BIOL 1108 Edition 1nd Lecture 26 Outline of Last Lecture I Learning Objectives II In The News III Levels of Biodiversity IV Conservation at the Population Level V Conservation at the Landscape Level VI Human Impacts on the Earth Outline of Current Lecture I Questions about Human Evolution II Comparative anatomy of apes III Trees IV Human Genome V Evidence VI In The News Current Lecture I Questions about Human Evolution What do you believe is the primary reason why some people do not accept that human beings and the other great apes share a close common ancestor Who was the first person to suggest that humans and other great apes such as chimps orangutans and gorillas be grouped together o Carl Linnaeus These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II III The Swedish naturalist who explored much of the old and new world describing and naming the world s plants and animals In the 9th edition of Systema Naturae Linnaeus referred to humanity as Homo diurnis or man of the day Couldn t not make a biological dinstinction between the two based on the science available to him Linneaus broke the human races down into various subspecies European Asian African Native American o Charles Darwin Disproved that African were an intermediate forms between apes and humans Favored races successful varieties Racism has played a large role in the rejection of Darwin s ideas Descent of Man there was no justification for separating humans from the animals let alone separating one group of human beings from another Comparative anatomy of apes o Very few differences anatomically between humans and apes o All the great apes have nearly identical muscle groups and internal organs including an appendix o Discovered in 1974 Lucy is a very complete skeleton 40 o of an early hominid Age 3 2 million years An adult female of 25 years o Chimps are known to exhibit many behaviors that had previously been thought to be exclusively associated with humans Among these are jealousy kindness laughter mourning revenge and altruism o A comparison of Clint s genetic blueprint with that of the human genome shows that our closest living relatives share 96 of our DNA Using the same type of analysis it was shown that the number of genetic differences between humans and chimps is ten times smaller than that between mice and rats Based on genetic relatedness chimps and humans are almost 99 identical Trees Phylogenetic relationships closely related to gorillas and chimps Most likely common ancestor gave rise to chimps and humans Guinea pigs apes some fruit bats and humans lack the ability to endogensouly produce ascorbic acid vitamin C IV V o In humans and apes this is due to a defective gene trait that in other mammals codes for GULOP an essential enzyme in the vitamin C synthesis pathway o The non functional GULOP is found throughout the Haplorrhini suborder of primates and is shared genetic character that strongly suggests a common ancestor for the apes and humans o We don t pay the price because we compensate the lack of vitamin c in our diets Human Genome Humans have 46 chromosomes and all other great apes of 48 Human chromosome number 2 is very long Apes have two genes that contain the same information as just one of our genes o All of the genes found on human chromosome 2 can be found on one or the other matching chromosomes in the other great apes We might come from an ancestor that had 2 and then ours fused together o Telomeres are found at the ends of chromosomes and do not code for proteins and thus no extinction genes were lost during the gene fusion event Compare genes of parasites o The human body louse indeed evolved from the louse found in chimps but happened recently 42 000 72 000 years ago Humans must have been wearing clothes at least since this time o There are two subspecies 1 One that are adapted to living in hair hair lice 2 And another with larger hooks for clothes 3 A more recent study of pubic lice suggests that humans acquired our public lice through sexual contact with the ancestors of gorillas but that this occurred several million years after the hominid and gorilla branches of the tree had diverged How a Humans had sex with gorillas once Evidence 4 4 million years old Ardipithecus ramidus from Ethiopia o Had opposable thumbs and toes 1 For tree dwelling o Teeth show an intermediate form between humans and chimps o Hips are broad like humans for walking Simple tools for collecting termites or for crushing things o Not much different from modern ape tools The earliest Homo species homo habilis arose 1 9 mya o Tool users Homo erectus VI o Arose in Africa and migrated out of Africa 100 000 yrs ago o Because of the discovery of fire o Colonization was associated with a small effective population size which is still evident in low genetic variation within and among contemporary populations outside of Africa o Modern Homo sapiens overlapped with Neanderthals but abruptly replaced them did not interbreed Denisovans o Related to but separate from the Neanderthals o A group of humans in Melanesia contain certain variants of genes that are uniquely found in Denisovan DNA Denisovans interbred with modern humans Neanderthals o Inhabited Europe and parts of western Asia 230 000 to 29 000 years ago o Well developed family and clan structures o Gene sequences from modern humans and at least 5 individual Neanderthals confirms the idea that they were a separate species that diverged from our own about 500 000 years ago o Recent evidence suggests that non African Homo sapiens have received 1 4 of their genes from interbreeding with Neanderthals In The News Why is it that the people of Tibet are able to survive at very high altitudes The EPAS1 gene was more than twice as common among the Tibetans Upon further research she learned that this gene is involved in the response to hypoxia EPAS1 alters the distribution of oxygen through red blood cells but does not involve the production of extra red blood cells