ANTHP105 Exam 1

four branches of anthropology

Archeology

Biology (physical)

Cultural

Linguistic

Biological anthropology

study of human/primate biological variation

Five branches of biological anthropology

Forensic anthro

Genetics

Human Bio

Paleoanthro

Primatology

Human Biology

Study of contemporary human biological variation

Scientific method

Observation → Hypothesis formation → Hypothesis testing → theory development

Three branches of testing ideas + respective inputs

Exploration and discovery: inspiration from individual scientist

Community analysis and feedback: input from scientific community

Benefits and outcomes: input from government/broader society

Thomas Morgan

Nucleocentric view: genes located in the nucleus control the cell

E.E. Just

Believed cytoplasmic contents controlled the cell

Eukaryotic vs Prokaryotic cell

Eukaryotic contains nucleus and mitochondria is made of mtDNA; prokaryotic contains no nucleus or mitochondria

Epigenetics

study of chemical modifications on DNA gene expression

Steps of mitosis

1. Denaturation

2. Annealing

3. Extension

Three mechanisms for producing genetic variation

1. Mutation

2. Random assortment (during meiosis 1)

3. Recombination (crossing over)

Mendel founded which two principles of inheritance?

• Segregation: organisms inherit two alleles/gene, one from each parent.

• Independent assortment: alleles of separate traits are passed on to offspring independently of one another

Simple trait

variations are controlled by different versions of a single gene

Complex trait

influenced by multiple genes or environmental factors

Human genome project discoveries

1. Humans have fewer genes than expected

2. Most of our DNA consists of non-coding sequences

3. Most of our traits are complex

Polygenic trait

Traits in which multiple genes produce a singular phenotype

Why is sex a complex trait

it is influenced by multiple genes and the environment

Determinants of biological sex

1) presence of Y chromosome, and

2) presence of SRY gene; if absent but Y chromosome present, organism is female

3) Genes controling sex steroid receptors

Examples of epigenetic marks (chemical modifications)

DNA methylation

Histone modification (unwinding)

MicroRNA

Plasticity

individual’s ability to respond to environment by changing their physiology

Developmental plasticity

plasticity during developmental stage; results in change of adult phenotype

Dutch Hunger Winter

Malnourished mothers produced offspring w/ greater T2 diabetes risk due to epigenetic changes

Species concept

group of organisms that can interbreed and produce fertile offspring

taxonomy

method for classifying plants and animals via binomial nomenclature (genus species); developed by Linnaeus

erasmus darwin theory

members of the same species are descendants of a common ancestor

Lamarckism (incorrect theory)

acquired characteristics are inherited; ex. long necks of giraffes

Cuvier’s extinction theory

natural disasters kill most species in an area where neighboring organisms will repopulate the region; catastophism

Lyell’s uniformitarianism theory

geological processes seen today must have also acted in the past; ex. rocks

Malthus’ theory of population growth

rate of population increase > resources available; pt of crisis when proportional

Charles Darwin’s finches conclusions

all finches of a population descended from a common ancestor

population phenotypes change overtime

Evolution

change in gene frequencies of a population over time

Wallace’s discoveries

there is an environmental influence on species

evolution is driven by competition and a struggle for existence

Patrick matthew

believed in natural selection through observing trees

Al-Jahiz

describes natural selection through observing that animals adapt different traits to survive in their environment

Malthusian competition

geometric population growth, limited resources

Modern synthesis of evolution

change in allele frequencies over time

Four forces of evolution

natural selection

genetic drift

gene flow

mutation

population size effect on genetic drift

large population → weak effect on gene frequencies

small population → strong effect on gene frequencies

Tay-Sachs disease is a result of

genetic drift; HEXA gene is mutated upon historical isolation

Founder effect

form of genetic drift

gene flow

exchange of genes btwn two populations; neutral evolution

Selectionist hypothesis

most genetic variation is due to natural selection

neutral theory

most variation does not effect fitness; evolution is explained by random processes

Kimura’s observation

supports neutral theory; most mutations are neutral

biological species concept

groups of individuals capable of breeding

recognition species concept

ability of a species to identify other members of their species for mating purposes

ecological species concept

habitat/environment dictated

Phylogenetic species concept

species based on parental patterns of ancestry

speciation

formation of new species; allopatric, parapatric, or sympatric

allopatric speciation

reproductive isolation

parapatric speciation

partial geographic separation

sympatric speciation

within population

Phyletic gradualism

evolutionary change over time; transitional differences w/ missing links (fossil records)

Punctuated equillibrium

evolutionary change w/ periods of stasis (balance) w/ spurts of speciation; gaps w/ no missing links

Homologies

similarities between organisms due to descent from a common ancestor

Analogies

similarities btwn organisms based on common function; no common ancestry assumed

Ancestral trait

shared by 2+ organisms b/c it was inherited from a common ancestor

Derived trait

trait that evolved in a lineage and differs from the common ancestor

intraspecific variation

differences among individuals of same species; ex. sexual dimorphism

interspecific variation

differences between different species; ex. teeth/bone structure

Vertebrae evolution

Paleozoic → Mesozoic (non-avian dinosaurs disappear) → cenozoic (age of mammals)

Chicxulub impact

“big bang” made dinosaurs extinct; only tiny mammals survived

mammalian adaptive radiation

burst of diversity

Mammalian characteristics

• body hair/fur

• long gestation period + live birth

• mammary glands

• heterodont

• endothermy

• increased brain size

Common ancestor of all primates

Plesiadapiformes; lived ~60mil yrs ago

ancestral traits of primates

• body hair

• mammary glands

• heterodont

• endothermy

derived traits of primates

• erect posture

• prehensile; thumbs + big toes, nails, pads

• long gestational period

• bigger brain size

• forward facing eyes

• social skills

Hominin ancestry

Hominoid → Hominid → hominin

last common ancestor of humans (hominin)

Human chimp; lived 6 mil yrs ago

human-chimp traits

• chimp sized brain and body

• long limbs for foraging/grasping

• large canines; sexually dimorphic

• quadrupedal

• herbivores mostly

early hominins

sahelanthropus tchadensis, ardipithecus ramidus

bipedalism adaptations

• shorter pelvis

• foragen magnum farther underneath skull

• femur angled inward

• big toe enlarged

Genus australopithecus

exhibited bipedalism adaptations

Australopithecus afarensis (lucy)

• big toe

• shorter pelvis

• inward femur

paranthropus (robust australopithecus)

• jaw developed for higher fiber diet

homo habilis

first hominins to use stone tools

homo erectus

brain size overlaps w modern humans

Premodern humans + features

archaic H. sapiens; includes neanderthals

• thick skull, prominent brow ridges, lack of chin

neanderthals compared to humans

larger brain capacity, but shorter stature

cranial capacity + human energy consumption for brain

volume of cranium interior; 400kcal/day

larger bodies are ___ metabollicaly efficient

more

Kleibers relationship for mammals

body mass is proportional to metabolic rate

Allometry

change in size of one biological measure w/ respect to the body size

resting metabolic rate

energy consumed largely by brain, but includes other organs

human brains have ___ brain mass than expected, based on body mass

larger

Ways humans adapt to high energy cost of brain metabolism

• high quality diet

• reduced gut size

• reduced muscle mass

• altricial newborns; brain grows rapidly after birth

• babies have high body fat %