because it helps tell us who we are, and how we got here.  It can also be used for medical purposes, and for forensic purposes

phylogenetics are relating to evolutionary histories of ancestry and descent. its a cladistic approach.

darwins theory of evolution accounts for phylogenetic relationships among living and extinct organims and how new species may emerge from existing forms.

phenetics is an attempt to classify organisms based on their morphilogical features, regardless of their phylogeny or evolutionary relation.

phylogenetics represents evolutionary history more accuratly than phenetics

paleodemography looks at the changes in pre-modern populations in order to determine something about the influences on the lifespan and health of earlier peoples.

used to identify human dietary elements and residential history of an individual.

It looks at stable isotopes of certain elements in bones and other tissues of the body.

uses carbon and nitrogen atoms in bones and teeth.

an increase in the volume or mass of a tissue.

an example would be an individual who fished and travelled by canoe everyday, hypertrophy would be observed in the bicep region by studing the bones, after death.

the human skeleton is an open book, a tool in the reconstruction of

demography

work patterns

diet

genetic relationships and migration

disease history and other lesions

ethnomedicine

status and role definition

cultural variation and attitude toward the dead

forensic and criminal investigations,

human evolution

a surgical intervention where a hole is pierced into the skull

often times used to relieve pressure

it is rings on the teeth.

these rings can be used to tell if an individual has gone through periods of starvation, or not having enough food.

express theories about the natural world.

the goal is to reflect the natural order, and in doing so, reveal and respect the causes of biodiversity.

similar morphologies in unrelated lineages.

Like a whale and a shark

this is why phenetics is not a useful way of grouping organisms. under phenetics a whale and shark would be grouped together in the same family, when in fact they are not closely related at all.

similar for some reason other than a common ancestor.

this is observed in convergent evolution

homologous traits (synamorphies) are the useful traits in categorizing species in taxonomy.

a method of classifying organinisms into a group called a "clade"

it focuses on shared derived characteristics inherited from past ancestors

a diagram in cladistics that show evolutionary relationships among species. it represents the evolutionary tree of life.

morphological features are largely the basis of the diagram

the use of molecular data to reconstruct the evolutionary history of early primates and determine the time of divergence of different species.

this has resulted in the reconstruction of primate phylogeny

comparsions are made using amino acid sequences

opposable thumb and mobile grasping digits

nails, not claws in most primates

tactile pads on fingertips and toes

decreased olfaction and increased vision

expansion of the neocortex

exams fossils to determine organisms evolutionary history and interactions and their environments.

fossils are the types of evidence

reconstruct the natural history of our ancestors

reconstruct phylogenetic relationships

the guiding principles of this disciplince, is that life is old, and all life forms are delicate representations of their environment.

alternate term for anagenesis

a line of direct ancestor-descendant relationship

a slow, gradual change

a type of evolution characterized by the gradual change, without divergence, of an entire group of organisms

species that live apart and do not occupy the same geographic location.

speciation by geographic seperation

one group becomes seperated, and the seperated group diverges from one another. when the reunite and are unable to have offspring, allopatric specidation is complete.

start with species, genetic barrier isolates a segment of the population without any separation of the ancestral range. (the thieving birds whose offspring grow to sing a different song)

two populations seperate, but one is much smaller than the other.

genetic drift and bottleneck play signifigant roles in this type of speciation

it is just like allopatric speciation, except that one of the two seperate groups is much smaller than the other

-    Tiny changes accumulate over a long period of time gradually via microevolution.

Slow progression of one species to another

anagenesis is evolution within a lineage.

cladogenesis is evolution that results in the splitting of a lineage

Short periods of rapid change or long periods of little to no change.

evolutionary relationships among species.

Higarcheal family tree with descendents branching from ancestors

    - importance of phylogeny is that it is used for the classification and identifications of species (taxonomy)

    -  helps explain why certain species evolved certain adaptations and not others, and tells us when        and where in the family tree did a certain adaption evolve.

extinction is normal

we are currently experiencing much higher rates of extinction that is to be expected from observing the fossil record.

fossils: comparative morphology & dating: Mineralized remains of tissues, tracks or trails. Whole organisms in anoxic and inorganic environments

·         Taphonomic screening (taphonomy)

­   Cause and manner of death, decay, decompostions, transportation, burial, chemical alterations.

·         Comparative anatomy: cladograms and phylogenies, phylogenetics

2. biochemical data

3. ontongeny

4. analogous behavior

cause and manner of death

decay

decompostition

transportation

burial

chemical alterations

a absolute method of dating based on the radioactive decay of isotopes

cannot be used to date primate sites exceding 50k yrs. it is the method of using measuring carbon

relate a fossils age to something else (other fossils, paleolithic cultures, geological events)

doesn't determine an absolute age

paleolithic is an age of using and creating tools

artificats tell us about the culture during this time.

immune response

amino acid sequences

DNA hybridization

genome mapping

a method to determine phylogenetic relationships by splitting strands of DNA from two seperate species, then mixing together one strand from each species.

the more closely species are related the more closely the DNA will match, creating a stronger bond between the two strands

eocene primates

where?

characteristics?

the first primates (53-37MYA) Euprimates

where: north america, asia, europe. warm and wet tropical environments.

First unequivocal primates (~50 MYA): characteristics
● forward facing eyes
● post-orbital bar
● reduced snout
● large brain
● vertical incisors
● nails not claws
● tactile pads on digits
● opposable thumb and big toes
● long tail
● supple back

in general…
● increased reliance on vision
● increased reliance on touch/manipulation
● diet: insects & fruit
● locomotion: acrobatic leapers

Each party in a coevolutionary relationship exerts selective pressures on the other, thereby affecting each other's evolution.predator and prey

Coevolution of predator and prey species is illustrated by the Rough-skinned newt (Taricha granulosa) and the common garter snake (Thamnophis sirtalis). The newts produce a potent neurotoxin that concentrates in their skin. Garter snakes have evolved resistance to this toxin through a series of genetic mutations, and prey upon the newts. The relationship between these animals has resulted in an evolutionary arms race that has driven toxin levels in the newt to extreme levels. This is an example of coevolution because both organisms changed to better increase their chance of survival.

global warming even t took place which led to a signifigant increase in tempatures, and tropical forests covered much of north america. these conditions faciliated the appearnce of primates, possesing characteristics like forward facing eyes,, a postorbital bar, and a reduced snout compared to plesiadapiforms.

oligocene

when, and where?

characteristics and trends

37-22MYA

OWM and NWM (anthropoids)

Diagnostic traits of anthropoids:
(relative to Prosimians… lemurs, lorises & tarsiers)
1) large brain
2) reduced snout
3) thick jaw
4) high face
5) bony wall enclosing socket
6) very forward facing eyes

orbital closure is almost complete
● lacrimal bone in orbit
● fused mandibular symphysis
● larger brains
● …in Aegyptopithecus zeuxis
Y-5 molar pattern
…Is characteristic of the
superfamily Hominoidea

further increased reliance on vision
● increased sexual dimorphism
● increased brain size
● increased frugivory
● increased social living

OWM evolved lost the fifth cusp on the lower molar developming bilophodontry

great apes and early hominins developed the y-5 cusp pattern by the 5th cusp on the lower molars moving outwards.

[image]

two transverse ridges in molar teeth

this is seen in OWM

when was the miocene?

what is this age called

22.5MYA

this is called the "golden age of apes"

increased body size
● increased cranial capacity
● brachiation
-shorter legs
-no tail
-thorax wide & shallow
-scapulae more posterior
-very mobile shoulders

hominidae is known as the great apes. its had includeded four extant. (chimp,orang,gorilla, human). now the taxonomy has been updated. chimps and humans are still hominidae, but gorilla and orangutan have been given a seperate branch in hominoidae

hominoidae is the super family to which hominidae belongs. this group can include prosimians, lesser primates, and great apes

why do we consider the following species to be hominins?

until 1998: Australopithecus afarensis (4 MYA)
~ now:
Australopithecus anamensis (4.2 MYA)
Ardipithecus ramidus (4.4 (5.8?) MYA)
Ardipithecus kadabba (5.2-5.8 MYA)

1. location of the foramen magnum (inferior, not posterior)
2. ―S‖ curve of the spine
3. Os-coxa – shorter & broader, rotated anteriorly
4. femoral neck is more robust & femur is angled medially
5. tibia with two concave depressions in superior surface
6. foot- robust talus,
arched,
hallux in line

these traits show that they were bipedal

carrying, weapons and tools, carrying food water and infants, travelling from trees, feeding from bushes, feeding on grass and seeds,

there is likely no single reason for the development of bipedalism

likely monkeys rafted from africa to south america

it has found not to be convergent evolution as it seems that playtrrhines have evolved from african monkeys

he discovered austrapolithicus africanus in 1924

this was the "taung child"

parabolic has a jaw, and dental ridge, that is U shaped

non parabolic has a V shaped jaw

people thought that mankind had originated in Asia, but the Taung child was found in Arica.

at the time it was thought that a big brain had to evolve before bipedalism. the taung child had a small brain, and the evidence showed that it was bipedal.

the jaw and cranium morphology was nothing like the "Piltdown man" which eventually turned out to be a hoax
(1912, 1915, cc = 1400 ml, ape teeth)

many thought that it was just a juvenile gorilla. since taung child was juvenile, it was difficult to dispute this claim.

he was a surgeon, and an expert on the reptile/mammalian split.

he discovered fragments of 6 individuals that were found to be austrapolithicus africanus.

In 1937, he discovered paranthupus robustus

 (5-7 MYA)

Biped?
maybe
Implications?
…earliest hominins more widely distributed than we thought
…chimp / human split earlier than indicated by most DNA studies

Cranial Capacity: 400 ml
Teeth: more human-like, but still big canine,
asymmetrical PM3, not quite parabolic
Post-Crania: more derived than anamensis,
biped with arboreal adaptations:
- curved hand & foot bones
- highly mobile wrist & ankle
- shoulder joint oriented more toward
head than in strict bipeds
- short hindlimbs

Ancestral to?: A. africanus, H. habilis, robust
forms
Significance: pushed earliest date back 1MY,
used various habitats

pliocene hominins

robust forms

homo habilis

when and where

What do we know now about Homo habilis?
(2.0—1.6 MYA… maybe 2.4—1.4 MYA)
East & South Africa
N > 11
Cranial Capacity: 640 ml (750?- KNM-ER1470)
(australopithecines ~ 500 ml)
Teeth: similar to A. africanus but with “Homo-like”
relatively large I’s, smaller C, PM & M’s.
Post-crania: obligate biped (shorter toes, hallux more in
line), fully developed arch in foot (OH 8), some
arboreal adaptations in foot (agrees with habitat…
marginal woodlands), 32 kg
Ancestral to?: H. erectus

Significance:
a. “wastebasket” species?
b. contemporaneous with
paranthropines & H. erectus
c. first tool maker (?)
(Oldowan)

what is "leims's paradox"

This discrepancy between phenotypic and ecological specialization is what has come to be known as

Palaeontological analyses of function are commonly underpinned by the assumption that an organism’s ecology and anatomy are closely correlated. However, analysis of extant animals reveals that morphologically specialised species often behave as generalists, especially with regard to feeding. Specialist trophic modes are adopted only during times of critical resource scarcity

homo habilis

some have felt habilis represents a single species with wide ranges of morphology, and others believe it represent multiple species. Notable paleontologist Ian Tattersall once called it a “wastebasket taxon” due to the “motley” bone assortment attributed to it. The most complete specimens are only two very fragmented skeletons.

there is tremendous variability within habilius fossils

faculative is optional bipedalism

obligate is the animal having no reasonable alternative

a method of relative dating that involves comparing reversals in the earths magnetic field

examine shifts in the earths magnetic field and compare it to other sites that have been securely dated using methods of absolute dating, which can indicate an approximate age

linnean taxonomy is based on similarity between organisms

modern taxonomy has welcomed evolution. classifications reflect the phylegeny of organisms by grouping them closer to their ancestors.

the study of different layers of strata that have been deposited over time.

a method of relative dating that involves dating a fossil based on associated faunal remains that have been securely dated using other methods.

for example,a primate fossil found with the remains of an extinct species of pig known to have lived between 35-40MYA would, by association, be considered to fall within the same time range.

a fissure found in the anterior portion of the occipital lobe that demarcates the primary visual cortex; readily visible in nonhuman primate brains. it is not often seen in humans.

this suggests that brain reorginization occurred before volume increases in primates.

the brain takes 2% of our body mass, but requires 15% of cardiac output, and 20% oxygen consumption, 25% of glucose utilization.

while resting the brain relies on simple sugar glucose as its energy source.

The brain is not an economical organ to keep running.

growing a larger brain accompanied changes in how brainier hominins captured energy. The hominins likely would have had to change both diet, and activity levels.

from the dietary changes, shifted towards smaller teeth, and jaws

the bodies essential organs bear "fixed costs", that is, they have specific energy demands that must be met in order to maintain function.

a shift from intestinal tract size to brain size was achieved by adopting a diet with more meat and fewer fibrous, plant-based resources, which require a large intestinal tract for processing.

this would have increased the importance of hunting game, which can only effectively be done by cooperative ways in an increased group size.

how does valentine suggest we measure the completeness of the fossil record.

what does he conclude about the completness of the fossil record.

he suggests that you compare the total number of fossils with an estimate of the total number that ever lived.

over 1 percent of all animal species that have existed, are in the fossil record.

it seems like a small amount, but many statistics are used with much less.

he concludes that many inferences can be made by the current fossil record.

a recent proposal based on paleoenvironmental data from fossil localities that the hominin clade diverged from panins while still occupying a woodland/forest habitat

suggests that the operating factor in hominin evolution was environmental disparity, rather than stability, which promoted adaptive flexibility in hominin traits, including locomotion, dental adaptations, and technology.

fluctuating conditions created a diversity of adaptive conditions to which species needed to respond. this was achieved by favouring morphologies and behaviours that would work in complex, changeable multi-habitat situations.

planning of movement, visuospatial problem solving, procedural learning, working memory, attention switching, and languague.

it is larger in apes than in monkeys.

may have developed and facilitated tool making

having large teeth.

species have huge, broad cheek teeth with thick enamel while their incisor teeth stay small. The emphasis for megadont species is on the rear teeth, which are designed to support the stresses of heavy chewing. Combined with the morphology of the other parts of the skull -- large zygomatic arches to allow the passage of large chewing muscles and a large sagittal crest to provide a large area to anchor these muscles to the skull -- megadont early humans showed adaptations to chewing tough, fibrous foods.

assigns a specific age and estimated error to a fossil or site

methods are based on the decay of radioactive elements in organic or inorganic material

they measure stable, and unstable forms

radiometric dating: carbon-14 decay rate. its only useful for dating sites within the last 50k.

accelerator mass spectrometrey dating: it is used for dating for small objects like hair, or seeds etc.

radical reconstruction of the pelvis and a reshaping of the birth canal through which the fetus passes.

the infant as to shift, side to side, and front to back. These is especially difficult with larger brains and rigid shoulder anatomy

it is possible that knuckle walking proceded bipedalism. this would imply that it is a primitive trait for hominins.

it is also argued that Orthograde clamber (a form of arboreal hand assisted bipedcal locomotion applied specifically to orangs, involving extension at the knee, hip and shoulder) is a more probable theory.

it argues that there was a transition from tree to ground.

is the sharpening of teeth by the canine by repeated contact with another tooth.

this is important for males living in a competitive multi-male primate society in which aggression plays a signifigant role.

canine reduction suggests changes in hominin social organization

suggests important changes in early hominin social organization.

it is suggested that a behaviour hallmark of hominin evolution is associated with reduction in canine size.

we would see decreased male-male competition and a increase in social relations.

speciation has two tempos, slow and gradual (anagenesis) or rapid followed by stasis(puntuated equilibrium); punctuacted anagensis combines these into a pattern of rapid change within a continually evolving lineage; the possibility of punctuated anagensis is not universally held among evolutionary biologists.

slowly evolving lineage is suddenly marked by a rapid speciation event.

the earliest stone tool. characterized by pebble and chopping tools made and used by early hominins

tools were made by percussion (striking one stone with another)

-          Georgraphic separation of species ( so no gene flow) two populations are separated and because of their new niches or selection pressures they eventually evolve into two or more separate species. There is no interbreeding. (example bonobo and chimpanzees being separated by a large river and unable to attempt to breed)

Allopatric speciation (from the ancient Greek allos, "other" + Greek patrida, "fatherland") or geographic speciation is speciation that occurs when biological populations of the same species become isolated due to geographical changes such as mountain building or social changes such as emigration. The isolated populations then undergo genotypic and/or phenotypic divergence as: (a) they become subjected to different selective pressures, (b) they independently undergo genetic drift, and (c) different mutations arise in the populations' gene pools.^[1]

The separate populations over time may evolve distinctly different characteristics. If the geographical barriers are later removed, members of the two populations may be unable to successfully mate with each other, at which point, the genetically isolated groups have emerged as different species

An example of this would be the 15 species of Darwins finches on the Galapagos islands that most likely originated from a single species arriving from Central or South America. When the original species immigrated to the Galapagos they brought with them their own genetic diversity, or sampling variation. This variation combined with new environments in the Galapagos created a genetically distinct population from the parent population.         

a. the functions are the planning of movement, visospatial problem solving, procedural ldearning, working memory, attention switching, and language.

b. the neocerebellum was larger than expected in apes than in monkeys. when regrised against the vermis, it is 2.7 times larger than the monkeys

c. its tells us that they were tool makers and users, and complex feeding strategies.

the paper was generally rejected by the scientific comm unity

b. the origins of man at the time, were thought to be in Asia or Europe. The fact that aricanus was found in Africa, was an outrageous claim.

it was believed that humans surely would have evolved from an ancestor with a larger brain.

Africanus was inconsistent with the Piltdown man, which was later proven to be a hoax.

it was argued that africanus was nothing but a juvenile Gorilla. because dart's africanus was a juvenile, it was hard to build up an argument against this accusation.

a. What is the tradeoff described by the “expensive tissue hypothesis”?

b. How do Aiello and Wheeler suggest our ancestors adapted to the related increased energy requirements?

c. What do the data tell us about the “expensive tissue hypothesis”

a. the tradeoff is a shift of energy resources from intestinal tract size to brain size.

b. they adapted by adopting a diet that consisted of more meat and fewer fibrous, plant-based resources, which require a large intestinal tract for processing.

c. the data has confirmed the general premise of energy tradeoffs among "expensive" tissues. an example would be a correlation between pectoral size and brain size in birds.

a. What are some of the explanations for the reduction in canine size in the evolution of hominins?

b. Which do you find more persuasive and why

a. "dual selection" hypothesis describes how less intrasexual competition (e.g using teeth to fight males for females), and a shift to using canines as modified incisors to process food selectively favoured smaller canines.

canine reduction suggest important changes in early hominin social organization. male-male competition has decreased and relations in cooperation and coalition have increased. this would remove selection for larger canines.

b. the dual hypothesis is more persuasive. It makes that, less intrasexual competition would move alot of the selection pressures for larger canines. also, using the incisors more would place less emphasis on the need for larger canines.

It has long been argued that the paranthropines (P. aethiopicus, P. boisei, P. robustus) went extinct because they were dietary specialist who were unable to change their dietary practices when their environment changed.

Several lines of evidence have lead paleoanthropologists to revise these conclusions.

Describe this evidence and the current state of knowledge concerning the diet of the paranthropines

dental microwear have recently been studied of several boisei and the pattern of wear is not consistent with a constant diet of tough, fibrous food.

the morphology of the paranthropines seems to suggest that their diet consisted of tough, fibrous foods. We now know that a species can evolve a specialized phenotype for fallback foods when prefered resources are not available. this is known as liams paradox. This also doesn't stop them from eating more easily processed food. This suggests they they were more of dietary generalists.

the results show that they were not any more specialized than any of the earliest member of the genus homo. They likely at all sorts of food.

Are the hominin fossils found on the Island of Flores evidence of a new species or are they evidence of a diseased
modern human?

Describe three (and only 3) lines of evidence to support your answer

the fossils are evidence of a new species

the trapezoid was triangular in shape, unlike a human, and much like a nonhuman primate.

brain of the hobbit and individuals who were microsyphalic, were compared and the brain appeared to be signifigantly different than those who are microsyphalic.

when examinations on the skeleton were completed, they had found no reason to support that the hobbit was sick, or had any type of disease.

a. What is the savannah hypothesis?

b. In evaluating this hypothesis, what data are considered?

c. Do these data support the savannah hypothesis (why or why not)?

a. the savannah hypothesis is the now discredited idea that the loss of forest habitat and  development of open savannah grassland created conditions leading to the evolution of hominins

b. when the hypothesis was popular, there was little evidence disputing this claim. the fossils that had been found, were discovered in savannah like environments. We now have a much larger fossil database, and several hominin fossils have been found in what would have been forested habitats. many fossils suggest that hominins kept close to water sources, to which there isn't many, in the savannahs

the data does not support the savannah hypothesis because most fossils have been found in forested areas, suggesting that hominins were better suited, or adapted, for forested areas