Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
52 Cards in this Set
- Front
- Back
|
fossil
|
hard evidence of the existence of a species in the past
|
|
|
after death, bones can be destroyed by several forces
|
physical
chemical biological (scavengers crunching up bones) |
|
|
fossilization is promoted or enhanced if the animal dies:
|
in a cave
or near water |
|
|
fossil record is non-random (i.e. biased):
|
1. where fossilization is likely to occur
2. which species are more likely to be fossilized 3. discovery of fossil bearing deposits |
|
|
geological time scale
|
precambrian eon 4.6 bya - 570 mya
phanerozoic eon 570 mya - present >>paleozoic era 570 mya - 225mya >>mesozoic era 225 mya - 65 mya >>cenozoic era 65 mya - present |
|
|
cenozoic era epochs
|
paleocene: 65-55 mya
eocene: 55-33 mya oligocene: 33-23 mya (definitive proof of anthropoid ancestors of later monkeys/apes) miocene: 23-5 mya (definitive definition of apes evolve) pliocene: 5-1.8 mya pleistocene: 1.8 mya - 10,000 ya holocene/recent: 10,000 to present |
|
|
relative dating methods
|
stratigraphy
biostratigraphy paleomagnetism fluorine analysis |
|
|
stratigraphy
|
dating of a specimen based on its position in the ground
based on law of superposition: upper sedimentary layers are younger in age than lower layers |
|
|
biostratigraphy
|
faunal correlation
dating based on associated species whose evolutionary history is well known |
|
|
paleomagnetism
|
dating based on shifts in the earth's polarity
|
|
|
fluorine analysis
|
dating of specimen based on relative amount of fluorine
if there is fluorine in the ground water, it can harden the bones. if 2 organisms die at different times, the bones that were younger will have more fluorine in them. this aging technique can only be done at one geographical location |
|
|
chronometric (absolute) dating methods
|
elements have isotopes
isotopes release radioactive energy to achieve a more stable state. The rate of radioactive discharged is the half-life. half-life is the amount of time it takes for one-half of radioactivity to be released potassium argon dating. half-life is 1.25 billion years carbon 14. half life is 5,730 years |
|
|
fraudulent piltdown specimen
|
charles dawson discovered
it had different fluorine content compared to contemporaneous specimens mandible had different fluorine content than cranium bones were painted mandible belonged to orangutan, teeth filed down. cranium was human. |
|
|
suspects in piltdown hoax
|
charles dawson
arthur conan doyle martin hinton |
|
|
plate tectonic timeline
|
pangea: 224 mya
laurasia, gondwonaland: 135 mya continents today: 65 mya o North America and Europe were connected to one another during Paleocene and Eocene. Helps to explain geographical distribution of early primates. o During the Cenozoic Era, Africa was an island continent prior to 16 million years ago. At about 16 million years ago, Africa contacted Southwest Asia. Helps to explain geographical distribution of apes during the Miocene. |
|
|
how did lemurs colonize madagascar?
|
Best theory is that lemurs colonized Madagascar by crossing the Mozambique Channel on floating of masses vegetation.
|
|
|
how did monkeys colonize south america?
|
South America was an island continent long before the emergence of primates, and the Isthmus of Panama connected North and South America only about 2 million years ago.
Best theory is that the ancestor of New World monkeys colonized South America by crossing either the Caribbean Sea or Atlantic Ocean on floating masses of vegetation. |
|
|
Paleocene (65-55 mya)
|
putative fossil primates found principally in north america and europe
paleocene species were not primates -longer snout -eyes not at front of skull -no orbital bar -smaller brain -specialized dentition -claws, not nails -non prehensile hands/tail/feet |
|
|
anatomies that suggest paleocene species may be primates
|
anatomy of molar teeth
middle ear |
|
|
eocene (55-33 mya)
|
-first primates
-eyes face forward -post orbital bar -short snout -prehensile hands and feet -nails -large cranial capacity (compared to paleocene species) |
|
|
where fossils of eocene primates are found
|
found in north america and europe. also found in north africa and asia near the end.
north america and europe geographically connected in eocene by greenland. |
|
|
environmental context in which eocene primates are found
|
tropical and subtropical forests
|
|
|
two lineages of eocene primates
|
Adapids may be ancestral to lemurs and lorises
Omomyids may be ancestral to tarsiers and anthropoids |
|
|
inferences about eocene primates
|
-Some species were diurnal, whereas others were nocturnal
-Locomotion: quadrupedality and leaping -Diet: insectivory; Frugivory-folivory -Observation: absence of tooth comb |
|
|
where fossils are found in Oligocene and dates of fossils
|
Site – Fayum, Egypt
Dates – 33 to 35 million years ago |
|
|
environment of fayum site during ogliocene
|
tropical rainforest
|
|
|
taxonomy of oligocene anthropoids
|
Propliopithecines
-E.g., Aegyptopithecus -Dental formula: 2, 1, 2, 3/2, 1, 2, 3 -Same dental formula as modern catarrhines (i.e., Old World monkeys, apes and humans) Parapithecines -E.g., Apidium -Dental formula: 2, 1, 3, 3/2, 1, 3, 3 -Three premolar teeth in each quadrant of mouth; same dental formula as some modern platyrrhines (i.e., New World monkeys) |
|
|
phylogeny of oligocene anthropoids based on dental formulas
|
Propliopithecines may be ancestor of catarrhines
-Evolutionary divergence between Old World monkeys and hominoids had not yet occurred Parapithecines may be ancestor of New World monkeys |
|
|
Inferences about Oligocene anthropoids: locomotion
|
Aegyptopithecus – quadrupedal, slow climber
Apidium – quadrupedal runner and leaper |
|
|
Inferences about Oligocene anthropoids: body size and diet
|
Body size: 2 to 4 pounds for Apidium; 12 to 18 pounds for Aegyptopithecus
Diet: Frugivory |
|
|
Inferences about Oligocene anthropoids: time of activity
|
diurnal
|
|
|
Inferences about Oligocene anthropoids: social organization
|
Social organization for Aegyptopithecus may have been polygyny
Sexual dimorphism in canine tooth size implies polygyny |
|
|
sivapithecus
|
ancestor of orangutans. fossil specimen: GSP 15,000 (geological survey of pakistan)
chimps have broader septum than orangutans |
|
|
miocene importance
|
earliest hominoids. based on y-5 cusp pattern of molar teeth.
|
|
|
where miocene fossils are found
|
africa in early & late middle miocene.
asia- middle and late micene |
|
|
geological event that explains distribution of hominoids
|
-In the early Miocene, the Tethys Sea separated Africa from Europe and Asia.
-Approximately 16 million years ago, the Arabian plate partially separated from continental Africa and contacted southwest Asia. -This established a migratory corridor. -Subsequent to 16 million years ago, apes are found in Africa, Europe, and Asia. |
|
|
grouping of hominoids based on geography
|
african hominoids (23 mya)
-ex: proconcil & kenyapithecus european hominoids (16-11 mya) -ex: dryopithecus-found in france, spain, italy, and greece asian hominoids (15-7 mya) -ex: sivapithecus - found in turkey, pakistan, india, and china |
|
|
alternative grouping of hominoids based on dentition
|
proconsulines
-proconsul & dryopithecus -compared to sivapitchecenes, smaller molars w/ thinner enamel and a thin, gracile mandible sivapithecenes -sivapithecus & kenyapithecus -compared with proconsolines, have larger molars w/ thicker enamel and a thick, heavily buttressed mandible |
|
|
implication of dental differences
|
-proconsulines and sivapithicenes had different diets.
-proconsulines frugivorous -sivapithecenes- fruits, nuts, other hard objects -dental differences associated with climactic changes during miocene -during early miocene, broad tracts of forest. by middle and late miocene, the environment was more mosaic (forest, woodland, savana) |
|
|
phylogenies
|
-sivapithecus may be ancestral to pongo (facial similarity b/w pongo and gsp 15,000)
-no direct ancestor has been identified for pan and gorilla |
|
|
inferences
|
-proconsule has a monkey-like post cranium
-dryopithecus has anatomies suggsting arm-swinging locomotion -sivapithecus has some monkey-like anatomies. implies independent evolition of some anatomies b/w pongo and pan/gorilla |
|
|
gigantopithecus
|
-dates: 8-6 mya and as recently as 500,000 ya
-found in asia (pakistan, india, china, vietnam) -anatomy: small incisors ,small canines, and huge molars with thick enamel and heavily buttressed mandible -inferences: diet of tough consistency, body size 400-700 lbs, terrestrially adapted |
|
|
early hominid evolution
|
humans are unique in locomotion among living mammals
|
|
|
which species is earliest hominid?
two traits to ID hominid: |
bipedality
reduced canine size |
|
|
period of hominid fossil sites
|
late miocene and early pliocene are in africa
|
|
|
east and north central africa
|
open air sites
dated by potasium argon, paleomagnetism, and biostratigraphy famous sites: -hadar, etheopia -lake turkana, kenya -olduvai gorge, tanzania |
|
|
republic of south africa
|
limestone caves
dated by stratigraphy famous site: taung |
|
|
famous fossils
|
AL288 (lucy)
fossilized footprints - laetolia, tanzania taung child KNM-ER 1470 Bartlett homo |
|
|
AL 288 (lucy)
|
-member of species Australopithecus afarensis
-dated to 3.2 mya -found in Ethiopia -40% of skeleton preserved (3.5 ft, 60 lbs) member of species which was highly sexual dimorphic in body size. |
|
|
fossilized footprints
|
-3.6 mya
-early evidence of bipedality -australopithecus afarensis |
|
|
Taung child
|
first australopithecene found (1924 by Raymond Darte)
-australopithecus africanus |
|
|
oldowan
|
earliest stone tools
2.6 mya in Ethiopia also called pebble choppers. australopithecus garhi may have been earliest stone user |
