Domestication Quiz 2

commensalism

co-evolutionary relationship beneficial to one species

mutualism

co-evolutionary relationship beneficial to both species

village cat theory

human-cat relationship mutualistic, humans get rodent control, gets get food

colonies

feral domesticated cats, lions, live in groups

solitary

bobcats, sand cats, Felis silvestris libyca

Shillourokambus, Cyprus

cat burial ~9500 years ago

first domesticated cats

six cats (male, female, and 4 kittens) buried in Hierankonpolis ~5700 years ago

material culture

physical remains of past human activities such as artifacts, ecofacts, built environments, and landscapes

context

spatial relationship between elements that allow interpretations of human behavior

archaeological site

any place where material evidence exists about the human past

taphonomy

laws of burial

stratigraphy

sequence of soil and sediment layers below ground

relative dating

data expressed the same, older, or younger than something else by association

absolute dating

data expressed in units of time (years ago)

radiocarbon dating

measures time since death, living organism takes in C14 which decays to radioactive C12 after death

paleoethnobotany

ancient plant remains associated with archaeological sites and/or paleoenvironments inhabited by people

macrobotanical

fragments of plant material (usually charred), can be seen with human eye

microbotanical

pollen, starch, phytoliths

method for recovering remains from sites with ordinary preservation

look for carbonized (burned) plant remains

flotation

method for collecting ancient plant remains, remains are less dense than water and sediment sinks

comparative collection

collection of modern plants to compare and identify plant fragments

likely region of finger millet domestication

Kakapel, Kenya

result of finger millet investigation

it is easy to differentiate between wild and small domesticated finger millet on the basis of shape

Eastern Agricultural Complex

Late Archaic, Woodland, Mississippian in woodlands of eastern US

How to know crops are lost?

human paleofeces

documenting domestication

look for non-shattering, greater size, loss/reduction of germination inhibitors, loss/reduction of glumes or other appendages

characteristics of domesticated erect knotweed (Polygonum erectum subsp. watsoniae)

larger seeds, reduced average pericarp thickness (protection), greatly reduced seed dimorphism in favor of seeds with less protection

paleoecology

reconstructing past ecosystmes

unconscious selection

used to describe everything people do that effects plant and animal evolution other than formal breeding, does not mean acting without any goal in mind

conscious/directed selection

breeding or cloning with predetermined goal in mind

pollen

contains male gametes of flowering plants, most useful for environmental reconstruction

example of systematic bias

wind pollinated species likely to be overrepresented

pollen can easily move around in the soil so it …

must be taken from special contexts like lake cores or buried soils

phytoliths

opaline silica (glass) bodies that form around plant cells, inorganic

problems with phytoliths

cannot be directly dated, formation processes and function in plants are still poorly understood

results from Denham et al 2003

phytoliths show increase in banana and grass over time, pollen shows decrease during periods of fire and then herbaceous plants remaining

starchy plants

some not well represented by their seeds but can find starch instead

problems with starch

size and shape effected by heat and moisture

found on worked edge of stone tools from Denham et al

taro starch grains

landscape domestication

“…human manipulation of the landscape results in changes in ecology ….” Charles Clement

location of many domesticated landscapes

Amazon

zooarchaeology

faunal analysis, subfield of archaeology concerned with animal remains from archaeological sites

zooarchaeology includes analysis of …

ecofacts and artifacts

ecofacts

animal body parts, mostly bones

artifacts

tools and artwork made from animal products

skeletal element

identifies which bone, some preserve better than others

taxon

identifies which animal, often cannot identify exact species

minimum number of individuals (MNI)

counts best represented skeletal element (3 left thigh and 2 right thigh, MNI = 3)

number of identified specimen (NISP)

counts all fragments as individual specimen (85 pieces of antelope)

documenting domestication

involves domestication pathways: commensal, prey, directed, tamed captives, or experimentsc

commensal domesticates

eat human garbage or eat animals that eat human garbage

prey domesticates

game management evolves into herd management, likely path of most livestock

demographics of hunting population

adult males overrepresented, adult females and sub-adults of both sexes also present

demographics of herding population

sub-adult males and older females are overrepresented, sub-adult and young adult females and adult males underrepresented

prey pathway method

sex-specific age curves

sex-specific age curves: age

epiphyseal fusion, morphometrics (size and shape), tooth eruption and wear (more enamel worn away)

epiphysis

“cap” on the end of developing bone before it fuses

sex-specific age curves: sex

sexual dimorphism, muscle attachments (pelvis)

prey pathway case study

Goats (Caprus hircus) in the Zagros Mountains 10,000 years ago (Zeder and Hesse 2000)

Ganj Dareh

site of earliest evidence of goat domestication

reduction in bone size at Ganj Dareh due to demographic difference

hunting profile (only contains large adults), bi-modal distribution made of many sub-adult males and a few older females, existance of contemporaneous lowland herd with size reduction and herd demographics

survivorship curve

survivorship decreases

directed domesticates

always secondary, use knowledge gained from management of domesticated animals to domesticate new ones

directed pathway case study

Where, when, how, an why were horses (Equus caballus) domesticated?

Botai

early site of possible horse herding, 99% of bones from horses, coral structure

methods of investigation at Botai

morphometrics (smaller than extinct wild progenitor), cultural bone modification, residue analysis (drinking horse milk), analysis of skeletal evidence

the schlepp effect

hunters leave heavy bones at kill size, results in different skeletal elements at kill sites vs. habitations for hunted animals, herded animal bones end up in garbage

Botai conclusions

directed pathway to domestication, used for meat, milk, and transportation, neatly fits timeline for movements across Eurasia, provided precedent for obviously domesticated horses of Bronze Age

Botai problems

sex-specific age curves do not exhibit bimodal distribution that managed herd should (dominated by sub-adult males and older adult females), instead even split between males and females mostly of reproductive age

descendants of Botai horses

Przewalski’s horses

mass harvesting of wild horses

group hunting results in all-mare or all-bachelor kills which yields even demographic split, near landscape trap or river

isotope

two or more forms of same element that contain different numbers of neutrons in nucleus

stable isotopes

do not decay so not used for dating, tell something about environment organism lived in

stable isotope applications

paleoenvironmental reconstruction, food web analysis

fractionation

any process that results in differential transfer of heavy isotope

δ

expressed parts per thousand difference from a standard

how oxygen is used to track global changes in climate

glaciation traps light oxygen in ice removing it from bodies of water, oceans and lakes enriched with heavy oxygen as glaciers expand, becomes traps in marine shells in calcium carbonate

heavy isotope

contains extra neutron

food web analysis

tells who eats who

trophic level

number of steps removed an organism is from bottom of food chain

heavy nitrogen and carbon

enriched at every trophic level

marine food complication

variability in nitrogen isotope has complex origins due to fixation and release, marine ecosystems enriched for N15 compared to terrestrial ones at each trophic level

equifinality

same effect can result from different events

C3 photosynthesis

simpler but less efficient photosynthetic process used by majority of plants

C4 and CAM photosynthesis

more complex process that allows photosynthesis to continue in hot and dry conditions, most are tropical grasses

carbon fixation

process by which plants turn inorganic CO2 into organic sugars, base of food chain

carbon fixation leads to stable isotope fractionation

C4 plants integrate more heavy carbon into their sugars than C3 plants

C4 plants derived from tropical grasses

maize, foxtail, broomcorn, pearl, and finger millets, sorghum, sugar cane

selection

acts on parts of genome that effect phenotypes that effect fitness under particular conditions, study domestication by teasing out these signals from those of other kinds of evolutionary change

HW Equilibrium

genetic variation in population will remain constant from one generation to the next in the absence of disturbing factors, idealized state

why evolution is always ocurring

impossible for all assumptions of HW equilibrium to be met in real life

genetic drift

change in frequency of a variant that is due to random chance

cost of domestication

founder effects and bottlenecks

genetic load

accumulation of deleterious (not helpful) but non-lethal alleles that leads to a reduction in fitness

gene flow

movement of genetic material between populations, from progenitors or other domesticated populations

polyploidy

heritable condition of possessing more than 2 complete sets of chromosomes

connections between genotypic and phenotypic change

top down or bottom up

top down

start with phenotype of interest, breed segregating populations, conduct genomic mapping, find regions that differ

bottom up

look for signature of uneven selection in genome, try to figure out what those regions are doing

model species

species extensively studied to understand basic biological phenomena