Lecture 3 Flashcards
What does the traditional view of human evolution lead to?
A flase progression and therefore the missing link
What is the Piltdown man also known as?
Eoanthropus dawsoni
Who painted the painting ‘Dawn Man’ and when?
John Cooke in 1915
When was the hoax revealed?
1953
How were the bones aged on the hoax?
By staining it with iron solution and chromic acid
How were the teeth made to look more human like?
By filing them
What hoaxes were found?
Medieval human skull bones, Orangutan jaw, chimpanzee tooth, The cricket bat and stone tools
What is evolution?
A tree
The longer the line….
The further back in time or the further away genetically, depending on what is being analysed.
When did the last common ancestor of monkey and apes live?
25 million years ago
When did the last common ancestor of chimpanzees and humans live?
Between 6 and 8 million years ago and we do not yet have its remains.
What are the four sections of evolution?
Prosimians, Monkeys, Apes and a sub-section of Great Apes
Which animals are in the Prosimians?
Lemurs and Lorises and Tarsiers
Which animals are in the Monkeys?
New World and Old world monkeys
Which animals are in the Apes?
Lesser Apes
Which animals are in the Great Apes?
Orangutans, Gorillas, Chimpanzees and Bonobos and Humans
How is time estimated?
The Molecular Clock
What does the molecular clock hypothesis assume?
That the time for one neutral change in the DNA code to be replaced by another is relatively constant.
How does the mc hypothesis help us estimate time?
The number of differences between populations or species can therefore be used to estimate the passage of time.
What does the graph showing constant rate of evolution of the alpha-globin show?
That with time increases the difference in amino acids.
What does each point on the graph (alpha-globin) show?
A pair or a group of species
What happens to items in a code?
Items in code can change but the information coded stays the same
What are chromosomes made up of?
Genes and the spacer DNA between them
What are genes?
Strings of code
What is spacer DNA?
It is a string of code is not acted upon
What does it mean if there are more random mutations?
It means more time has passed
What happens if the mutation happens in a part being used?
It will cause the species to change and evolve and if it happens in a part not being used, there will be no effect
What else has evolved?
Language
Who produced the phenogram of 10 primate mitochondrial DNA sequences?
Kalinowski S T et al in Genetics 2006 (1379-1383)
What did the phenogram show?
That the greater the difference between species, the further to the left the lines are connected.
What else suggests the evolutionary relationship between apes and humans?
Skull morphology and mtDNA sequence variation
What are the different regions called in a chromosome?
Telemore and centromere
What are the telemores?
Structures at the end of each chromosome that contain repetitive DNA and serve as a protective ‘cap’
What is a centromere?
A region that binds together chromosome pairs during cell division
What does chromosome pair 2 have?
It has a telemore sequences in the middle and two centromeres indicating that it is the product of the fusing of two ancestral chromosomes.
How many chromosomes did Great Apes have?
48
How many chromosomes do Humans have?
46
How have we lost two chromosomes?
At pair 2, apes etc have two small ones and we have one large one
How many species are in the evolution tree?
275
When did Neanderthals appear and disappear?
500,000 years ago and disappeared 28,000 years ago
When was the human genome decoded?
In the year 2000
How does speciation occur?
Very gradually
When did the ancestral line diverge into species?
4.5-6 million years ago
When did the Gorilla lineage split?
6-8 million years ago
What are the three ways we can connect humans to ancestors?
Fossil records, parasites and genetic analysis
What is the difference in jaw shape between apes and humans?
In apes it is U shaped and in humans it is parabolic
What else changed in a human’s mouth?
The large canine teeth disappeared, diastema disappeared, pre-molars and molars have small cusps and incisors are small
What changed in the diet 3.5 million years ago?
There was a large increase of grasses and sedges
How are questions about food eaten by fossil species informed?
Tooth size/wear, Jaw size/shape and chemical composition
How are questions about habit informed?
By knowledge of environments where those food types are found today
Where are sedge varieties found?
In wetland or damp environments
What other proof is there about food?
That it was processed before being eaten by use of stone tools, cooking or both
Why did the crest on the top of the head appear?
Because muscles join at the top of the skull and jaw is very powerful
Where is the foramen magnum located in humans and where was it located in apes?
In the middle of the skull and in chimpanzees at the back
Why does the foramen magnum need to be in the middle?
Because we are not on all fours, we walk upwards so if it was at the back, it would mean we couldn’t hold our head up
Why has our musculature changed?
Because we are upright and so we need to have support from the glutes so that we don’t rock side to side and don’t fall forward
What shape is the human’s spine?
Curved S-spine and the vertebrae wedge shaped in consequence.
How long have we been bipedal?
3 and a half million years
What percentage of births are done by caesarean in the developed world?
22-28%
Where medical help is not available, how many women die in childbirth and how many suffer severe soft tissue damage?
1 in 7
How many birth-related neonatal deaths are there?
42-49 per 1000
How much bigger are human infants than the birth canal?
2%
What does the shape of human’s spine mean for birth?
It means that the mother cannot help her child be born
What path did the homo erectus take and what are they also known as?
Africa, India, China and Dnamisi
What evidence do we have for things they developed?
Stone tools, seafarers and first evidence of use of fire and cooking
What are archaic homo sapiens known as?
Homo heidelbergensis
What did archaic homo sapiens achieve?
Routinely butchered large animals, fossil records suggesting they used hand axes and built shelters
What percentage of Neanderthal Genome lives on in humans?
20%
Who was to the west and east of the Caspian sea?
Neanderthals were to the west and the Denisovans were to the east but there is inferential evidence for a third species
When was there last recorded Neanderthal activity and where?
30,000 years ago in the Southern Iberian peninsular
When were homo floresiensis last around?
50,000 years ago
What did homo floresiensis live amongst?
Elephants and large birds
What happens if they are below 30kg?
They get bigger and above, smaller
What does the modern human tree based in nuclear DNA products indicate?
The distances idnicate a 100,000 year time scale
When did modern human migration out of Africa start?
100,000 years ago with successive waves after that
What are the two routes out of Africa?
Northern route into the Levant and the Southern route across the ‘gates of tears’
How many episodes of limited gene flow were there?
Two
What was the first episode of limited gene flow?
Genetic admixture from Neanderthals to modern humans shortly after the exit from Africa
What was the second episode of limited gene flow?
Subsequent admixture with the archaic population exemplified by the nuclear DNA extracted from the Denisova finger bone.
Which of the parasites did we contract from our ancestry?
Tapeworm, malaria and louse
What is tapeworm called in beef, pork and fish?
Beef = Taenia saginata, Pork = Taenia Solium, Fish = Diphyllobothrium Latum
What is tapeworm normally linked to?
Domesticated animals but we actually gave it to them
Where did human malarial parasite come from?
Gorillas
What percentage malaria cases is the plasmodium species responsible for?
85%
Where do 90% of the malarial deaths occur?
Sahara desert and in children under 5
What three types of louse are there?
Head, Pubic and Body
When did body louse occur and why?
We’ve been wearing clothes for 100-150,000 years so that is when it occurred because they need something to live in.
How long were Gorillas living alongside humans?
3 million years
How long have recognisably human-like species been around?
2 million years
What percentage Neanderthal is everyone in the world?
Somewhere between 1-6%
What do fossil records suggest for our origins?
East Africa
What do the parasite records suggest for our origins?
East Africa
