Domain: EukaryaKingdom: AnimaliaPhylum: ChordataClass: MammaliaOrder: PrimatesFamily: HominidaeGenus: HomoSpecies: H. sapiensHuman Evolution-Human and chimp DNA are ~ 98% similar. -Gene duplications make up most of the differences.-30% of human and chimpanzee proteins are identical . -The other proteins differ in only about 2 amino acids.-The differences that make us human may be largely regulatory genes or DNA in the “dark matter” of the genome.-46 Human Chromosomes (Haploid # 23)-48 Chimp Chromosomes (Haploid #24)-Fusion of ancestral 2A & 2B chromosomes to form human chromosome 2-Fusion of 2A & 2B without loss of a single geneWhat makes us human?-Primate Hand-Development of Opposable Thumb & Grasping Hand-Power grip-Precision grip-Upright posture/bipedalism-Frees hands for manipulation & carrying-Large complex brain-Development of the cerebral hemispheres- Increased Intelligence-Tool use, fire -Non-Primates-Finch on Galapagos uses cactus needles-Sea otters use rocks-Elephants use sticks-Egyptian Vultures use rocks-Australian octopus uses coconuts for shelter-In Non-human Primates-Chimpanzees -Sticks for termite fishing-Leaves as sponges-Sticks as clubs & spears-Orangutans-Leaves as umbrellas-Weave straw into rope swing-In HumansAustalopithicus ? (Some evidence)Homo habilis-Stone tools & weaponsHomo erectus-Hand axes-Probably used fire-Spears-Clubs-Digging sticks-Language-Chimpanzees use > 20 sounds for specific meaning (“words”).-Trained to use American sign language & so the brain is adequate to handle simple speech. ***But….…their vocal apparatus seems to be inadequate**-Two major differences between human & chimp:-Shift in tongue position-Lengthening of Pharyngeal tract -Australopithicus -Like a chimpanzee-Neanderthals -Probably were able to speak.-Today (Homo Homo Sapiens)-10,000 Languages, One origin- FOXP2 located on chromosome 7 found mutated in family with language dysfunction. Called the “language gene.”-FOXP2 is present in vocal and non-vocal animals & its loss is associated with motor skills and coordination including those of the mouth and face. In humans, its loss by mutation causes disturbance in language comprehension, grammar and syntax-FOXP2 has rapidly evolved (2 amino acid substitutions since chimps.) ***Speculation that this difference is responsible for human speech. Neanderthals have the same FOXP2 gene structure as modern humans!***Four Interesting Problems1. How do the Neanderthals fit into the family tree?-Complete mitochondrial DNA analysis of a Neanderthal shows 206 nucleotide differences between H.neanderthalis and H. sapiens -Species split ~ 660,000 years ago-Neanderthals lived in Europe & Middle East 200,000-23,000 yrs. (Gibraltar the last stronghold) -Homo sapiens arrived in Europe ~40,000 yrs ago & lived together with Neanderthals-In 2007 a research team from the University of Leipzig announced they isolated a pigmentation gene (MC1R) suggesting that at least some Neanderthals had red hair, pale skin, and possibly freckles. -The gene is unlike the red-haired gene of modern humans—evolved independently.-Volcanic ash dated~40,000 years ago in the Caucasus region suggests that major climatic change.-The Neanderthals became extinct except for a few isolated populations inthe South of Europe.-Did humans and Neanderthals interbreed?-Yes. 1%--4% DNA of modern humans who live outside of Africa have Neanderthal DNA.2. What are the migration patterns of humans?-Mitochondrial “Eve”-DNA in mitochondria. Only mother gives mitochondria to young.-Tracing mitochondrial DNA shows Africans to be the oldest group of H. sapiens.-Origin of H. sapiens 200,000 years ago in Africa. A very small population gave rise to modern humans-Y Chromosome Data-All humans are descended from an African man who lived 59,000 yrs ago.-So, Eve lived more than 100,000 yrs before Adam!-They walked across a land bridge!3. Why are there different races?-3->35+ (Natural Selection – specialized for different environments)-skin color (variations in melanin pigment)-North- less sunlight—>less vitamin D->Less calcium->More rickets. (SLC24A5 causes pale skin)-To prevent rickets-> Lose pigment !-South- more sunlight->sunburn and hypervitamintosis D->Keep pigment4. When did we lose our body hair & develop clothing?-Through natural selection and sexual selection!In 2004, found in cave on island Flores ~18k y.agoHomo floresiensis (3 feet
View Full Document
Unlocking...