Midterm 3 study guide - bio anth

Taung Child

- Species of Australopithecus africanus

- Small brain (440cc), bipedal

- First individual australopith described

Raymond Dart

- discoverer of Taung child, first australopith (africanus)

Endocast

a cast of the inside of a skull; used to help determine the size and shape of the brain

Orthognathic

a flat face - associated with a decrease in molar tooth size

Prognathic

Protruding jaw

sagittal crest

Bony projection on top of the cranium for attachment of chewing muscles

Diastema

space near teeth to make room for large canines

Foramen Magnum

A large opening at the base of the skull through which the brain connects to the spinal cord

Tuang Child's foramen mangum

more centered below the skull, suggesting bipedalism

Australopithecus Africanus

- first discovered hominin species

- discovered in south africa

- long arms and curved phalanges(fingers); adapted for climbing trees

- high sexual dimorphism

- shorter relative legs than humans

- low canine dimorphism

- less hard foods; middle of the road

Eoanthropus Dawsoni - Piltdown Man

Fraudulent hominin find - sowed doubt in Taung Child/Dart

Sterkfontein

- limestone caves located in South Africa

- STS 5; Skull of Mrs. Ples (A. Africanus)

- STS 14; Pelvis, vertebrae, femur (A. Africanus)

STS 5

Skull of Mrs. Ples (A. Africanus) (Sterkfontein)

STS 14

Pelvis, vertebrae, femur (A. Africanus) (Sterkfontein)

Showed bipedalism;

-pelvis; lesser gluteals

-femur angled outward; balanced stride

-vertebrae; Lumbar Lordosis (spine curve)

Lesser Gluteal

Muscles that abduct (side to side)

CRITICAL FOR BIPEDAL BALANCE

Bicondylar Angle

Abducting hip position/femur angled outwards, keeps us walking in narrow line

takes stress off of lesser gluteals; efficient bipedalism

Lumbar Lordosis

Lumbar (lower back) is s-shaped; moves center of gravity back over hip joint

Kromdraai

Broom found fossils at this site in South Africa but named a new genus for them, Paranthropus robustus.

Swartkrans

Discovery site of SK 48; Paranthropus robustus skull

- fire may have been used here

Paranthropus robustus

-sturdier and muscular hominin

-Sagittal crest supported large temporalis muscles for chewing

-large teeth

-likely ate hard foods

-large mandibles (robust jaw)

-wide cheek bones

-bowl like face

-was proof of nonlinear hominin evolution

-younger than A. Africanus

Temporal Foramen

hole in skull that temporalis muscles pass through to reach mandible (lower jaw)

Australopith

broad term for all Paranthropus (robust) and Australopithecus (gracile) species

Shared traits relative to chimpanzees:

-brainer

-less prognathic

-smaller canines

-medium hardness foods

Megadontia Quotient

measure of premolar/molar tooth area relative to body size

Hominin teeth

Generally huge compared to body size (relative to humans) and very thick enamel

Homoplasy

A similar (analogous) structure or molecular sequence that has evolved independently in two species;

ex. chickens and flies both have wings

Homologies

similarities resulting from common ancestry;

whale flippers and human hand similarity

-helpful in establishing evolutionary relationships

Derived Traits

newly evolved features, such as feathers, that do not appear in the fossils of common ancestors

ancestral traits

more primitive characteristic that appeared in common ancestors

Phylogeny

Evolutionary history of a species

Outgroups

closely related to X, but not X's group

Cladogram

Diagram that shows the evolutionary relationships among a group of organisms

Cladistics

A phylogenetic classification system that uses shared derived characters and ancestry as the sole criterion for grouping taxa

clades

A group of species that includes an ancestral species and all its descendants; features shared derived traits

Monophyletic

shared characteristics / all descended taxa

-can't evolve out of being a mammal for example

Paraphyletic

"incorrect" basically; does not have all descended taxa; typical of outdated and incorrect taxa

Polyphyletic

groups based on traits that are convergent

convergent traits

Similar traits, devloped individually (i.e. bipedalism in humans v. chickens)

Biological Species Concept

Species is a group of populations whose members have the potential to produce fertile offspring

Hybrids

offspring that result from an interspecific mating - many are sterile, but ligers can mate with lions for example

Ring species

a connected series of neighboring populations that can interbreed with relatively closely related populations, but for which there exist at least two "end" populations in the series that are too distantly related to interbreed.

Morphospecies

species defined by anatomical features

intraspecific variation

Differences between organisms of the same species

interspecific variation

variation among members of different species

Law of Superposition

The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it

Biostratigraphy

relative dating technique using comparison of fossils from different stratigraphic sequences to estimate which layers are older and which are younger

Absolute/Chronometric Dating

a method of dating fossils in which the actual age of a deposit or specimen is measured

Dendrochronology

Tree ring dating

40k/40Ar

Potassium/Argon dating;

1.3 billion year half life

Uranium/Lead Dating (U/Pb)

Use uranium decay compared to lead half life to date in ranges

Speleothem

sheet of flat calcium carbonate rock

often used for U/Pb dating (which dates in ranges)

Lucy

Famous Australopithecus afarensis fossil discovered in 1974

Sexual Dimorphism in A. Africanus and P. Robustus

more than chimpanzees

Amelogenins

proteins responsible for growing/shaping enamel; two forms- y and x chromosomes; amel x/amel y

Amelogenins and fossils

because they are carried on x and y, amelogenin analysis can reveal gender of teeth/fossil

Drawbacks of big canines

low mouth mobility; difficulty grinding with molars

Potential causes of bipedalism

carrying

postural feeding

energy efficiency

thermoregulation

Carrying hypothesis for bipedalism

championed by Lovejoy; Carrying of food or young, male brings home food and needs to carry shit--hypothesis lacks direct evidence

Postural feeding hypothesis for bipedalism

need to stand and pick fruit from bushes and trees

Energy efficiency hypothesis for bipedalism

championed by Rodman and McHenry; bipedalism is more energy efficient than quadrupedalism

-fruit distribution lessens, so had to move efficiently to patchy forests to find food

Issues with theories of bipedalism

General lack of evidence, so its hard to say which cause prompted the evolution of bipedalism

thermoregulation hypothesis for bipedalism

bipeds get less sun generally, so bipedalism would be efficient; theorized that up to 40% less water needed

East African Rift / dating

as Africa splits at the rift, layers are exposed for argon/argon dating

Hadar site

Site in Ethiopia (East Africa), Lucy's home

Australopithecus Afarensis discovery site

Patellar groove

where patella articulates with the femur (at the knee);

keeps knee from slipping out due to bicondylar angle

AL 288-1

Lucy; A. Afarensis - found at Hadar in Ethiopia - 3.2myo

Dikika site

Neighboring Hadar; more A. Afarensis - 3yo skull found

Laetoli footprints

earliest direct evidence of hominin bipedalism; 3.6 million years old; footprints preserved in a layer hardened volcanic ash

Laetoli site

Tanzania, Conclusive Evidence of hominin bipedalism

Holotype

a single type specimen upon which the description and name of a new species is based

Burtele foot

- 3.4 Myo

- Middle Awash

- Divergent Big Toe

Kenyanthropus platyops

A proposed genus and species of biped contemporary with early australopithecines; may not be a separate genus

Australopithecus afarensis

- smaller than A. Africanus

- discovered in eastern Africa

- generally more primitive

- prognathic face

- large canines/canine dimorphism

- smaller teeth than P. Robustus

- thick enamel

- powerful wrists for trees

- cranially primitive

Australopithecus anamensis

- oldest species of australopithecine from East Africa

- likely ancestor to A. afarensis

- wide canine

- small brain

Amaris site

- 4myo

- discovery of Ardipithecus Ramidus

-

Ardipithecus Ramidus

- best dated species (4myo)

- discovered at Amaris

- chimp-esque brain

- big canines, small teeth, thin enamel

- likely upright at times, but not always

- pelvis more humanlike than chimplike

- probably bipedal on ground, quad in trees

Orrorin tugenensis

- 6myo

- big canines, small teeth, thick enaml

- curved fingers for trees

- strong arms

- indicators of bipedalism; obturator externus groove (groove on femural head, tendons run across back of femur)

Sahelanthropus tchadensis

- small canines

- flat face

- chimp size brain

- earliest pre-australopithecine species found in central Africa with possible evidence of bipedalism

- probably not an actual hominin; evidence is locked away...hmmm

Nonlinear Human Evolution

Humans did not evolve from a single line; there were multiple different bipedal hominins of different lineage, we are simply the survivors

Olduvai Gorge

- 25 mile rift in Tanzania (E. Africa)

- 1.8myo stone tools found

- home of Paranthropus Boisei / OH 5; Zinj

OH 5

Zinj; Famous Paranthropus boisei skull found at Olduvai Gorge in Tanzania in East Africa

- dated with K/Ar; 1.8myo

Paranthropus Boisei

- small canines

- wide cheeks

- sagittal crest

- flat face

- similar to P. Robustus

- 1.8myo

- ate SOFT foods, surprisingly; may have fallen back on hard foods during hard times, preferring soft foods overall

OH 7

- First homo; Homo habilis

- jaw, skull, foot

Homo habilis

- small teeth

- big brain (657cc)

- prognathic face

- very dexterous hands

Cerebral Rubicon

minimum cranial capacity required for a specimen to be classified as a certain paleospecies or genus; around 700-750ccs

Koobi Fora

- site for oldest H. erectus; possible use of fire here

- multiple species at large

Homo rudolfensis

- 774cc cranium

- orthognathic face

- discovered at Koobi Fora

Animals frequency at hominin sites

Animal fossils are common at early homo sites--helpful in determining diet and environment

Alcelaphinae

the SUBFAMILY of Family Bovidae that consists of the wildebeest and topi

Bovidae

have horns (cows, buffalo, sheep, goat, antelope, gazelle): bony core with keratin sheath on outside, never shed. all males have horns and often females

-presence in fossil record indicates grassland environment

Duiker

a small African antelope

Tragelaphini

spiral horned antelopes found near Australopithecus sites

Homo ecology

when Homo starts to show up, we see lots of grazing animals and less arboreal species; this suggests grasslands, which helps determine diet

Australopithecus ecology

more wooded areas than Paranthropus and Homo

C3 plants

the most common and the most efficient at photosynthesis in cool, wet climates

C4 Plants

plants that have adapted their photosynthetic process to more efficiently handle hot and dry conditions

Ardipithecus environment

potentially lived in forest pockets in grasslands

Palynology

the study of fossil pollen grains and spores to reconstruct past climates and human behavior

stone tool use

used to process plants and animals for consumption

frugivore teeth

Large, broad incisors. Low cusps for crushing soft fruits

folivore teeth

Long crests on molars, good for shearing cellulose

(mountain-like)