Lecture 7 - Taphonomy & PMI

What is taphonomy?

Everything that happens to a body between the time of death and time of recovery (and beyond); postmortem (PM) changes to the bone

What are the 3 main forces of taphonomy?

Human behavior, non-human animal behavior, and environmental

What does human behavior in taphonomy entail?

Dismemberment, disfiguring the corpse, PM trauma like excavation damage

What does non-human animal behavior in taphonomy entail?

Scavenging, chewing, gnawing

What does environmental forces in taphonomy entail?

Weather, water, burial (e.g. soil staining and root damage)

How can you tell rodent gnawing from cut marks?

Rodent gnawing has parallel tooth rows; especially present on long bone ends and any bone that juts out

How can you tell carnivore activity from human behavior?

Carnivore activity has puncture marks from canines, breaks, and scores/furrows

How does fire affect taphonomy?

Causes shrinking, cracking, and color changes in bones. The hotter and longer the fire burns, the whiter the bone will be

What is the main example of weather's effect on environmental taphonomy?

Sun bleaching. The longer a bone is exposed to the sun, the whiter the bone will be

How can water affect environmental taphonomy?

Algal staining (mostly green), waterlogged, abrasion

Why study taphonomy?

Position, color, weathering, and erosion of bones is consistent with where and how body was found; movement of body; elapsed time since death; and behaviors of animal, human, gravity, and water

What was the most destructive agent in Dr. H's acid study?

Muriatic acid, aka hydrochloric acid

What is the ONLY way to completely get rid of a body and denature its DNA?

Dissolve it in muriatic acid

What is the postmortem interval (PMI)?

The amound of time that has elapsed since the death of the decedent; time since death (TSD)

What is decomposition?

The breakdown/destruction of organic tissues, resulting in partial or complete loss of components of the once living body

What are some things that decomposition affected by?

Location, climate, environment, clothing, carnivores, trauma, etc

What is the simple definition of algor mortis?

Body cooling after death

Algor mortis

Dead bodies cool to ambient temperature, rate of cooling influenced by many factors, compare temperature of corpse to ambient temperature

What is the simple definition of livor mortis?

Discoloration

Livor mortis

Blood drains to low parts of the body (low depending on the postion of the body), low points skin color purple, pressure points skin color white, pattern formed when individual dies is retained (even if the body moved)

What is the simple definition of rigor mortis?

Stiffening

Rigor mortis

Muscle glycogen converts into lactic acid, and constituents coagulate as muscle becomes acidic, causing stiffening of the limbs and body

What is autolysis?

The degeneration of body tissues by the digesetive fluids normally residing in the intestinal tract

What is putrefaction?

Occurs when microorganisms normally residing in body tissue begin to proliferate and break down biological components

What is marbling?

Skin is lighter than the dark red blood in veins

Blood vessels begin to show through the skin as dark greenish-black or purple branching lines

What is blistering?

Fluid-filled sacs forming on the surface of the skin

What is skin slippage?

Outer layers of skin detaching from the underlying layer and sloughs off the body

What is discoloration?

Typically starts in abdominal area, turns yellow, green, blue and then goes darker blue, red, black

What is bloating?

Result of postmortem gas formation, making the body look inflated

What is adipocere?

Crumbly, white, waxy substance (soap). Forms in wet, unoxygenated environment

What is skeletonization?

The disappearance of most soft tissue

What is forensic entomology?

The study of insects as related to medicolegal death investigation

What is the University of Tennessee Anthropology Research Facility called and who founded it?

The Body Farm founded by Dr William Bass

What does the Body Farm do?

People donate their bodies for body decompostion research in a large variety of postmortem contexts/environments. Lots of research and training done to study how the body decomposes in different environments