Primate Evolution, Human Origins, and Archaeological Science

Archaeology

Study of past material culture(artifacts) and its associate environmental residual information to explain the origin, nature and development of past human lifeways

Physical Anthropolgy

Study of comparative anatomy of apes and humans including the lower primates and fossil hominids

Cultural Anthropology

An integrated system of learned behavior patterns which are characteristic of members of a socity and hich are not the result of biological inheritance. It is unique to an, it is learned and trasmitted, it is sybolic and it is not instinctive

Evolution

Convergent Evolution

Alteration of gene frequencies or the alteration of the proportion in which different genes occur in a given species, as a result of natural selection. Evolution constitutes change that is continuous and ordered.

Extinction

Geographic Isolation

Biodiversity (Biological Diversity)

Adaptation

An evolutionary change resulting from natural selection which better suits a population to its environment thus improving its chances for survival; organisms that have the traits that enable them to efficiently exploit the environment as well as to weather the extremes the environment has to offer, are better adapted.

Pre-adaption

The potential to adapt, this may be passed to next generation through genetic material.

Natural Selection

A process which operates on accumulated variations and on chance. It relates to selection pressure whereby undesirable (maladaptive) physical traits are eventually eliminated from the gene pool. Through natural selection differential reproductive rates in the population occur so that better adapted individuals contribute more to the next generation than less well adapted individuals.

Selective pressure

Involved when the environment in which a species lives sets the conditions (e.g. climatic, vegetative, etc.) under which that species must live. As the environment changes, these conditions change as well, imposing new conditions under which a species must live. If individual species have traits that are well-adapted to the new environment, they will survive and reproduce. The less well-adapted species face increased competition, lower reproductive rates, and possible extinction.

Fitness

Adaptive radiation

Succession

Niche

Endemic Species

Pioneer Species

Semi-Endemic Species

Semi-Pioneer Species

Punctuated and dynamic equilibrium

A new trait quickly manifests itself within a population causing a significant shift in the course of evolutionary change

Gradualism

Slow and consistent change in the evolutionary course of a species (also called phyletic gradualism)

Phenotype

Trait

The observable characteristics of a plant or animal (as opposed to genotype) including internal and external characteristics.

One aspect of a phenotype

Genotype

Genetic makeup of a living thing (plant or animal) that contains all information in the organism's genes.

Genes

Gene pool

Are distinct units of the chromosomes in cell nuclei, which control the coding and inheritance of physical traits.

All genes of a population at a given time

Alleles

Mutations

Occurs at random in a population when chromosomal aberrations (in number or structure) create new genetic material in a population. The mutation can be a chromosome break, a duplication of genetic material, or translocation or reversal of genetic material on the chromosome. Mutations provide the variability for natural selection to take place, giving rise to new genetic material.

Macro-mutations

A macromutation is one which causes a key shift in the evolution of a species.

Derived traits

Mendel

In the mid-1800s, Gregor Mendel, by carefully controlled experiments with cross-fertilizing pea plants, was able to observe how traits are passed from parent to offspring. He was able to determine that heritable units are transmitted in pairs. While hybrids may be produced in the first generation, the traits that were present in the original parents, may emerge intact in the third generation. This is the principle of independent assortment, i.e. that heredity units remain intact through generations.

Acquired Characteristics

Another mistaken notion was that acquired characteristics were passed on to next generation.

Artifacts

Are the primary focus of archaeological study, but in themselves have little value without context.

Blending

This was a now defunct theory that held that genetic material was mixed or blended from generation to generation. Mendel's experiments and others showed this to be untrue. It did not account for passing advantageous or adaptive traits from parent to offspring. Rather, it held that these traits were diluted from one generation to the next. Mendel disproved this by showing that discrete individual traits were passed on through particulate inheritance.

Speciation

Genetic Drift

Random changes in gene frequency; occurs more rapidly in small or geographically isolated populations subject to low selection pressures

Founder Effect

Where a small population becomes isolated from its parent species. Existing in isolation with this new gene pool, which is not exactly typical of its parent species, differences in the gene pool may be accentuated over a period of generations.

Superposition

The older layers are ordinarily the deepest.

Stratigraphy

The relationship of layers of earth (and rock) to each other. This involves principle of superposition. For archaeology, the concept is adapted from geology originally. Based on this concept, archaeologists excavated sites in natural levels or arbitrary if none are apparent.

Radiometric Dating

An absolute dating method (e.g. Carbon-14) based on the radioactive decay of an unstable isotope into a more stable form as measured by a half-life.

Radiocarbon Dating (C-14)

Carbon-14 has a 5,730 year half life, i.e. the time it takes for half of a sample to decay to the more stable carbon 12. Carbon 14 is produced in the atmosphere by cosmic radiation. The radioactive carbon combines with oxygen into CO2 and is absorbed by plants and animals in the same ratio it is found in the atmosphere. When the plant or animal dies, the intake of carbon ceases and the radioactive decay process begins. Accelerator Mass Spectrometry dates on samples of less than .01 gram of charcoal. Allows more direct and accurate radiocarbon dating.

Potassium-Argon Dating

Potassium 40 (K40) has a 1.3 billion year half-life. K40 is an unstable isotope and is a natural constituent of volcanic materials (ash). Over time K40 decays to the more stable Argon 40 (Ar40). Because of the long half life, it is not possible to date materials younger than 500,000 years. The amount of Ar40 vs. the remaining K40 is measured to determine the absolute time span that has elapsed.

Absolute Dating

Relative Dating

Uniformitarianism

This is a concept which holds that forces responsible for change today are the same as those that created it in the past. This allows us to reconstruct events which occurred in nature during the past and also allow us to predict future trends, to some degree. examples: river activity (i.e. floodplains), glaciers, fossilization, wind and weather patterns

Catastrophism

Fossilization

When an organism dies, its structure may withstand decay completely for a time, but ultimately, portions of the organism (esp. skeletal material) are replaced with minerals, replicating the original structure but in stone. The same process may occur in situations where an organism leaves an impression (i.e. foot print) in the soil. The matrix in which the impression is made hardens with time and becomes fossilized. Even soft bodied organisms may leave fossilized impression that will preserve through time.

Index Fossil

Context

The association of artifacts among themselves within meaningful spatial patterns.

Paleocene

65-58 mya

Eocene

58-36 mya

Oligocene

36-23 mya

Miocene

23-5.2 mya

Pliocene

5.2-1.7 mya

Pangea

Laurasia

Tethys Sea

Anthropoids (Simians)

Hominoids (Superfamily)

Hominids (Family)

Genus

Sexual Dimorphism

Terrestrial Feeding Posture

Bipedalism

One of the characteristics of humans (and hominids) that refers to walking upright on two legs (as opposed to four legs as most mammals do). This leaves the hands free for exploration, carrying, tool making and manipulation of the environment.

Foramen magnum

Rift valley (Hadar region, Olduvai)

Primates (Order)

Archonta Superorder

Prosimians

Tarsiers

Insectivores

Olfactory sense

Opposable thumbs

Orbital convergence

Dental Comb

Nails and claws

Post orbital bar/plate

Omnivore

Herbivore

Frugivore

Nocturnal

Diurnal

Plesiadapiformes (Paleocene-Eocene)

Euprimates (Palecocene-Eocene)

Eosimias (45 mya)

Omomyidae (Ecocene)

Adapidae (Ecoene)

Pondaugia (44 mya)

Amphipithecus (44 mya)

Catopithecus (37 mya)

Aegyptopithecus (35-25 mya)

Miocene Apes (26-9 mya)

Proconsul

Pierolapithecus

Dryopithecus

Sivapithecus

Ouranopithecus

Gigantopithecus

Morotopithecus

Prognathism

Supraorbital torus

crenulated enamel

simian shelf