multiple choice, short answer, fill in the blank and definitions.
5 most important aspects of human evolution
- Variation already exists in a population
- Survival of the fittest
- Natural selection ***
- Sexual selection
- Descent with Modification ask for what this is
Who does evolution act upon? Upon population as a whole
- A group of creatures which breed together and produce viable and fertile offspring
- May be similar in appearance (deer) or variable (dogs - poodles and chihwahwa can produce offspring)
- May all live in one part of the world (polar bears) or in many parts of the world (right whales)
- Share behavioral traits relatingto social groups, food preferences, reproductive strategies, etc.
- Species have a shared behavioral and social grouping, meeting, eating, etc.
- Distinguish between members of own species and others
o i.e. Giraffes – ones from different places wont mate although they are same species, because they have different mating ritual.
- Natural Selection
- Human Origin in Decedents of Men.
- Genesis - 6 days
- The technology they had after they got kicked out of Garden – they learned how to deal with metal or iron etc. this will be important in
learning tools and humans
History of Origin
- ArchBishop Ussher 1650AD
- Origin of the Earth and therefore humans based on his interpretation of the bible
- Analyzed bible for age of earth
- The world must be 4004 B.C. on October 23 . rd
- Georgy Cuvier
o If only 6000 years old, then global and violent catastrophes to explain canyons, mountains o He started to notice that there is constant change –rivers are eroding cannons.
o A thing like mountain building was thru the idea of catastrophe.
o This was one point of view during enlightenment period.
- Burnet (1681AD)
o He started to focus that there is also slow erosion by water, wind, and ice
- Buffon 1749 AD
o “to learn about the earth, study the earth” – processes are known, natural, and observable
o He had to retract the statement for being fear of persecuted.
- Hutton (1788AD)
o Said the same thing but it has to be hundreds of thousands of years old, not just 6 days. He said the earth was slow working,
uniform, and natural processes
o After 100 years after Hutton, he said earth had to be at least 100 000 years old by saying “present is the key to the past”
o Maybe it was Ussher that was wrong, not the bible.
- Comparative biology
- He categorized humans amongst animals by calling us Homo sapiens.
- He tried to do it to worship God but he invertly classified humans as animals.
- 7 basic layers or taxon levels
o kingdom, phylum, class, order, family, genus, species
- Binomal system
- Homo Sapien (wise man)
- Species arms. You can see that they all have primitive pattern in arms. They all have single armbone. The top right bone belongs to a
Conclusion of Enlightenment Period
- People accepted it and rejected bible. It was the conclusion of Enlightenment period
o Extinct animals
o Strata and stratigraphy
1 evolutionary theory
- Lamark came up with the idea.
o Inheritance of acquired characteristics wrong
o Progression towards perfection (like giraffe got long neck due to reaching far for trees) wrong
o Adaptation to environments right
- There was this idea of perceived final goal.
- Variation already exists between individuals of the same species that allows for adaptation to changing environment
- Coincidentally better adapted to an environment = higher reproductive success
- This increases this trait within the species
- Variation is RANDOM with NO DIRECTION
- Mechanism of evolution = natural selection ***
On the Origin of Species 1859
- If a population of geographically separated and reproductively isolated, the different population will be exposed to different population
- As changes are selected over time, they MAY become 2 different species
o Humans never separated into different species, just race. This is where things might change in future.
- Grant and Grant 2002
o Existing variation
o With no direction
- Darwin didn’t even recognize that all was same species, but he recognized that finches looked very different based on morphology of
beak (related to diet)
o Wiped insect.
o The finches didn’t have small beaks but to open seeds.
o They already had capacity of opening seeds but they could feed themselves better after the draught.
- Rain returned
o Insects returned
o The new generation started having small insect-sized beaks again - Change depends on environment
- Change works on the trait variation already present in a population
- No direction
- Crossbreed. 3:1
- He found that traits in offspring are not either passed solely by either parent. Traits are passed in small, independent genes from both
o Different variation of genes
o It can be eye colors but there will be different alleles for eye color.
- Independent assortment
o Just because you have dominant genes it doesn’t mean it will be passed on more.
o Recessive genes will as much as dominant genes will
- Homozygous state: for a given trait, individual receives the same gene form from parents. Green and green
- Heterozygous state: individual receives 2 diff genes from parents. Green and yellow
- The whole set of diff forms for a given gene is known as alleles.
o Sometimes the yellow allele was expressed (appeared in the plant)
o Sometimes the green allele wasexpressed
- Dominant gene – always expressed in the individual who carries them such as green peas
- Recessive gene – expressed only if they are homozygous (if no dominant gene is present)
Terms on your midterm ***
- Genotype: all genes in an individual. Genotype represents our real genetic structure or DNA
- Phenotype: the visible individual
o If you paint your nails or dye your hair
o The expression of genetic dominance
o Physical changes caused by events in the individual’s life
- Genome: the entire range of alleles in a species; the gene pool
- Most physical traits represent complex associations of several diff genes
o Gene complexes often include genes on completely diff chromosomes
o Some genes can be co-dominant – blend together rather than dominating or submitting (hair color)
o Sometimes the nature of one gene determines the dominance or recessively of another
- Non-metric traits
- Darwin’s tubercle
- Hair whorl direction
- Thumb dominance
- Tongue curling
- Earlobes attached
- Fingers same length
What causes new traits?
- Changes in genes
- Changes in chromosomes
- New complexes or combinations between genes
3 processes of evolution ***
- Mutation – the only direct way in creating new alleles - Gene flow
- Genetic drift
- Advantageous, deleterious or neutral
- Random mechanical errors during DNA synthesis – sickle cell anemia
o Can be good, bad, or neutral.
o Sick cell anemia = neutral.
o Homozygous state: most individual doesn’t make to reproductive age = bad
o Heterozygous state: cell doesn’t deter completely and prevents malaria from entering the body = good
- Chemical pollution
- Cosmic nuclear radiation
- Individual demes – fission
- Founder effect
o In a small population, there may be only a few individuals who possess a particular genes
If these individual don’t have offspring, that gene is lost from the gene poll of that population
o In a small population, everyone is closely related, in-bred
Mutations spread quickly though the population
Easy for a mutated form to become “the norm” i.e. Bad mutation can become the norm
- Opposite from above
- If people split into demes, separate breeding populations they will have undergone some natural selection
- If 2 demes start to interbreed, then new genetic material is introduced or flows into both gene pools
- Offspring will have new genetic combinations
- Gene flow acts to homogenize populations, preventing speciation
Theories of speciation (how species develop)
o All populations are changing all the time, gradually changing into new forms and forming new species
- Punctuated equilibrium
o Stable population goes through catastrophic change rapid change and produce new species adaptive radiation
- Many species have status quo
- No need to change because they are perfectly adapted.
- Morphology and Time
Humans are primates
- Forward facing eyes
- Opposable thumb – grasp
- Most live in tree – arboreal. So we will look in trees when looking for fossils
- Large brain size relative to body size ***
- Infant dependency – humans are unique that they have childhood
- Manipulate the arboreal environment thru grasping and dexterous hands and feet
What are main primate groups?
o Lemus, Lorises, Tarsiers NW
o Apes, Humans OW
- We are not evolved from apes, we ARE apes.
Similarity between apes and us
- 2:1:2:3 dental structure
- Large body size
- Large brain size
Classification schemes for primates
o Linnean style
o Similarities, and differences
o Old way of doing it
- Cladistics o New way of doing it
o Through shared derived traits – it is shared because we have common ancestor.
o Similar trait shared by 2+ species but unrelated evolutionarily; convergence
o The wings of a bat and butterfly = different ancestor but same way of dealing w environments.
o Similar trait shared by 2+ species thru inheritance from a common ancestor
o Pattern of long arm bone then 2 forearm bones
“Eve” Cann et al 1987
- Origin of Human species
o Genetic studies on modern populations
o mtDNA high mutation rate, follows female lineages
o Variation was highest in African women - mutated more often than other groups
o Standard rate of mutation at 2 to 4% per million years
o Africa is the origin of Homo sapiens and been around 200,000 years ago ***
Krings et al 1997
- Same species?
- Neanderthal DNA
o mtDNA from the type specimen
o Compared to modern humans
o Outside the range of variation o Mutation rates place divergence from homo sapiens at 300 to 800,000 years ago
o Therefore no admixture
- They managed to amplify the DNA samples they have and compared to humans.
- Problem of the study
o There is only one sample to represent all the population.
o Using that same clock suggested that this shared ancestors with human beings 300-800,000 years ago. This means no
admixture because Homo sapiens was around for only 200 000 yrs.
- You have to be aware of individual bias including your own
- He guided chronological ideas in terms of identifying the sample age
- Homo Hablis
o They are not talking about giant swings of time. Why is it so important that it was older than 2 million years ago?
o In their minds, it was one of the early specimens. If it were younger than Homo Erectus then of course you would want your
sample to be younger.
- What are 2 competing main methods to date methods in Tuff Break?
o Argon-Argon/Potassium-Argon dating
o Pig teeth method
- In the past we had to reply on these methods but there has been 2 things that have been discoveries that transformed the way we think
o Nuclear physics – the fact that some elements have different radio reactivity
o Construction of mass spectrometers – they isolate beam of particular atom and bend. If this is a beam of carbon, it will bend
on different degrees because they have different atomic rates. It will measure the actual number.
South and East Africa
- We have evidence that bipedalism started not in savanna necessarily but more in the tropical forests.
- East Africa
o the giant geology
o 4-5 million years old sediments.
- South Africa
o Mine sites
o Only through the active tunneling deep into the earth will get us one.
- Archeological visibility ***
2 different archeological sites
- Open site:
o best thing is that it represents single event or occupation.
o It is easy to radio activate.
o Palimpsest 다층적
- Cave site/rock shelter:
o Cluster formation of cave.
o Rock shelter is it looks like cave but not.
How do we find sites?
- Morphological features
o Sources of water, firewood, etc. lead to shelter
- Field survey
o Surface walking
o Subsurface investigations
Electrical resistivity survey
Ground penetrating radar
o Random testing
- Relative dating methods
- Absolute dating
o Radiocarbon (C14)
o Potassium-argon (K-Ar)
o OSL (Optically Stimulated Luminescence)
Stratigraphy at Sehonghong
- Site A
o Layer 1 – small blades
o Layer 2 – scrapers o Layer 3 – adzes (C14 1000+- 50 BP)
o Layer 4 – large blades
o Layer 5 – Handaxes
o Layer 6 – No tools
- Site B
o Layer 1 – small blades
o Layer 2 – Adzes
o Layer 3 – no tools
- Therefore Layer 2 in Site B probably dates to around 1000 +- 50 BP
- You find a sample in one site and same thing in the other site, they should be the same age.
- What are 2 major things that can cause sediments to move around?
o Burrowing animals
o Water – water table can rise. When yellow and black sediments are mixed, they turn grey
Radiocarbon dating C14
- All forms of life contain carbon
o So does food that organisms eat everyday
o Living organisms constantly replenish C14 atoms through the food chain
- Carbon exists in 3 forms or isotopes:
o Carbon 12 is common and stable (99%)
o Carbon 13 is rare and stable (<1%)
o Carbon 14 is very rare and radioactive - decaying
- The proportion of 12C to 13C isconstant through the living world. 14C begin to decay (slowly) into N14
- C14 atoms have a half-life of 5,730 years
- C3 tree
- C4 tropical (has more C13)
- Northern hemisphere: INTCAL09
- Southern hemisphere: SHCAL04
- Marine: MARINE09 +DeltaR
- Mixed feeder: need to know %marine protein
- Calibration programs: OXCAL 4.1 or CALIB 5.0
- Every year there is variability in solar flares. So there is no constant ratio, it fluctuates. You have to take that into account.
- Computer will do it for you. - We have plants in the mixed layer of the ocean but sometimes, esp in cold region, there is thermo-healing circulation.
o Cold water in Polar Regions sink to deep ocean, taking that carbon with it.
o Rather than coming back up, it gets trapped in Reservoir *** in the deep ocean so there is old carbon problem.
o It continues to decay in the deep ocean then eventually it comes back up to the surface. Old water comes to surface and mix
with surface water.
o This means if you were to go to the ocean today, it wouldn’t say its today old but it is 400-500 years old (old carbon).
o That is what Marine Curve does.
- Apply a marine curve – it is very important
Potassium-Argon dating (K-Ar Dating)
- Potassium 40 (radioactive solid) decays into Argon 40 (inert gas)
- Works only in volcanic or monomorphic scenarios
- When a volcano erupts, the hot lava releases all gases, including Argon.
- Thus, all Argon 40 found in a lump of cooled lava is the product of radioactice decay of Potassium 40 in the original lava
- 100,000 to 2 billion years ago
- P40, which is radioactive solid, will decay.
- When volcano erupts it will only have P40
- If you know how old the bottom and top layers are, you know how much the middle one is.
OSL – Optically Stimulated Luminescence
- As opposed to organic materials or lava, OSL is used to date Quartz Crystals
- When buried, qtz crystals absorb radiation from surrounding rocks (crystal lattice)
- Optically stimulate the crystal and measure the amount of radiation emitted
- Know how long the quartz wasburied, or at least the last time it was exposed to sunlight
- Must also know the local DOSE rate
- A few hundred years ago 100,000 years ago
- Cristal has imperfection in itself. When you bury corpse, it trap electrocals. If you are careful and collect samples of these quartz crystal
(sample) in a dark room before you get to the lab, they will release all electrites they captured. You can easily work out the ratio.
- Thermo luminescence – what are they doing? They are relying on heating of the quartz. This is why TL works on burnt things
- In both cases you need sample of dose rate of that rock.
- Oxygen– temperature
- Carbon and nitrogen – vegetation
- Palynology – vegetation
- Faunal (animal) remains – local ecology
Oxygen isotopes (C16/O18)
- Indicator of temperature
o O16 bonds with ice (rare)
o O18 bonds with water (common)
- Left chart: constant deposition. This introduces error because some winter can be colder than other.
- Middle chart:
o X axis shows whether O16 is redundant or lacking
o Y axis time
o Find today. It crosses X on -2.25. Earth has been warming for the past 1000 years.
o Odd numbers = warm
o Even number = cold Stable Isotopes of C and N
- Carbon differentiates between
o C3 and C4 plants OR
C3 plants = trees and bushes.
C4 plants are tropical plants.
Grass are recent.
o Terrestrials and Marine protein
- So we can use this C and N to find out when grass appeared.
- We can use same scale, but only when there are no C4 plants.
- They have same signature so it is hard to differentiate the 2.
- We are lucky that the plants, trees, and bushes use 3 molecules to photosynthesize carbon.
- In Nitrogen, we find trophic level.
o Delta (difference between) depending on environment it is selected for or against.
o Unite: “per mil”. - We get the value (range between -33 and -21)
- But C4 pathways range from -7 and -15 so we say the average is -12.
- These 2 do not overlap so this is method available to us
- It is always negative because it was standardized against what is not negative.
- As carbon moved thru the food chain, we see Fractionation.
o If a rabbit eats plants, carbon will lay in its bones but the ratio is shifted (fractionation).
o 5 mil per stage.
o This is why it will show -21 or so.
o Rabbit that eats nothing but tropical plants will only have -5.
o But if the rabbit eats both, it will be somewhere in between. This gets complicated.
- Fractionation works differently in different parts of the body.
- The group on the top (in the graph after this)
o individuals that don’t eat corns but salmons, they will have both high nitrogen and carbon.
o Then you can find out their diet. Human Origins
- Must look at the earliest members of our Order – Primates.
- Primate? (how we distinguish whether the fossil is primate or not)
o Opposable thumb
o Infant dependency
o Stereoscopic vision and vision is the dominant sense (dogs –smell)
o Large brain relative to body size
Models of associated behavior
o The idea that things behave the way we do today cuz of the they did in the past
- Parsimony or Occam’s razor
o If there are many explanations, usually the simplest one is the right one.
o Doesn’t necessarily mean it is right though
General definition of Primates
- Arboreal mammals (adaptation to live in trees)
- Vision-dominated senses (no focus on smell)
- Large complex brain to body size
- Complex social organization
- Long gestation and infant dependency
- Typically one young per pregnancy
- Manipulate an arboreal environment through grasping and dexterous hands and feet
Fossils – bones and teeth
How are we going to use these fossils to distinguish them to be primate vs. dogs or cat? ***
o Post orbital bar
Primates need bone things to protect their eyeballs because it is the dominant sense, whereas dogs nose is dominant
o Eyes forward
o Sagittal crest
o Nails instead of claws
o Opposable thumbs/toes
- Another category
o Large skull to body
- Grasping foot with divergent Hallux (thumb)
- Presence of nail on Hallux and most other digits
- Elongation of the heel
- Dominance of hindlimb duringlocomotion
- 5 digits on the fore and hind limbs with opposable thumbs and big toes (Hallux)
- Tactile pads on end of digits
- A complex visual system with
stereoscopic vision, high visual acuity, and colour
- Orbits encircles with bone – bar or fully
- Reduced number of teeth compared to
- Trend number of teeth compared to
- Trend toward holding the torso upright
- Retention of the collar bones
- 2 mammary glands We are from Lagomorpha
- They share almost identical morphology
- They are directly related to functional behavior and loco-motion (how they move around on land)
- Be comfortable with different dentition and what they represent
- Humans have thicker enamel
- Directly related to enamel – we need to know how thick it was
- Shape of the teeth
o Left dental shape
Unlikely to be on human lineage
Cusps are tall and sharp because they tend to eat things like grass and insects they need to sheer thru them
o Right dental shape
Low rounded cusps
Apes, human lineage
o How what they eat affects their teeth
o A – monkey – deep pits in enamel
o B – homo erectus
o C – homo hatelus (sp?)
o D – they have scratch marks on enamel
o We can study their diet depending on their enamel
Inferring body size from diet
- We can usually associate body size depending on diet.
- At the top there is ratio of browsers and grasser ***
o C4 eaters: Browsers eat trees and bushes
o C3 eaters: Grassers eat grass
- Insectivore tends to be very small.
- We use modern primates to interpret the past PALEOCENE/EOCENE
Adaptive radiation – when newhabitat comes up it spreads
Strepsirrhini – wet nosed primates Haplorrhini – dry nose primates
- Rhinarium (dominated by sense of smell) - No rhinarium
- The most primitive - Post-orbital plate Orbit is now bony support being
- Post-orbital bar invested in those eyes